Gord, I'm full of Bright Ideas Lately.
Henri Wilson
Have you ever sat and watched the surface of a calm pond of water.
Every so often, a line will dart across the surface as though an extremely fast
fish is swimming just underneath.
Of course that isn't the case.
The line is the point of intersection of two small waves on the surface, moving
in slightly different directions.... or at least that is my interpretation. It
could just as easily be related to air movement.
The same effect can be seen when the bow waves of two boats interfere.
I was wondering if there might be some kind of analogy with light here.
Photons are supposed to be dimensionles points.
So are these points of wave interference on the water surface.
They can also move at very high speeds.
I know this all sounds pretty stupid because there would have to be an
unthinkable amount of interfering wave activity out there to give rise to the
vast number of photons in the universe...but I though some people might be
amused by the concept.
HW.
www.users.bigpond.com/hewn/index.htm
Sometimes I feel like a complete failure.
The most useful thing I have ever done is prove Einstein wrong.
Sue...
Henri Wilson wrote:
> Here's a thought.
>
> Have you ever sat and watched the surface of a calm pond of water.
>
> Every so often, a line will dart across the surface as though an extremely fast
> fish is swimming just underneath.
>
> Of course that isn't the case.
>
> The line is the point of intersection of two small waves on the surface, moving
> in slightly different directions.... or at least that is my interpretation. It
> could just as easily be related to air movement.
>
> The same effect can be seen when the bow waves of two boats interfere.
>
> I was wondering if there might be some kind of analogy with light here.
> Photons are supposed to be dimensionles points.
Indeed there is. When light from two sources converges at
a charge, the charge responds to the vector sum of the two
voltages.
Sue...
Androcles
"Henri Wilson" <H@..> wrote in message
news:ga4nd11lqo2f5s3fu...@4ax.com...
| Here's a thought.
|
| Have you ever sat and watched the surface of a calm pond of water.
Yeah, I live to fish.
|
| Every so often, a line will dart across the surface as though an
extremely fast
| fish is swimming just underneath.
That's MY line, I'm casting.
|
| Of course that isn't the case.
|
| The line is the point of intersection of two small waves on the
surface, moving
| in slightly different directions.... or at least that is my
interpretation. It
| could just as easily be related to air movement.
Nah.... it's 6 lb test nylon with a hook, bait and a sinker attached
one end
and a rod and reel the other. :-)
|
| The same effect can be seen when the bow waves of two boats interfere.
|
| I was wondering if there might be some kind of analogy with light
here.
| Photons are supposed to be dimensionles points.
Really? My photons are not dimensionless, they are as wide as the
beam. Marconi's first photons were this big
http://news.bbc.co.uk/olmedia/1700000/images/_1701461_aerial_n_150_marconi.jpg
| So are these points of wave interference on the water surface.
| They can also move at very high speeds.
|
| I know this all sounds pretty stupid because there would have to be an
| unthinkable amount of interfering wave activity out there to give rise
to the
| vast number of photons in the universe...but I though some people
might be
| amused by the concept.
Not stupid... atoms let off some small photons at high frequencies and
short
wavelengths. The only stupid part is see is the claim that photons are
points.
Androcles.
Gregory L. Hansen
Henri Wilson <hw@..> wrote:
>Here's a thought.
>
>Have you ever sat and watched the surface of a calm pond of water.
>
>Every so often, a line will dart across the surface as though an extremely fast
>fish is swimming just underneath.
>
>Of course that isn't the case.
Ever sat and watched the surface of a calm pond of water, then threw your
hands up and saw a half dozen lines darting across the surface as though a
bunch of fish were startled and swam away?
--
"We don't grow up hearing stories around the camp fire anymore about
cultural figures. Instead we get them from books, TV or movies, so the
characters that today provide us a common language are corporate
creatures" -- Rebecca Tushnet
Ben Rudiak-Gould
> The line is the point of intersection of two small waves on the surface, moving
>
> I was wondering if there might be some kind of analogy with light here.
> Photons are supposed to be dimensionles points.
> So are these points of wave interference on the water surface.
> They can also move at very high speeds.
These points of intersection can move faster than c even in a relativistic
universe (the famous "superluminal scissors"), so I don't think they can be
used to explain light.
-- Ben
Henri Wilson
(Gregory L. Hansen) wrote:
>In article <ga4nd11lqo2f5s3fu...@4ax.com>,
>Henri Wilson <hw@..> wrote:
>>Here's a thought.
>>
>>Have you ever sat and watched the surface of a calm pond of water.
>>
>>Every so often, a line will dart across the surface as though an extremely fast
>>fish is swimming just underneath.
>>
>>Of course that isn't the case.
>
>Ever sat and watched the surface of a calm pond of water, then threw your
>hands up and saw a half dozen lines darting across the surface as though a
>bunch of fish were startled and swam away?
That happens too, Greg.
But I can assure you what I defined DOES really happen. My first reaction, too,
was that a fish caused the movement.... but the bloody thing would have crashed
at about 200kms/hr into the bank and killed itself.
Henri Wilson
>
>"Henri Wilson" <H@..> wrote in message
>news:ga4nd11lqo2f5s3fu...@4ax.com...
>| Here's a thought.
>|
>| Have you ever sat and watched the surface of a calm pond of water.
>
>Yeah, I live to fish.
>|
>| Every so often, a line will dart across the surface as though an
>extremely fast
>| fish is swimming just underneath.
>
>That's MY line, I'm casting.
>|
>| Of course that isn't the case.
>|
>| The line is the point of intersection of two small waves on the
>surface, moving
>| in slightly different directions.... or at least that is my
>interpretation. It
>| could just as easily be related to air movement.
>
>Nah.... it's 6 lb test nylon with a hook, bait and a sinker attached
>one end
>and a rod and reel the other. :-)
Try fishing in a still pond rather than a flowing river. You will see these
occasional darting 'waves' if you watch closely. Some are quite large.
You might catch a fatter fish, too.
>
>|
>| The same effect can be seen when the bow waves of two boats interfere.
>|
>| I was wondering if there might be some kind of analogy with light
>here.
>| Photons are supposed to be dimensionles points.
>
>Really? My photons are not dimensionless, they are as wide as the
>beam. Marconi's first photons were this big
>http://news.bbc.co.uk/olmedia/1700000/images/_1701461_aerial_n_150_marconi.jpg
>
>| So are these points of wave interference on the water surface.
>| They can also move at very high speeds.
>|
>| I know this all sounds pretty stupid because there would have to be an
>| unthinkable amount of interfering wave activity out there to give rise
>to the
>| vast number of photons in the universe...but I though some people
>might be
>| amused by the concept.
>
>
>Not stupid... atoms let off some small photons at high frequencies and
>short
>wavelengths. The only stupid part is see is the claim that photons are
>points.
I agree, I was only trying to force the SRians to reluctantly agree with
someting I said .
>
>Androcles.
Androcles
"Henri Wilson" <H@..> wrote in message
| On Mon, 18 Jul 2005 15:08:44 GMT, "Androcles" <Androcles@ MyPlace.org>
wrote:
|
| >
| >"Henri Wilson" <H@..> wrote in message
| >news:ga4nd11lqo2f5s3fu...@4ax.com...
| >| Here's a thought.
| >|
| >| Have you ever sat and watched the surface of a calm pond of water.
| >
| >Yeah, I live to fish.
| >|
| >| Every so often, a line will dart across the surface as though an
| >extremely fast
| >| fish is swimming just underneath.
| >
| >That's MY line, I'm casting.
| >|
| >| Of course that isn't the case.
| >|
| >| The line is the point of intersection of two small waves on the
| >surface, moving
| >| in slightly different directions.... or at least that is my
| >interpretation. It
| >| could just as easily be related to air movement.
| >
| >Nah.... it's 6 lb test nylon with a hook, bait and a sinker attached
| >one end
| >and a rod and reel the other. :-)
|
| Try fishing in a still pond rather than a flowing river. You will see
these
| occasional darting 'waves' if you watch closely. Some are quite large.
|
| You might catch a fatter fish, too.
The canals of Port Charlotte, Florida, above the dykes,
are shallow and weed-filled, with a barely noticable flow unless it has
rained.
There are two-foot long large mouthed bass in those still waters.
Below the dykes the canals are open to the Gulf of Mexico, and crab
are abundant (and delicious).
The waters of Lake Arthur, Pennsylvania, are calm and there is a speed
limit for boats to avoid large wakes. Small-mouthed bass and blue-gills
inhabit the lake.
The Ohio river, downstream from Pittsburgh, contains catfish,
pike, bass and carp.
Here the Medway estuary, 1/2 a mile away, is salt water and tidal.
Further upstream, beyond Allington lock, the water is calm and flowing.
Bream are to be found there.
I have also fished off the Florida coast, where dolphin race with the
yacht,
and Deep Creek, Maryland, where I caught a fish I could not identify.
All this I know from personal experience, either from having caught fish
there, seeing fish there, or seeing others catch fish there.
Usually when fishing I ponder the Nature around me, the ripples on
the water, the dragonflies darting and hovering, I enjoy the serenity
of it all.
Relativists are hypocrites. I've told bz that faith cannot be overcome
by logic, he denies that.
bz wrote:
> I prayed to St. Wm of Ockham and asked which I should believe in.
> [quote]
> Believe in neither.
> Collect the data.
> Verify the data.
> Have others verify the data.
> Test your theories each day against new data as it comes in.
> Test the simplest theories first.
> Until falsified, let the theory 'stand' but test it every day.
> Leave the testing of equivalent but more complex theories for when
> they are needed to explain new data.
>
> Put your faith in no one who claims to know the truth,
> for all who claim to KNOW are false gurus.
>
> Put your FAITH in no theory,
> for no theory will stand forever.
> All theories will eventually be superceeded, even this one.
>
> [unquote]
Then he wrote:
I believe that 0.99938 [c] is close enough...
Bz has also written (as part of his "derivation")
quote
| Suppose a particle has the velocity of c in S.
| In system S' it must also have the same velocity because the two
| coordinate systems were assumed to be inertial wrt each other (no
| acceleration, constant velocity).
unquote.
which is illogical claptrap that is unsupported by anything except his
faith,
faith being what he believes.
Even Einstein, his tin god, said "But the ray moves relatively to the
initial point of k,
when measured in the stationary system, with the velocity c-v..."
As you can see, he's resorted to hypocrisy.
You will not overcome faith with logic, not for a Jehovah's Witness nor
a
Relativist.
Androcles.
Tim Golden
Henri Wilson wrote:
> Have you ever sat and watched the surface of a calm pond of water.
> Every so often, a line will dart across the surface as though an extremely fast
Yes. I have seen this too. It is fascinating.
It appears as a discrfete rather than continuous phenomena.
I am wondering if this is to do with a critical angle in the system.
So that the actual process is continuous but the observed effect is
discrete.
Let's not forget that the wind causing this effect is the result of a
vertical flow. That vertical flow has a maxima and there is a
translational horizontal component. It makes me think of a toy that I
recently was introduced to. Its a diaphragm hooked to a bungy cord in a
tube. You pull the thing back and it throws a highly directed flow of
air as far as thirty feet. Strong enough to knock over a beer can at
ten feet. I think that might be the actual effect going on on the calm
water, just naturally composed.
-Tim
Autymn D. C.
Henri Wilson
>
>"Henri Wilson" <H@..> wrote in message
>news:m5fod15riocvisg05...@4ax.com...
>| On Mon, 18 Jul 2005 15:08:44 GMT, "Androcles" <Androcles@ MyPlace.org>
>wrote:
>|
>| Try fishing in a still pond rather than a flowing river. You will see
I used to fish a great deal. Gave it up about ten years ago when I realised
fish don't particularly like being dragged out of the water with a bloody big
hook stuck in their palates.
Still I guess they don't like being bitten in half or swallowed whole by bigger
fish either.
The only things I fish out of creeks now are golf balls.
As the pope said, give me a child before the age of five and I will have him
for life.
Bz must have read about Einstein when he was a 4yo.
Henri Wilson
>
>
>Henri Wilson wrote:
>> Have you ever sat and watched the surface of a calm pond of water.
>> Every so often, a line will dart across the surface as though an extremely fast
>Yes. I have seen this too. It is fascinating.
>It appears as a discrfete rather than continuous phenomena.
>I am wondering if this is to do with a critical angle in the system.
>So that the actual process is continuous but the observed effect is
>discrete.
I thought it must involve two low amplitude waves that have reflected off
opposite banks of the pond. If they meet slightly off parallel, their junctions
would move much faster than the waves themselves.
It IS like the point where a pair of scissor blades meet....as someone pointed
out.
>Let's not forget that the wind causing this effect is the result of a
>vertical flow. That vertical flow has a maxima and there is a
>translational horizontal component. It makes me think of a toy that I
>recently was introduced to. Its a diaphragm hooked to a bungy cord in a
>tube. You pull the thing back and it throws a highly directed flow of
>air as far as thirty feet. Strong enough to knock over a beer can at
>ten feet. I think that might be the actual effect going on on the calm
>water, just naturally composed.
Interesting.
One would think that turbulence would disperse the air very quickly.
I think that there might be a critical condition involved here.
>-Tim
Androcles
"Henri Wilson" <H@..> wrote in message
Man is an omnivore. I eat what I kill, I eat what I pay others to kill
for me.
I don't approve of fox hunting unless the huntsmen eat the fox.
Back to photons.
Light is a wave, ripples on water are waves.
So what's the difference between ripples on water and a beam of light?
Answer : Shape.
The bow wave of a boat moving faster than the speed of waves on water
has a different (straight line) shape to circular ripples. It is still a
wave.
Imagine a SINGLE crest expanding outwards in a circle.
All the energy eventually reaches the shore, everywhere.
Imagine the same crest originating at the focus of a parabolic wall.
It is reflected to a straight line. That's a photon. All the energy
arrives
at one place on the shore.
Well ok, I've oversimplified, but I'm trying to resolve wave/particle
duality.
Androcles.
Eric Gisse
Henri Wilson wrote:
> Here's a thought.
>
> Have you ever sat and watched the surface of a calm pond of water.
>
> Every so often, a line will dart across the surface as though an extremely fast
> fish is swimming just underneath.
>
> Of course that isn't the case.
>
> The line is the point of intersection of two small waves on the surface, moving
> in slightly different directions.... or at least that is my interpretation. It
> could just as easily be related to air movement.
>
> The same effect can be seen when the bow waves of two boats interfere.
>
> I was wondering if there might be some kind of analogy with light here.
> Photons are supposed to be dimensionles points.
> So are these points of wave interference on the water surface.
> They can also move at very high speeds.
Congratulations, you have achieved 19th century understanding of light.
You are only a century and change behind modern understanding. Quite an
improvement I think. It is that much less reinventing of the wheel you
have to do before you come to accept what we have known since before
you were born.
>
> I know this all sounds pretty stupid because there would have to be an
> unthinkable amount of interfering wave activity out there to give rise to the
> vast number of photons in the universe...but I though some people might be
> amused by the concept.
Yes, it is clearly wave interference that is causing the sun to emit so
many photons.
Now advance your knowledge 60 years to reach the mid twentith century
when people started to realise that nuclear reactions emit photons.
Along the way you will also pick up quantum mechanics and the line of
thought that inspired it.
With God willing, you will stop being such a moron.
Henri Wilson
I now buy all mine from a local fisherman who sells it fresh and cheap from the
back of his truck.
>I don't approve of fox hunting unless the huntsmen eat the fox.
Raw?
It's a hard one.
I think there is an entirely different explanation for light....neither wave
NOR particle.
Henri Wilson
geese, do you really think you achieved anything useful by compiling this crap?
Androcles
"Henri Wilson" <H@..> wrote in message
They can please themselves, just don't kill for sport unless you eat it.
What is it, then?
Eric Gisse
Henri Wilson wrote:
[snip]
>
> geese, do you really think you achieved anything useful by compiling this crap?
Yea. I raised the entropy of the solar system just a little.
Increasing entropy is my minimum standard for accomplishment.
sal
Here is some food for thought:
Go to the mirror.
Open your mouth.
Look inside, see your teeth. Really look at them.
Look at a photograph of a raccoon's teeth (or look at an actual 'coon, or
its skull, if you have one handy).
See the canines, see those impressive points.
A raccoon is an omnivore. It eats plants and it eats meat, and it has
teeth to let it do both (_without_ cooking the stuff or cutting it up
with a Swiss army knife first, of course).
Look at a chimpanzee's teeth.
A chimp is an omnivore, too. Some canines! Pretty impressive, huh? Not
much like yours, I warrant.
Look at a cow's teeth. Where are the canines? Oops, there aren't any --
bunch of molars, but nothing for tearing meat. Kind of like human teeth,
wouldn't you say? Bigger, of course, but the same general idea.
Look how a cow's jaw moves: up and down _and_ side to side. Look how,
say, a dog's jaw moves: just up and down. Now look how your jaw moves: up
and down _and_ side to side.
If man is supposed to be an omnivore then man has a very weird set of
teeth for the job.
"Beefeaters" -- pfui. Figure out how to make your own vitamin C, figure
out how to handle a diet sky-high in saturated fat without wrecking your
health (dogs can do both, you know). Then you can call yourself a
"beefeater". Otherwise you'd be better off sticking to beans, berries,
and leaves.
> I eat what I kill,
Me too, usually. Man those leaves scream when I put 'em in the steamer...
By the way, what do you do if your house has mice? When you take them
out of the traps, do you ... oh, that's right, you've got a cat, I guess
you farm that one out, eh?
Well, you're a fisherman, you must have encountered mosquitoes from time
to time. Do you swat them? What do you do with them afterwards? If
you eat what you kill, does that mean ... eccch...
> I eat what I pay others to kill for me.
I prefer to buy my greens while they're still alive.
But when I had an exterminator in to get rid of the termites, I confess I
just left the bodies lying there afterwards. Couldn't stomach the idea of
eating them.
> I don't
> approve of fox hunting unless the huntsmen eat the fox.
Agreed!
A couple paragraphs back, Henri Wilson said:
>| I used to fish a great deal. Gave it up about ten years ago when I
>| realised fish don't particularly like being dragged out of the water
>| with a bloody big hook stuck in their palates.
>| Still I guess they don't like being bitten in half or swallowed whole
>| by bigger fish either.
>| The only things I fish out of creeks now are golf balls.
Yeah, I can go along with that. I gave up fishing about 30 years ago.
> | >| I agree, I was only trying to force the SRians to reluctantly agree
> | >| with someting I said .
Hey, I just did. Does that count?
--
Nospam becomes physicsinsights to fix the email
Androcles
"sal" <pragm...@nospam.org> wrote in message
news:pan.2005.07.22....@nospam.org...
Tell it to the whale. They are carnivores without shark teeth.
Krill eaters -- pfui.
"Godfrey thinks it was a baleen whale, meaning it would gulp water and
then force it out across hairy plates in its mouth, trapping food. He's
unsure if it was an ancestor of modern baleen whales, like the humpback
or part of an extinct line of whales."
http://www.rednova.com/news/display/?id=40338
|
| > I eat what I kill,
|
| Me too, usually. Man those leaves scream when I put 'em in the
steamer...
Scream like lobster?
| By the way, what do you do if your house has mice? When you take them
| out of the traps, do you ... oh, that's right, you've got a cat, I
guess
| you farm that one out, eh?
He usually brings them to me as an offering of peace and friendship.
They come from outside, though, no self-respecting mouse would want
to live in my hovel.
A previous cat that once owned me gave me the back end of a squirrel
and a complete chipmunk.
He preferred to release birds in the house, either for me to catch or to
demonstrate his prowess at catching them, I'm not sure which.
He knocked over ornaments, though, so I was not all that impressed.
I told him I thought that was cheating, I didn't knock over ornaments.
He didn't seem to care. I carefully explained that when a horse and
rider
partake in show jumping, a respectable sport, there is a 4 fault penalty
for knocking a bar off a gate, and fox-hunting wasn't a respectable
sport.
To no avail, alas.
He looked at me as if I didn't realize birds were not foxes, I wasn't a
horse
and the objective was to catch the bird without harming it, then release
it
and capture it again. His rules, his sport. You just can't talk to some
cats.
You can't talk to relativists, either. They don't know what the rules
are
and play their own game.
| Well, you're a fisherman, you must have encountered mosquitoes from
time
| to time. Do you swat them?
Nah.. I gave up swatting skeeters in India, they had me outnumbered.
Same in Florida, where they are called "can't-see-'ums".
Keep your eyes on the gators and you won't see em, either.
What do you do with them afterwards? If
| you eat what you kill, does that mean ... eccch...
Like I said, I don't swat 'em.
I swat relativists, that doesn't kill 'em though.
Ya gotta tear their heads off to do that.
"Hagrid had Norbert packed and ready in a large crate.
'He's got lots o' rats an' some brandy fer the journey',
said Hagrid in a muffled voice. 'An' I packed his teddy
bear in case he gets lonely'.
From inside the crate came ripping noises that sounded
to Harry as though teddy was having his head torn off."
J.K. Rowling, "Harry Potter and the Philosopher's Stone."
|
| > I eat what I pay others to kill for me.
|
| I prefer to buy my greens while they're still alive.
Really? So you get them from the farm where you collect them
from the plant after paying for them?
I have some potatoes in the kitchen that are sprouting roots,
but they aren't green. I'm gonna kill 'em for dinner before they
shrivel.
|
| But when I had an exterminator in to get rid of the termites, I
confess I
| just left the bodies lying there afterwards. Couldn't stomach the
idea of
| eating them.
Ugh... I'd have swept them up, but I've never had an exterminator in so
I don't have your experience. I killed some fleas once, I'll confess
I didn't eat them. I figure they belonged to the cat and not mine to
steal.
He brought them in, after all, and not as a peace offering. I turned
down
his mouse, too. When he decided he preferred a can of "Felix" to mouse
steaks, I flushed it to prevent the attraction of flies. Fly chops are a
devil to
cook, I don't have small enough onions to go with them.
|
| > I don't
| > approve of fox hunting unless the huntsmen eat the fox.
|
| Agreed!
|
|
| A couple paragraphs back, Henri Wilson said:
|
| >| I used to fish a great deal. Gave it up about ten years ago when I
| >| realised fish don't particularly like being dragged out of the
water
| >| with a bloody big hook stuck in their palates.
| >| Still I guess they don't like being bitten in half or swallowed
whole
| >| by bigger fish either.
| >| The only things I fish out of creeks now are golf balls.
|
| Yeah, I can go along with that. I gave up fishing about 30 years ago.
So you don't eat fish, or you buy fish?
How about eggs, those are animal protein?
Ever killed an egg and eaten it? I do, often.
See, fishing for food has a random element to it. Sometimes you catch
a fish that is either too small and won't fill your belly and you have
to catch
another, or one that is too large and that's wasteful. I don't kill
those, I throw
them back alive. I can't claim to have ever caught a fish so large I
couldn't eat
it, though. You can't tell what you've got until after you've caught it.
It is a moral dilemma, I agree. I'm sure Henri is right, they don't like
bloody big hooks stuck in their palates, but I gotta eat. So I
compromise
and throw the little ones back after surgery to remove the hook and
euthanize the ones I intend to munch on. If you can't kill it yourself,
don't eat it, and if you don't intend to eat it, don't kill it, I say.
|
|
| > | >| I agree, I was only trying to force the SRians to reluctantly
agree
| > | >| with someting I said .
|
| Hey, I just did. Does that count?
Dunno, only Henri should answer that.
Let's see if you agree with me, or can give a reason why not.
If we wish to describe the motion of a material point, we give the
values of its co-ordinates as functions of the time. Now we must bear
carefully in mind that a mathematical description of this kind has no
physical meaning unless we are quite clear as to what we understand by
``time.'' We have to take into account that all our SUBJECTIVE
judgments in which time plays a part are always judgments of
simultaneous events. If, for instance, I say, ``That train arrives here
at 7 o'clock,'' I mean something like this: ``The pointing of the small
hand of my watch to 7 and the arrival of the train are simultaneous
events.''3
It might appear possible to overcome all the difficulties attending the
definition of ``time'' by substituting ``the position of the small hand
of my watch'' for ``time.'' And in fact such a definition is
satisfactory when we are concerned with defining a time exclusively for
the place where the watch is located; but it is no longer satisfactory
when we have to connect in time series of events occurring at different
places, or--what comes to the same thing--to evaluate the times of
events occurring at places remote from the watch.
We might, of course, content ourselves with time values determined by an
observer stationed together with the watch at the origin of the
co-ordinates, and co-ordinating the corresponding positions of the hands
with light signals, given out by every event to be timed, and reaching
him through air. But this co-ordination has the disadvantage that it is
not independent of the standpoint of the observer with the watch or
clock, as we know from experience. We arrive at a much more practical
determination along the following line of thought.
If at the point A of space there is a clock, an observer at A can
determine the time values of events in the immediate proximity of A by
finding the positions of the hands which are simultaneous with these
events. If there is at the point B of space another clock in all
respects resembling the one at A, it is possible for an observer at B to
determine the time values of events in the immediate neighbourhood of B.
But it is not possible without further assumption to compare, in respect
of time, an event at A with an event at B. We have so far defined only
an ``A time'' and a ``B time.'' We have not defined a common ``time''
for A and B, for the latter cannot be defined at all unless we establish
by definition that the ``time'' required by sound to travel from A to B
equals the ``time'' it requires to travel from B to A.
Conclusion (after a long drawn out argument you can read for yourself,
just substitute "light" for "sound") :
gamma = 1/sqrt(1 -v^2/Mach1^2)
"Now we must bear carefully in mind that a mathematical description of
this kind has no physical meaning unless we are quite clear as to what
we understand by 'time'. " -- Albert Einstein.
"we establish by definition that the ``time'' required by SOUND to
travel from A to B equals the ``time'' it requires to travel from B to
A. -- Androcles (with tongue in cheek)
sue jahn
"Androcles" <Androcles@ MyPlace.org> wrote in message news:rrbEe.23608$yP3....@fe1.news.blueyonder.co.uk...
>
snip
IMHO it is much easier than that.
If Annie Oakley and Buffalo Bill have identical watches,
They should be able to use the watches to predict how
much fuel they burn in a drag race. They should be able to
use the watches to cause the midpoint collision of bullets.
If the pair of watches does those two things regardless of
their location, then it is a good bet the watches are
reasonable simulations of the passage of time.
No reason to overturn our notion of time just because
neither Einsten nor Heviside saw fit to teach Maxwell
about reactance in the near field.
Sue...
Fourspace is where Maxwell radiates.
Euclidian space is where Coulomb radiates.
http://www.iop.org/EJ/abstract/0305-4470/30/10/036
>
>
>
>
>
sal
rather long.
On Fri, 22 Jul 2005 19:04:55 +0000, Androcles wrote:
>
> "sal" <pragm...@nospam.org> wrote in message
> news:pan.2005.07.22....@nospam.org...
> | On Wed, 20 Jul 2005 03:59:36 +0000, Androcles wrote:
> |
> |
> | > "Henri Wilson" <H@..> wrote in message
> | > news:1gard1ps9h0ee9ic3...@4ax.com...
> | > | On Tue, 19 Jul 2005 12:38:44 GMT, "Androcles" <Andr...@MyPlace.org>
> | > wrote:
> | >
> | > Man is an omnivore.
> |
> | Here is some food for thought:
> |
> | Go to the mirror.
> |
> | Open your mouth.
> |
> | Look inside, see your teeth. Really look at them.
[ snip ]
> | If man is supposed to be an omnivore then man has a very weird set of
> | teeth for the job.
> |
> | "Beefeaters" -- pfui. Figure out how to make your own vitamin C, figure
> | out how to handle a diet sky-high in saturated fat without
> | wrecking your
> | health (dogs can do both, you know). Then you can call yourself a
> | "beefeater". Otherwise you'd be better off sticking to beans, berries,
> | and leaves.
>
>
> Tell it to the whale. They are carnivores without shark teeth. Krill
> eaters -- pfui.
You mean baleen whales, of course. They're specialized carnivores who
have teeth specialized to their diets, as do most animals, and in
fact their diets consist of small stuff -- far smaller than the fish,
birds, and mammals that most humans today eat. Toothed whales, OTOH,
have much more formidable teeth that are better adapted to their roles
as carnivores preying on relatively large animals (large relative to krill,
anyway). But no whales have diets remotely resembling the all-beef
all-the-time diet of many Americans, for example.
> | > I eat what I kill,
> |
> | Me too, usually. Man those leaves scream when I put 'em in the
> | steamer...
>
> Scream like lobster?
Only if you don't shoot the lobster first.
I've steamed crabs before, but never a lobster. Pretty gruesome,
really, if you think about it too much. Boiling is quicker but they
do put up a fuss when you drop them into the pot.
> | By the way, what do you do if your house has mice? When you take them
> | out of the traps, do you ... oh, that's right, you've got a cat, I
> | guess
> | you farm that one out, eh?
>
> He usually brings them to me as an offering of peace and friendship. They
> come from outside, though, no self-respecting mouse would want to live in
> my hovel.
>
> A previous cat that once owned me gave me the back end of a squirrel and a
> complete chipmunk.
>
> He preferred to release birds in the house, either for me to catch or to
> demonstrate his prowess at catching them, I'm not sure which. He knocked
> over ornaments, though, so I was not all that impressed. I told him I
> thought that was cheating, I didn't knock over ornaments. He didn't seem
> to care. I carefully explained that when a horse and rider
> partake in show jumping, a respectable sport, there is a 4 fault penalty
> for knocking a bar off a gate, and fox-hunting wasn't a respectable sport.
> To no avail, alas.
> He looked at me as if I didn't realize birds were not foxes, I wasn't a
> horse
> and the objective was to catch the bird without harming it, then release
> it
> and capture it again. His rules, his sport. You just can't talk to some
> cats.
:-) Indeed. Any cat, actually.
> You can't talk to relativists, either. They don't know what the rules are
> and play their own game.
>
[ ... ]
> |
> | > I eat what I pay others to kill for me.
> |
> | I prefer to buy my greens while they're still alive.
>
> Really? So you get them from the farm where you collect them from the
> plant after paying for them?
Green leafy vegetables generally stay alive until they wilt (or
they're cooked, which of course wilts them, too). The ones in the
store in the produce department are mostly still alive (save for the
rotten ones on the back of the bottom shelf).
> | Yeah, I can go along with that. I gave up fishing about 30 years ago.
>
> So you don't eat fish, or you buy fish?
I don't eat fish anymore. The stuff used to be health food, back some
time in the previous century. That was before the level of mercury, PCBs,
and other junk got so high in the waterways that the fish turned toxic.
But don't let me discourage you from eating them! After all, you only
live once, and you won't shorten your life (much) by eating modern
wild-caught fish.
> How about eggs, those are animal
> protein? Ever killed an egg and eaten it? I do, often.
Oh, you buy fertile eggs? AFAIK the infertile ones aren't alive but
then I've never put one under a microscope to check it out.
In any case I don't eat the things. Aside from the salmonella (which
didn't used to be there) and other nameless diseases spread as a
result of the atrocious conditions the chickens are kept in, there's
the issue of how they make eggs:
Hens are valuable. Roosters are not ('cause they don't lay eggs).
So, to supply the egg farmers, the breeders produce hens but no
roosters.
But you can't tell 'til they hatch what they are. So they let the
eggs hatch, and then a professional chick sexer examines them and
divides them into baby hens and baby roosters.
The hens go to the chicken coop. The baby roosters are disposed of.
Typical methods of disposal are crushing them, or just dumping them in
trashcans, alive, where they eventually starve, smother, or die of
heat exhaustion. To keep profits up the disposal must be _cheap_, of
course, which is why dumping live chicks into trash cans is a favored
approach. Crushing, on the other hand, saves space in the dumpster,
which makes it another favored approach.
So, each time you buy an egg, you're not destroying a potential chick
(it's not fertile). But you _are_ taking part in crushing to death
all those baby rooster chicks who had to be disposed of in order to
keep the henhouses stocked without leaving us hip-deep in commercially
useless birds.
Again, I no longer eat eggs (save by mistake when I order something in a
restaurant that contains eggs -- I'm not religious about it, after all.)
But don't let me discourage you from enjoying your next omelet! And
certainly don't do anything gross, like imagining the blood of the
crushed roosters poured over your plate! That might really interfere
with the pleasure of breakfast.
> See, fishing for food has a random element to it. Sometimes you catch a
> fish that is either too small and won't fill your belly and you have to
> catch
> another, or one that is too large and that's wasteful. I don't kill those,
> I throw
> them back alive. I can't claim to have ever caught a fish so large I
> couldn't eat
> it, though. You can't tell what you've got until after you've caught it.
> It is a moral dilemma, I agree. I'm sure Henri is right, they don't like
> bloody big hooks stuck in their palates, but I gotta eat. So I compromise
> and throw the little ones back after surgery to remove the hook and
> euthanize the ones I intend to munch on. If you can't kill it yourself,
> don't eat it, and if you don't intend to eat it, don't kill it, I say.
Yeah, that makes sense.
Except for those rooster chicks, of course, whose deaths are financed
by egg sales. When you buy eggs, you're paying somebody to kill the
unwanted chicks, but you're not eating those chicks. Hmmm.
> |
> | > | >| I agree, I was only trying to force the SRians to reluctantly
> | > | >| agree with someting I said .
> |
> | Hey, I just did. Does that count?
>
> Dunno, only Henri should answer that. Let's see if you agree with me, or
> can give a reason why not.
>
> If we wish to describe the motion of a material point, we give the
> values of its co-ordinates as functions of the time. Now we must bear
> carefully in mind that a mathematical description of this kind has no
> physical meaning unless we are quite clear as to what we understand by
> ``time.'' We have to take into account that all our SUBJECTIVE judgments
> in which time plays a part are always judgments of simultaneous events.
> If, for instance, I say, ``That train arrives here at 7 o'clock,'' I
> mean something like this: ``The pointing of the small hand of my watch
> to 7 and the arrival of the train are simultaneous events.''3
Clear. But what's that "3", anyway -- a footnote?
'Course you need to be standing on the platform when the train arrives
for the two events to be unambiguously "simultaneous", and in that
case they'd actually be considered to be a single event.
Right -- you've got the rules of inference but until you add a
postulate you haven't got much in the way of conclusions
> Conclusion (after a long drawn out argument you can read for
> yourself, just substitute "light" for "sound") :
>
> gamma = 1/sqrt(1 -v^2/Mach1^2)
Sure thing ... as long as you include that assumption that the speed
of sound wave is isotropic as measured by all inertial observers. And
that, of course, is equivalent to this assumption:
The speed of an object (or wave) traveling at Mach1 is measured as
being identical by all inertial observers
If you don't include that assumption, or one equivalent to it, then
you can't get to that conclusion.
> "Now we must bear carefully in mind that a mathematical description of
> this kind has no physical meaning unless we are quite clear as to what we
> understand by 'time'. " -- Albert Einstein.
Obviously.
> "we establish by definition that the ``time'' required by SOUND to travel
> from A to B equals the ``time'' it requires to travel from B to A. --
> Androcles (with tongue in cheek)
Sure. But now, with this general statement, you've forced mach1 to be
the "universal speed limit" instead of C (or rather you've used the C
for sound waves instead of light waves, since traditionally C was any
wave velocity). The resulting model will not match our universe in
numerous ways, starting with the fact that in your "mach 1" universe,
it would take infinite energy to accelerate an airplane to mach 1.
That's patently not true here, else the Concord could not have
performed as it did.
Androcles
"sue jahn" <susyse...@yahoo.com.au> wrote in message
news:42e16422$0$18647$1472...@news.sunsite.dk...
Use rocket powered dragsters. I've always advocated candles
as time measuring devices, and you can get a pretty big flame
from a Saturn V candle with a Discovery fuel tank. Just be careful
which end you light, don't burn the candle at both ends or in the
middle. Annie Oakley can fire when Bill's fuel gauge reads 1/2.
Androcles.
Androcles
I didn't claim to be a carnivore.
|
| > | > I eat what I kill,
| > |
| > | Me too, usually. Man those leaves scream when I put 'em in the
| > | steamer...
| >
| > Scream like lobster?
|
| Only if you don't shoot the lobster first.
Even if you do, they scream.
The noise is escaping heated gas coming through crevasses in the shell.
I didn't know green leaves could scream, though.
I learn something new every day.
Are you sure it wasn't the snails on the underside of the cabbage?
Ever tried steaming lettuce as an experiment?
| I've steamed crabs before, but never a lobster. Pretty gruesome,
| really, if you think about it too much. Boiling is quicker but they
| do put up a fuss when you drop them into the pot.
Even blue crabs turn lobster pink.
The one that presently owns me makes his wishes known, I have say
"back" quite sternly when loading his food dish. He's catching on,
though.
He likes to have a good look inside the refrigerator for the opened can,
too.
"Back", I say, to close the fridge door, and he steps back, as soon as
he sees
I've got the can.
|
| > You can't talk to relativists, either. They don't know what the
rules are
| > and play their own game.
| >
| [ ... ]
| > |
| > | > I eat what I pay others to kill for me.
| > |
| > | I prefer to buy my greens while they're still alive.
| >
| > Really? So you get them from the farm where you collect them from
the
| > plant after paying for them?
|
| Green leafy vegetables generally stay alive until they wilt (or
| they're cooked, which of course wilts them, too). The ones in the
| store in the produce department are mostly still alive (save for the
| rotten ones on the back of the bottom shelf).
Hmm.... I've never seen a sign of life in a detached leaf.
|
|
| > | Yeah, I can go along with that. I gave up fishing about 30 years
ago.
| >
| > So you don't eat fish, or you buy fish?
|
| I don't eat fish anymore. The stuff used to be health food, back some
| time in the previous century. That was before the level of mercury,
PCBs,
| and other junk got so high in the waterways that the fish turned
toxic.
|
| But don't let me discourage you from eating them! After all, you only
| live once, and you won't shorten your life (much) by eating modern
| wild-caught fish.
Well.... see, I don't much care for insecticide sprayed green leaves
myself. I'd rather eat peeled potatoes. After all, I am British and the
great delicacy of British cuisine is still the good ol' fish'n'chips
that I grew
up with, never has been peanut butter and jelly. But don't let me put
you off either. Enjoy your crop dusters.
|
|
| > How about eggs, those are animal
| > protein? Ever killed an egg and eaten it? I do, often.
|
| Oh, you buy fertile eggs? AFAIK the infertile ones aren't alive but
| then I've never put one under a microscope to check it out.
They are every bit as fertile as green leaves, and just as alive.
And they go well with bacon... Cabbage and bacon for breakfast?
Not for me. I don't think even Denny's has it on the menu.
Wouldn't bother me. Ever had black pudding? It's made from pig's blood.
Life is a compromise. What is life anyway? What's wrong with raising
roosters for food? Kentucky Fried Rooster sounds ok to me.
When I was seven years old I was at grandma's house for xmas dinner.
Her sister had given her a cock for xmas (her sister raised fertile
eggs)
so we thanked some "Lord" or other for the "bounty" and tucked into
cock. It tasted like chicken to me, and I said so. It was years later
that
I found out what a "bounty" was. Turns out it was a ship that the crew
mutiny'd on. I still don't know what that had to do with dinner,
though.
Roosters roost, don't they?
Roost: a support on which birds rest
a place where winged animals and especially birds customarily
roost
(that sounds batty)
a group of birds (as fowl) roosting together
What does sex have to do with resting?
You Americans are so mixed up with your word usage, it's little
wonder you think a dog goes to the bathroom in the street and the poor
bloody Englishman thinks you're crackers.
| |
| > | > | >| I agree, I was only trying to force the SRians to
reluctantly
| > | > | >| agree with someting I said .
| > |
| > | Hey, I just did. Does that count?
| >
| > Dunno, only Henri should answer that. Let's see if you agree with
me, or
| > can give a reason why not.
| >
| > If we wish to describe the motion of a material point, we give the
| > values of its co-ordinates as functions of the time. Now we must
bear
| > carefully in mind that a mathematical description of this kind has
no
| > physical meaning unless we are quite clear as to what we understand
by
| > ``time.'' We have to take into account that all our SUBJECTIVE
judgments
| > in which time plays a part are always judgments of simultaneous
events.
| > If, for instance, I say, ``That train arrives here at 7 o'clock,'' I
| > mean something like this: ``The pointing of the small hand of my
watch
| > to 7 and the arrival of the train are simultaneous events.''3
|
| Clear. But what's that "3", anyway -- a footnote?
yeah...
3.
We shall not here discuss the inexactitude which lurks in the concept of
simultaneity of two events at approximately the same place, which can
only be removed by an abstraction.
|
| 'Course you need to be standing on the platform when the train arrives
| for the two events to be unambiguously "simultaneous", and in that
| case they'd actually be considered to be a single event.
Aww... you discussed it already.
| postulate you haven't got much in the way of conclusions.
Ah, yes... You are right.
The same laws of audiodacity and acoustics will be valid for all frames
of reference for which the equations of optics hold good. We will raise
this conjecture (the purport of which will hereafter be called the
``Principle of Relativity'') to the status of a postulate, and also
introduce another postulate, which is only apparently irreconcilable
with the former, namely, that sound is always propagated in empty air
with a definite velocity Mach1 which is independent of the state of
motion of the emitting noisemaker.
|
| > Conclusion (after a long drawn out argument you can read for
| > yourself, just substitute "light" for "sound") :
| >
| > gamma = 1/sqrt(1 -v^2/Mach1^2)
|
| Sure thing ... as long as you include that assumption that the speed
| of sound wave is isotropic as measured by all inertial observers.
Huh? Look mate, I've already written the paper without use of the word
"isotropic"
or the word "inertial".
Mirriam Webster says:
"exhibiting properties with the same values when measured along axes in
all directions"
so I guess it's ok.
And
| that, of course, is equivalent to this assumption:
|
| The speed of an object (or wave) traveling at Mach1 is measured as
| being identical by all inertial observers
|
| If you don't include that assumption, or one equivalent to it, then
| you can't get to that conclusion.
Well, that wouldn't hold, of course. Inertial observers can still detect
doppler shift from the source and know they are moving through air,
but I have a newer version of Doppler coming right up to make it right.
1-cos(phi).v/Mach1
nu' = nu ----------------------
sqrt(1-v^2/Mach1^2)
AND I've got
Mach1 = (Mach1 +v)/(1 + v/Mach1).
Now they know that the speed of sound is measured to be Mach1 in all
frames
of reference. I said so.
| > "Now we must bear carefully in mind that a mathematical description
of
| > this kind has no physical meaning unless we are quite clear as to
what we
| > understand by 'time'. " -- Albert Einstein.
|
| Obviously.
Well then, I defined time, didn't I? You did understand it, I trust?
|
|
| > "we establish by definition that the ``time'' required by SOUND to
travel
| > from A to B equals the ``time'' it requires to travel from B to
A. --
| > Androcles (with tongue in cheek)
|
| Sure. But now, with this general statement, you've forced mach1 to be
| the "universal speed limit" instead of C
Yeah, sure.
But remember, it is NOT POSSIBLE without further assumption to compare,
in respect of time, an event at A with an event at B, unless I define
time the
way I want to and you agree with me.
(or rather you've used the C
| for sound waves instead of light waves, since traditionally C was any
| wave velocity).
Well, ok. But since 'C' was usurped by some other bloke to name a
programming language, I thought I'd specify Mach1.
| The resulting model will not match our universe in
| numerous ways, starting with the fact that in your "mach 1" universe,
| it would take infinite energy to accelerate an airplane to mach 1.
| That's patently not true here, else the Concord could not have
| performed as it did.
Concorde never once exceeded Mach1, ask the passengers
if they could talk to the flight attendants without sounding like they
had
breathed a lungful of helium. The speed of sound inside Concorde was
Mach1
and it performed perfectly well. Air inside, air outside. Want to
perform
MMX on the plane as well? Aether inside, aether outside, and I'm not
even an
aetherialist.
So what is it that is patently not true?
It took an enormous amount of energy to fly Concorde, which is
the main reason it was scrapped.
"Now we must bear carefully in mind that a mathematical description of
this kind has no physical meaning unless we are quite clear as to what
we
understand by 'time'. " -- Albert Einstein.
I'm not claiming my mathematical description has physical meaning,
I'm not THAT stupid. I have a different definition of time, but I'm
saving that
for Newton. Oops... he may have already undsetood it/
Any more objections for me to overcome?
Androcles
sal
No, I know. You also didn't claim to be an American. In fact, you
claimed to eat fish which, PCB's and all, is still a lot better for
you than the standard American diet of beef, french fries, and a thick
shake.
PCB poisoning, if it actually does anything, does it a lot slower than
heart disease. Mercury's another story but you're all grown up so
you probably don't have to worry about that much anyway.
> | > | > I eat what I kill,
> | > |
> | > | Me too, usually. Man those leaves scream when I put 'em in the
> | > | steamer...
> | >
> | > Scream like lobster?
> |
> | Only if you don't shoot the lobster first.
>
> Even if you do, they scream.
> The noise is escaping heated gas coming through crevasses in the
> shell.
For real??
I thought you were just kidding about the lobster. I've never steamed
one, so I wouldn't know, myself (when I was growing up we caught a lot
of crabs but never a lobster).
> I
> didn't know green leaves could scream, though. I learn something new every
> day.
> Are you sure it wasn't the snails on the underside of the cabbage? Ever
> tried steaming lettuce as an experiment?
Yuk. The stuff would turn into mush.
The ones that I generally steam are the ones with a little more "spine"
to them, like kale, spinach, and brocolli.
If you're having any trouble with your eyes you should google those,
by the way, along with whatever your favorite eye disease is. Might
find something useful, you never know.
[ snip ]
> | > You just can't talk to some cats.
> |
> | :-) Indeed. Any cat, actually.
> |
> The one that presently owns me makes his wishes known, I have say "back"
> quite sternly when loading his food dish. He's catching on, though.
> He likes to have a good look inside the refrigerator for the opened can,
> too.
> "Back", I say, to close the fridge door, and he steps back, as soon as he
> sees
> I've got the can.
Uh huh... and how about if you _don't_ have the can?
[ ... ]
> Well.... see, I don't much care for insecticide sprayed green leaves
> myself.
Nor I. So we buy all organic.
Corn's particularly bad that way, since the non-organic corn is all
BT corn these days. You can't wash the insecticide off that stuff,
it's inside the tissues. Of course it's not supposed to hurt people;
it kills the bugs dead but is harmless to mammals. Or so they say.
In this country there's no GMO labelling law so the only way to be
sure what you're buying isn't a GMO is to buy organic.
> I'd rather eat peeled potatoes.
Buy organic, then you don't need to peel them (that crunchy stuff on
the outside's just good clean dirt ... or whatever it is that organic
farmers use for fertilizer ... hmmm....)
> After all, I am British and the
> great delicacy of British cuisine is still the good ol' fish'n'chips that
> I grew
> up with, never has been peanut butter and jelly. But don't let me put you
> off either. Enjoy your crop dusters.
Organic peanut butter, too. And jelly. Mold on the peanuts, yes, no
doubt, but no insecticides (or so they say, anyway; of course it's
what they call a "blind item" which means there is no way for the
consumer to tell if it's really organically grown or not. One reads
the ingredient list and hopes for the best).
> | > How about eggs, those are animal
> | > protein? Ever killed an egg and eaten it? I do, often.
> |
> | Oh, you buy fertile eggs? AFAIK the infertile ones aren't alive but
> | then I've never put one under a microscope to check it out.
>
> They are every bit as fertile as green leaves, and just as alive.
Um ... I can take a green leaf, severed from the plant, no stem at
all, and grow a whole new plant from it. I can do it with a leaf
that's been lying on the floor, unnoticed, behind the desk for a week,
too. (That's a common way to clone jade plants and African violets,
for instance, though one usually skips the 1-week holding period.)
But I never heard that one could take an unfertilized chicken egg and
grow a chicken from it.
> And they go well with bacon...
Well, I will spare the sensibilities of any lurkers here and not go
into details of how they raise pigs (at least in this country).
> Cabbage and bacon for breakfast? Not for me.
Nor me -- I don't eat either one, for the most part.
> | In any case I don't eat the things. Aside from the salmonella (which
> | didn't used to be there) and other nameless diseases spread as a result
> | of the atrocious conditions the chickens are kept in, there's the issue
> | of how they make eggs:
[snip]
> Wouldn't bother me. Ever had black pudding? It's made from pig's
> blood.
I've never had the opportunity to enjoy English cooking.
But these days I stay away from pork ... the conditions on pig farms
in this country have gone from not-so-good to really awful.
> | Except for those rooster chicks, of course, whose deaths are financed by
> | egg sales. When you buy eggs, you're paying somebody to kill the
> | unwanted chicks, but you're not eating those chicks. Hmmm.
>
> Life is a compromise. What is life anyway? What's wrong with raising
> roosters for food?
But they _don't_ raise roosters for food. As I understand it, the
hens grow faster and fatter, so all but a tiny handful of rooster
chicks are just thrown away. (Alive.)
Capon? Nope, they don't sell 'em here, not anymore. The birds on the
shelves are (nearly) all hens.
> Kentucky Fried Rooster sounds ok to me. When I was
> seven years old I was at grandma's house for xmas dinner.
When you were seven years old they hadn't invented factory farmed
chickens yet. All the birds were what we'd call "free range" birds
nowadays.
They didn't feed dead ground-up cows to chickens, and they didn't feed
beef to cows, either. And they didn't load up the birds and the pigs
with antibiotics so they could survive in an environment where they're
packed in so densely that they barely have room to stand up.
The world of farming has changed in the last half-century. It's more
productive in kilos/dollar but it's a lot less esthetic.
> Her sister had
> given her a cock for xmas (her sister raised fertile eggs)
> so we thanked some "Lord" or other for the "bounty" and tucked into cock.
> It tasted like chicken to me, and I said so.
In those days, it was "chicken". Capons were commonly sold, and
they're just like cocks only a bit fatter. I can't recall the last
time I saw a capon for sale.
[ ... ]
> What does sex have to do with resting? You Americans are so mixed up with
> your word usage, it's little wonder you think a dog goes to the bathroom
> in the street and the poor bloody Englishman thinks you're crackers.
:-)
>
>
>
[ snip stuff ]
> |
> | Right -- you've got the rules of inference but until you add a postulate
> | you haven't got much in the way of conclusions.
>
>
> Ah, yes... You are right.
>
> The same laws of audiodacity and acoustics will be valid for all frames
Laws of _what_??
> of reference for which the equations of optics hold good. We will raise
> this conjecture (the purport of which will hereafter be called the
> ``Principle of Relativity'') to the status of a postulate, and also
> introduce another postulate, which is only apparently irreconcilable with
> the former, namely, that sound is always propagated in empty air with a
What's "empty air"? Air which contains no dust, insects, or 747s? Or
is it air that contains no gas? (Typically we call that "vacuum" of
course.)
> definite velocity Mach1 which is independent of the state of motion of the
> emitting noisemaker.
The statement of this postulate seems ambiguous. Unlike vacuum, air
can have a state of motion, and this doesn't say what happens if the
air is in a state of motion relative to the receiver.
If we assume it's supposed to mean the velocity is independent of the
state of motion of the emitter _or_ the air relative to the receiver
then we've got an analogy to relativity.
If we assume it's just supposed to mean the velocity is independent of
the state of motion of the emitter, but that the velocity of the air
affects the measured velocity of the wave, then we've got plain,
ordinary acoustics and there's nothing much about it that's of
interest to this forum. But in that case you also lose the isotropy
of the speed of sound, because if the wind's blowing it's faster in
one direction than the other. But then that would contradict
postulate #1, wouldn't it? So, you must mean it's independent of the
motion of the air as well as the emitter.
> |
> | > Conclusion (after a long drawn out argument you can read for yourself,
> | > just substitute "light" for "sound") :
> | >
> | > gamma = 1/sqrt(1 -v^2/Mach1^2)
> |
> | Sure thing ... as long as you include that assumption that the speed of
> | sound wave is isotropic as measured by all inertial observers.
>
> Huh? Look mate, I've already written the paper without use of the word
> "isotropic"
> or the word "inertial".
> Mirriam Webster says:
> "exhibiting properties with the same values when measured along axes in
> all directions"
> so I guess it's ok.
>
> And
> | that, of course, is equivalent to this assumption:
> |
> | The speed of an object (or wave) traveling at Mach1 is measured as
> | being identical by all inertial observers
> |
> | If you don't include that assumption, or one equivalent to it, then you
> | can't get to that conclusion.
>
> Well, that wouldn't hold, of course.
Yes, I think it _would_ hold. Doppler shift means the observer sees a
frequency shift; it does not need to imply a wave velocity shift.
> Inertial observers can still detect
> doppler shift from the source and know they are moving through air, but I
> have a newer version of Doppler coming right up to make it right.
> 1-cos(phi).v/Mach1
> nu' = nu ----------------------
> sqrt(1-v^2/Mach1^2)
Looks kinda familiar. Might help if phi were defined.
>
> AND I've got
> Mach1 = (Mach1 +v)/(1 + v/Mach1).
>
> Now they know that the speed of sound is measured to be Mach1 in all
> frames
> of reference. I said so.
>
> | > "Now we must bear carefully in mind that a mathematical description
> of
> | > this kind has no physical meaning unless we are quite clear as to
> what we
> | > understand by 'time'. " -- Albert Einstein.
> |
> | Obviously.
> Well then, I defined time, didn't I? You did understand it, I trust?
Sorry, I think I missed that. Could you repeat the definition, please?
>
>
> |
> | > "we establish by definition that the ``time'' required by SOUND to
> travel
> | > from A to B equals the ``time'' it requires to travel from B to
> A. --
> | > Androcles (with tongue in cheek)
> |
> | Sure. But now, with this general statement, you've forced mach1 to be
> | the "universal speed limit" instead of C
>
> Yeah, sure.
> But remember, it is NOT POSSIBLE without further assumption to compare,
> in respect of time, an event at A with an event at B, unless I define
> time the
> way I want to and you agree with me.
>
>
> (or rather you've used the C
> | for sound waves instead of light waves, since traditionally C was any
> | wave velocity).
>
> Well, ok. But since 'C' was usurped by some other bloke to name a
> programming language, I thought I'd specify Mach1.
>
>
>
> | The resulting model will not match our universe in numerous ways,
> | starting with the fact that in your "mach 1" universe, it would take
> | infinite energy to accelerate an airplane to mach 1. That's patently not
> | true here, else the Concord could not have performed as it did.
>
> Concorde never once exceeded Mach1,
Really? So it was all a hoax, after all?
> ask the passengers if they could talk
> to the flight attendants without sounding like they had
> breathed a lungful of helium. The speed of sound inside Concorde was Mach1
> and it performed perfectly well. Air inside, air outside. Want to perform
> MMX on the plane as well? Aether inside, aether outside, and I'm not even
> an
> aetherialist.
> So what is it that is patently not true? It took an enormous amount of
> energy to fly Concorde, which is the main reason it was scrapped.
I thought it was 'cause it was starting to rain Concordes.
> "Now we must bear carefully in mind that a mathematical description of
> this kind has no physical meaning unless we are quite clear as to what
> we
> understand by 'time'. " -- Albert Einstein.
>
> I'm not claiming my mathematical description has physical meaning, I'm not
> THAT stupid. I have a different definition of time, but I'm saving that
> for Newton. Oops... he may have already undsetood it/
>
> Any more objections for me to overcome?
To what? The physical applicability of relativity with C=1100 fps?
No, if you're willing to go so far as to claim the Concorde project
was all just a Big Lie I'll let the case rest (six feet under, where
it belongs).
I am curious, though, how it can be that I see the lightning _before_
I hear the thunder, if nothing can exceed Mach 1. How's the
information about the lightning flash getting to me ahead of the sound
wave in that case?
Androcles
| Oops -- Concorde has an 'e' after all, I see...
Yah... the Frinch had a hand in building it and it wasn't worth
the bothur arguing about its Rolls Royc ingins with the Inglish, who
are somwhat diplomatic.
| > I didn't claim to be a carnivore.
|
| No, I know. You also didn't claim to be an American. In fact, you
| claimed to eat fish which, PCB's and all, is still a lot better for
| you than the standard American diet of beef, french fries, and a thick
| shake.
|
| PCB poisoning, if it actually does anything, does it a lot slower than
| heart disease. Mercury's another story but you're all grown up so
| you probably don't have to worry about that much anyway.
Dunno... when I was a young electrician I found some glass encapsulated
mercury switches that had been broken as a result of closing with a zero
load
(short circuit) heater and it was my job to clean up the spilled mercury
inside
the cabinet.
The switches beat the fuses.
Well, I gathered up the mercury and took it back to the workshop, and in
an idle moment heated it with oxy-acetylene. It vaporized, so I must
have breathed
it in.
| > | > | > I eat what I kill,
| > | > |
| > | > | Me too, usually. Man those leaves scream when I put 'em in
the
| > | > | steamer...
| > | >
| > | > Scream like lobster?
| > |
| > | Only if you don't shoot the lobster first.
| >
| > Even if you do, they scream.
| > The noise is escaping heated gas coming through crevasses in the
| > shell.
|
| For real??
|
| I thought you were just kidding about the lobster. I've never steamed
| one, so I wouldn't know, myself (when I was growing up we caught a lot
| of crabs but never a lobster).
|
Sure for real. Take an inflated toy balloon and stretch the neck into a
straight line
by pinching each side just below the rolled latex, you can make it
vibrate and
control the pitch quite easily. Haven't you seen those inflatable
bladders that
are used as cushions, designed to embarrass your victim by producing a
sound
similar to someone with flatulence when they sit on one?
Then *I* get eaten instead. Cats are carnivores, I daren't risk it.
It happened once and I had to run to the store. The look of reproach
was terrifying.
|
| [ ... ]
|
| > Well.... see, I don't much care for insecticide sprayed green leaves
| > myself.
|
| Nor I. So we buy all organic.
Then you should check this out.
http://www.storewars.org
Now did I say chicken eggs?
Bright green flying elephant's eggs, my friend.
audiodacity (I made that one up from "audacious" plus "audio") and
acoustics.
It's kinda like "electromagnetics" , an insolent term, and "optics".
|
| > of reference for which the equations of optics hold good. We will
raise
| > this conjecture (the purport of which will hereafter be called the
| > ``Principle of Relativity'') to the status of a postulate, and also
| > introduce another postulate, which is only apparently irreconcilable
with
| > the former, namely, that sound is always propagated in empty air
with a
|
| What's "empty air"? Air which contains no dust, insects, or 747s?
Yep. A 747 can ruin a concert and the cleaning staff are forever
sweeping up dust.
| Or is it air that contains no gas?
Some gases are allowed if they are not too aloud.
(Typically we call that "vacuum" of
| course.)
Do you?
Einstein didn't say vacuum, he said "empty space" according to
http://www.fourmilab.ch/etexts/einstein/specrel/www/.
Maybe something was lost in the translation.
Anyway, vacuum doesn't really convey the concept of agoraphobia,
it reminds one of an enclosure of some kind.
Run an electron down a long steel tunnel that is full of vacuum and as
Sue
says, the coulomb coupling with charges in the wall of the tube will
slow
the electron's speed.
I have a similar problem with sound, my ear trumpet only works if it has
a wall of some kind but that funnels mosquitoes into my cochlea, which
is
why I said empty air.
|
|
| > definite velocity Mach1 which is independent of the state of motion
of the
| > emitting noisemaker.
|
| The statement of this postulate seems ambiguous. Unlike vacuum, air
| can have a state of motion, and this doesn't say what happens if the
| air is in a state of motion relative to the receiver.
Vacuum can't move? Surely you jest!
As Sue says, if the train comes to the station then the station comes
to the train. Nothing ambiguous about it, the speed of empty space is
a constant, c, in the inertial frame of reference of the light.
I guess I should have told you about the dynamic reciprocal action of
a conductor and a magnet.
"The observable phenomenon here depends only on the relative motion of
the conductor and the magnet, whereas the customary view draws a sharp
distinction between the two cases in which either the one or the other
of these bodies is in motion. " -Einstein.
I think he borrowed it from Galileo.
"Examples of this sort ... [yada yada yada] ... be called the
``Principle of Relativity''
You wouldn't be taking the customary view and making a distinction,
would you?
But you are correct, the postulate doesn't say what happens if the air
is in a state of motion relative to the receiver. Einstein's postulate
doesn't say what happens if the vacuum is in a state of motion relative
to the receiver either, so no harm, no foul.
What is the speed of light relative to? The empty space.
What is the speed of empty space relative to? The light.
What is the speed of sound relative to? The empty air.
What is the speed of empty air relative to? The sound.
The station comes to the train <=> the train comes to the station.
Dover comes to the ferry <=> the ferry comes to Dover.
The magnet passes the conductor <=> the conductor passes the magnet.
I don't know what happens when a conductor passes a magnet at speed c,
perhaps we adopt the customary view.
| If we assume it's supposed to mean the velocity is independent of the
| state of motion of the emitter _or_ the air relative to the receiver
| then we've got an analogy to relativity.
Assume? Can't do that, sorry.
I carefully copied most of the words, they mean what they say, nothing
more, nothing less.
We have an analogy to SR.
|
| If we assume it's just supposed to mean the velocity is independent of
| the state of motion of the emitter, but that the velocity of the air
| affects the measured velocity of the wave, then we've got plain,
| ordinary acoustics and there's nothing much about it that's of
| interest to this forum.
There ya go again, making assumptions.
| But in that case you also lose the isotropy
| of the speed of sound, because if the wind's blowing it's faster in
| one direction than the other.
| But then that would contradict
| postulate #1, wouldn't it?
Postulate 1 uses an example. The subject of the paragraph is "Example"
[s of this sort]
and the predicate is ``Principle of Relativity'' . Ignore all that guff
about laws for a moment
and concentrate on that.
Predicate: the part of a sentence or clause that expresses what is said
of the subject and that usually consists of a verb with or without
objects, complements, or adverbial modifiers.
Postulate 1 is Galilean Relativity.
The wind doesn't blow, we move relatively to the wind.
You are taking the customary view.
So, you must mean it's independent of the
| motion of the air as well as the emitter.
Of course not.
I said the speed of sound in empty air is Mach1, independent of the
motion
of the source.
I mean what I say, no more, no less.
The empty air moves relatively to the sound at Mach1, per the PoR.
The empty air moves relatively to the observer at v, per the PoR.
The sound moves relative to the observer at Mach1-v, per the PoR and the
vector addition of velocities, which I need to derive gamma and the
composition of velocities, (Mach1+w)/(1 + w/Mach1),
to prove the observer cannot exceed Mach1.
We'd better ask Doppler if there is any shift when the wind blows.
I've a feeling Michelson and Morley were banking on the aether wind
to measure the speed of light as the Earth tore through the aether.
Doppler's answer:
c+v
f' = f-------------
c+u
Where v is the speed of the observer relative to the aether and
u is the speed of the source realtive to the aether, c being the speed
of light
RELATIVE to the aether.
Oh look... no shift if v = u.
Poor old Michelson. He so wanted
c+v
f' = f-------------
c+0
so that he could calculate c.
|
|
| > Inertial observers can still detect
| > doppler shift from the source and know they are moving through air,
but I
| > have a newer version of Doppler coming right up to make it right.
| > 1-cos(phi).v/Mach1
| > nu' = nu ----------------------
| > sqrt(1-v^2/Mach1^2)
|
| Looks kinda familiar. Might help if phi were defined.
|
Yeah... but a smart guy like you should be able to figure it out.
Disregard the denominator, so that
nu' = nu * [ 1-cos(phi).v/Mach1]
= nu * [ Mach1 / Mach1 -cos(phi).v/Mach1]
Then let phi = 0, so that cos(0)= 1
nu' = nu * [ Mach1 / Mach1 - v/Mach1]
Mach1 - v
nu' = nu ------------------
Mach1
Then let phi = 180, so that cos(phi) = -1.
Mach1 + v
nu' = nu ------------------
Mach1
which is equivalent to
c+v
f' = f-------------
c+0
So if you run from the source you get red shift and toward the source,
no shift. Let phi = 90 or -90, cos(phi) = 0, no transverse shift.
|
| >
| > AND I've got
| > Mach1 = (Mach1 +v)/(1 + v/Mach1).
| >
| > Now they know that the speed of sound is measured to be Mach1 in all
| > frames
| > of reference. I said so.
| >
| > | > "Now we must bear carefully in mind that a mathematical
description
| > of
| > | > this kind has no physical meaning unless we are quite clear as
to
| > what we
| > | > understand by 'time'. " -- Albert Einstein.
| > |
| > | Obviously.
| > Well then, I defined time, didn't I? You did understand it, I trust?
|
| Sorry, I think I missed that. Could you repeat the definition,
please?
Sure.
The ``time'' required by SOUND to travel from A to B equals the ``time''
it requires to travel from B to A.
The ``time'' required by SOUND to travel from A to B equals the ``time''
it requires to travel from B to A.
The ``time'' required by SOUND to travel from A to B equals the ``time''
Of course. Mach1 = (Mach1 +w)/(1+w/Mach1)
If you have two Concordes crossing the Atlantic and going
in opposite directions their closing speed is given by
V = (v+w)/(1+vw/Mach1), and you can forget that conductor passing
a magnet, too.
The magnet that moves though air, the conductor being stationary, has a
different result to the conductor moving and the magnet stationary.
It was only a first order approximation anyway.
Along with relativity?
| I am curious, though, how it can be that I see the lightning _before_
| I hear the thunder, if nothing can exceed Mach 1. How's the
| information about the lightning flash getting to me ahead of the sound
| wave in that case?
"it is not possible without further assumption to compare, in respect of
time, an event at A with an event at B."
Androcles.
Henri Wilson
>On Wed, 20 Jul 2005 03:59:36 +0000, Androcles wrote:
>
>>
>> "Henri Wilson" <H@..> wrote in message
>>| I used to fish a great deal. Gave it up about ten years ago when I
>>| realised fish don't particularly like being dragged out of the water
>>| with a bloody big hook stuck in their palates.
>>| Still I guess they don't like being bitten in half or swallowed whole
>>| by bigger fish either.
>>| The only things I fish out of creeks now are golf balls.
>
>Yeah, I can go along with that. I gave up fishing about 30 years ago.
>
>
>> | >| I agree, I was only trying to force the SRians to reluctantly agree
>> | >| with someting I said .
>
>Hey, I just did. Does that count?
No. Only 80%
I believe we are still omnivores whether we like it or not.
The canines dropped out after we invented cutting tools.
sal
On Sat, 23 Jul 2005 15:02:48 +0000, Androcles wrote:
>
> "sal" <pragm...@nospam.org> wrote in message
> news:pan.2005.07.23....@nospam.org...
> | > Well.... see, I don't much care for insecticide sprayed green
> | > leaves myself.
> |
> | Nor I. So we buy all organic.
>
> Then you should check this out.
> http://www.storewars.org
:-)
> | > They [eggs] are every bit as fertile as green leaves, and just
> | > as alive.
> | Um ... I can take a green leaf, severed from the plant, no stem at
> | all, and grow a whole new plant from it. I can do it with a leaf
> | that's been lying on the floor, unnoticed, behind the desk for a
> | week, too. (That's a common way to clone jade plants and African
> | violets, for instance, though one usually skips the 1-week holding
> | period.) But I never heard that one could take an unfertilized
> | chicken egg and grow a chicken from it.
>
> Now did I say chicken eggs? Bright green flying elephant's eggs, my
> friend.
What? You can grow a whole chicken from an elephant egg??
That was a hundred years ago. We've advanced since then. Now we have
a name for "empty space": we call it "vacuum".
Anyway, his space wasn't really empty, because he had light rays
passing through it.
> Anyway, vacuum doesn't really convey the concept of agoraphobia, it
> reminds one of an enclosure of some kind. Run an electron down a
> long steel tunnel that is full of vacuum and as Sue says,
AFAICT Sue says whatever is needed to keep the argument going. She/he
seems to enjoy arguing, regardless of what side she/he is on. You're
a little easier to argue with than Sue: I always know which side
you're going to come down on.
> the coulomb coupling with charges in the wall of the tube will slow
> the electron's speed.
I don't know about coulomb coupling, but it might induce some eddy
currents in the walls, in which case it should slow down if we like
conservation of energy. But in any case, whether there's radiation
present may be frame dependent.
Does an electron falling toward the Earth radiate?
> I have a similar problem with sound, my ear trumpet only works if it
> has a wall of some kind but that funnels mosquitoes into my cochlea,
> which is why I said empty air.
If you squash them after they get stuck in your cochlea, you should
eat them afterwards, just to be consistent.
> | The statement of this postulate seems ambiguous. Unlike vacuum,
> | air can have a state of motion, and this doesn't say what happens
> | if the air is in a state of motion relative to the receiver.
>
> Vacuum can't move? Surely you jest!
No, vacuum can't move.
> As Sue says,
Sue says whatever is needed to keep the argument going.
> if the train comes to the station then the station comes to
> the train.
Does the train stop at the station? Then it must have decelerated.
Did the station decelerate, too? Nope, not as a rule. So, the
situation isn't symmetric, and it's not really correct to say the
station "comes into the train".
In any case "comes into" suggests containment, and while the train may
be contained in the station the reverse is never true.
> Nothing ambiguous about it, the speed of empty space is a constant,
> c, in the inertial frame of reference of the light.
Light has no inertial frame in relativity.
In emission theory its velocity isn't fixed so the speed of "empty
space" wouldn't be fixed either.
> I guess I should have told you about the dynamic reciprocal action
> of a conductor and a magnet. "The observable phenomenon here
> depends only on the relative motion of the conductor and the magnet,
> whereas the customary view draws a sharp distinction between the two
> cases in which either the one or the other of these bodies is in
> motion. " -Einstein. I think he borrowed it from Galileo.
Constant linear motion is relative. Acceleration OTOH is absolute.
> "Examples of this sort ... [yada yada yada] ... be called the
> ``Principle of Relativity''
>
> You wouldn't be taking the customary view and making a distinction,
> would you?
No, I'm pointing out that in relativity theory, VACUUM has no
velocity. Only observers and observables move. There is nothing
about vacuum that can be observed so it's meaningless to talk about
its velocity.
FIELDS have no velocity, either. A magnetic or electric field just
"is". Its value at a particular point can change as time passes, but
the field doesn't "move". That includes the fields in "traveling
waves" such as light and radio: when you look at the equations to see
what's going on, there's nonzero dE/dt and nonzero dB/dt and there's a
velocity associated with the maxima and minima in the fields, but the
fields themselves aren't described as "moving".
Energy moves, and the Pointing vector says where it's going when it's
the energy of the E and B fields. Momentum moves. But the fields
themselves don't "move".
An electron, stationary in a particular FoR, does _not_ react to any B
field as measured in that FoR, because the B fields don't "move"
relative to the electron. However, electrons _are_ observed to
respond to B fields when the electrons are moving relative to an
observer in a frame of reference in which there is a nonzero B field.
There is a lot of confusion on this point, even in reasonably
reputable textbooks.
Air, on the other hand, has properties that allow one to sensibly
talk about its motion.
> But you are correct, the postulate doesn't say what happens if the
> air is in a state of motion relative to the receiver. Einstein's
> postulate doesn't say what happens if the vacuum is in a state of
> motion relative to the receiver either,
As I said, vacuum can't "move". Air can.
> so no harm, no foul. What is the speed of light relative to? The
> empty space.
Nope, it's relative to an observer. After it's emitted, the emitter
can (in principle) measure its velocity, too, and hence "observe" it,
so the emitter also qualifies as an "observer". Vacuum can't observe
anything, and has no properties that let you assign a velocity to it,
so we can't talk about the velocity of the light relative to the
vacuum.
If a tree falls in a forest and there's no one to hear it, does it
make a sound?
If light passes through vacuum in an otherwise empty universe, how
fast does it go? That's a question without an answer.
> What is the speed of empty space relative to? The light. What is the
> speed of sound relative to? The empty air. What is the speed of
> empty air relative to? The sound. The station comes to the train <=>
> the train comes to the station. Dover comes to the ferry <=> the
> ferry comes to Dover. The magnet passes the conductor <=> the
> conductor passes the magnet. I don't know what happens when a
> conductor passes a magnet at speed c,
It melts.
> perhaps we adopt the customary view.
>
>
> | If we assume it's supposed to mean the velocity is independent of
> | the state of motion of the emitter _or_ the air relative to the
> | receiver then we've got an analogy to relativity.
>
> Assume? Can't do that, sorry.
How about "guess"?
Again, that works for air, because we can measure how fast it's going
relative to other things. It doesn't work for vacuum, which has no
velocity.
How do you build an anemometer that shows how fast vacuum is going?
[snip a bunch of stuff ]
> We'd better ask Doppler if there is any shift when the wind
> blows. I've a feeling Michelson and Morley were banking on the
> aether wind to measure the speed of light as the Earth tore through
> the aether.
Aether! Ah, that's a different subject!
You can talk about how fast the aether is moving, and discuss what
properties of it might let you measure its velocity. But aether is
not vacuum.
> Doppler's answer:
> c+v
> f' = f-------------
> c+u
>
> Where v is the speed of the observer relative to the aether and u is
> the speed of the source realtive to the aether, c being the speed of
> light RELATIVE to the aether. Oh look... no shift if v = u.
>
> Poor old Michelson. He so wanted
> c+v
> f' = f-------------
> c+0
> so that he could calculate c.
Whatever ... I've never read any papers by Doppler.
So phi's an angle. Which angle is it?
Angle between the emitted ray, or the received ray, and ... what?
There's more than one way to set it up and the answers are different
depending on how you do it.
> | > AND I've got
> | > Mach1 = (Mach1 +v)/(1 + v/Mach1).
> | >
> | > Now they know that the speed of sound is measured to be Mach1 in all
> | > frames
> | > of reference. I said so.
> | >
> | > | >
> | > | > "Now we must bear carefully in mind that a mathematical
> | > | > description of this kind has no physical meaning unless we
> | > | > are quite clear as to what we understand by 'time'. " --
> | > | > Albert Einstein.
> | > |
> | > | Obviously.
> | > Well then, I defined time, didn't I? You did understand it, I
> | > trust?
> |
> | Sorry, I think I missed that. Could you repeat the definition,
> please?
> Sure.
> The ``time'' required by SOUND to travel from A to B equals the ``time''
> it requires to travel from B to A.
> The ``time'' required by SOUND to travel from A to B equals the ``time''
> it requires to travel from B to A.
> The ``time'' required by SOUND to travel from A to B equals the ``time''
> it requires to travel from B to A.
Sorry, that doesn't define "time", it just tells me how it behaves in
one very specific case.
[ snip ]
> | > Concorde never once exceeded Mach1,
> |
> | Really? So it was all a hoax, after all?
>
> Of course. Mach1 = (Mach1 +w)/(1+w/Mach1) If you have two Concordes
> crossing the Atlantic and going in opposite directions their closing
> speed is given by V = (v+w)/(1+vw/Mach1),
What are they doing, playing "chicken"?
OK, I've got a question for you.
How do you handle the Sagnac effect in emission theory?
Do you deny it exists (as Henri seems to do when pressed), or do you
have an explanation for it?
Just curious.
--
Nospam becomes physicsinsights to fix the email
I can be also contacted through http://www.physicsinsights.org
Androcles
| 650 lines ... some snipping is needed here.
Ok, I'll snip what I've read and answered.
I won't snip anything I didn't answer.
| On Sat, 23 Jul 2005 15:02:48 +0000, Androcles wrote:
|
| >
| > Now did I say chicken eggs? Bright green flying elephant's eggs, my
| > friend.
|
| What? You can grow a whole chicken from an elephant egg??
Nope. You can grow a whole bright green flying elephant from a
bright green flying elephant's egg, though. You need a black hole
or wormhole in spacetime to incubate them in, but there are plenty
of those around. I saw a black hole being discussed not too long ago,
on this very newsgroup.
You know what FIFO is?
Some peope mistake it it for 'first in, first out', but that's garbage.
It's actually 'fiction in, fiction out'.
|
| > | [ snip stuff (and more stuff) ]
| > Einstein didn't say vacuum, he said "empty space" according to
| > http://www.fourmilab.ch/etexts/einstein/specrel/www/. Maybe
something was
| > lost in the translation.
|
| That was a hundred years ago. We've advanced since then. Now we have
| a name for "empty space": we call it "vacuum".
Ah.... That must be like McCullough the relativist.
He says a closing velocity is different to a relative velocity.
c-v is a closing velocity, (c+w)/(1+ w/c) is a relative velocity.
Einstein called c-v a relative velocity, but that was 100 years ago.
What did he know, huh?
Maybe it's the 'w' instead of the 'v'...
You can't derive the Lorentz Transforms without a closing velocity.
"But the ray moves relatively to the initial point of k,
when measured in the stationary system, with the velocity
c-v..." -Einstein.
What did he know, huh?
Should'a said
"But the ray moves CLOSINGLY to the initial point of k,
when measured in the stationary system, with the velocity c-v...",
right?
I dunno why it isn't an opening velocity, the light is running away
from the initial point of k at c-v, but maybe we'll change it in 100
years.
| Anyway, his space wasn't really empty, because he had light rays
| passing through it.
True, true.
My air isn't really empty either, it has sonic beams passing through it.
|
| > Anyway, vacuum doesn't really convey the concept of agoraphobia, it
| > reminds one of an enclosure of some kind. Run an electron down a
| > long steel tunnel that is full of vacuum and as Sue says,
|
| AFAICT Sue says whatever is needed to keep the argument going. She/he
| seems to enjoy arguing, regardless of what side she/he is on. You're
| a little easier to argue with than Sue: I always know which side
| you're going to come down on.
Ah, but I don't give up. I pay attention and reply. I never know when
you are going to ignore a point I make and pretend it isn't there.
|
|
| > the coulomb coupling with charges in the wall of the tube will slow
| > the electron's speed.
|
| I don't know about coulomb coupling, but it might induce some eddy
| currents in the walls, in which case it should slow down if we like
| conservation of energy. But in any case, whether there's radiation
| present may be frame dependent.
|
| Does an electron falling toward the Earth radiate?
I think it's called Cherenkov radiation, but you only get it in a
medium.
A good example might be the Aurora Borealis...
Look on the ground underneath the lights, you may find some dead
muons as well. They are not easy to see, they are white and all that
snow camouflages them. The electrons are easier to spot. They are blue
with little minus signs painted on the side.
Red balls might be snooker balls, return those to the billard table.
| > I have a similar problem with sound, my ear trumpet only works if it
| > has a wall of some kind but that funnels mosquitoes into my cochlea,
| > which is why I said empty air.
|
| If you squash them after they get stuck in your cochlea, you should
| eat them afterwards, just to be consistent.
Oh, I do! I prefer to keep then out, though. The doctor said they
contain "bad air", or mal-aria, and then he wants to stick needles in
me.
| > | The statement of this postulate seems ambiguous. Unlike vacuum,
| > | air can have a state of motion, and this doesn't say what happens
| > | if the air is in a state of motion relative to the receiver.
| >
| > Vacuum can't move? Surely you jest!
|
| No, vacuum can't move.
Who says so?
|
|
| > As Sue says,
|
| Sue says whatever is needed to keep the argument going.
|
|
| > if the train comes to the station then the station comes to
| > the train.
|
| Does the train stop at the station?
Nope. It was an express.
"Calling all stations, Chatham, Rochester, Strood, Higham.."
thats a slow train to Charing Cross.
The fast train to Victoria only stops at Chatham, Bromley South
and Victoria.
I can tell you've never travelled on a train.
Then it must have decelerated.
| Did the station decelerate, too? Nope, not as a rule.
Aww... so there IS a universal absolute frame of reference after all?
Maybe that's where the universal master clock is...
I think Ernst Mach might shed some sound on it, do you?
http://en.wikipedia.org/wiki/Image:Ernstmach.jpg
So, the
| situation isn't symmetric, and it's not really correct to say the
| station "comes into the train".
I guess we'd better let Galileo and Ernst battle that one out.
Isaac and Albert should be in on it too. Isaac reckons there is
something funny about stirring coffee, it rises to the sides of the
mug no matter which way you stir the sugar in. You probably don't
take sugar... or even coffee...
Maybe the entire universe is spinning around the mug's contents...
Albert has his magnet and conductor that seem to follow Galileo...
Whatever, I'm out of my depth, this is too much empirical data
for me.
You are a follower of the Albert school of thought, are you not?
|
| In any case "comes into" suggests containment, and while the train may
| be contained in the station the reverse is never true.
|
| > Nothing ambiguous about it, the speed of empty space is a constant,
| > c, in the inertial frame of reference of the light.
|
| Light has no inertial frame in relativity.
Forgot about it, huh? Oversights can be forgiven.
| In emission theory its velocity isn't fixed so the speed of "empty
| space" wouldn't be fixed either.
Well of course.
In emission theory we adhere to the magnet and conductor Albert
told us about and called the PoR. Ernst and Isaac's coffee spills
over the side of the mug, which is why brandy snifters were invented.
I think I'll side with Ernst and Isaac, I like brandy. I still like that
magnet and conductor though... pity Albert denied it and called
it a first order approximation... I can't help wondering whether
we get cheaper electricity by spinning a magnet in a rotor with a
conductor in the stator or the other way around.
As you say, the situation isn't symmetric, and it's not really correct
to say the magnet "comes into the conductor" or even
"the conductor comes into the magnet."
What the [train] conductor should say is "Fare please",
or "FAIR, please", as they do on British Rail.
Sue didn't say "into", you made that one up. Be 'fare' and pay up.
You owe me one snifter of brandy, I've caught you cheating.
You can try to win it back, but you'll have to be 'goddamn' sharp.
I learnt that in Pittsburgh... "God bless goddamn America!";
Yonko, who said that, was a nice old guy.
76 years of age, still working and still putting his son through
college at over 40 years of age.
I could only shake my head and remain silent.
Yonko had a stroke... I never saw him again.
Shoulda been the useless son in his stead.
Oh well, Yonko loved him, who am I to judge another?
Makes me weep though, goddammit!
| > I guess I should have told you about the dynamic reciprocal action
| > of a conductor and a magnet. "The observable phenomenon here
| > depends only on the relative motion of the conductor and the magnet,
| > whereas the customary view draws a sharp distinction between the two
| > cases in which either the one or the other of these bodies is in
| > motion. " -Einstein. I think he borrowed it from Galileo.
|
| Constant linear motion is relative. Acceleration OTOH is absolute.
That's Sue's "station comes to the train", not Steve's "station comes
INTO the train can't happen."
You owe me a brandy, and I think Sue deserves one too.
I'll agree d^2x/dt^2 is absolute. (For now).
't' better be absolute also. x can be anything it likes or you like.
Isaac and Galileo will agree with me. Albert will not. Dunno about
Ernst or you, but its 3:2 already. I'd prefer 4:1.
Or did you want to bring in your pal, (what's his name? )
Orentz, or something? Laurence, that's it! Or is it Lawrence...
I forget.
Anyway, do that and I'll bring Johannes Kepler. Not Johannes
Brahms, although he's a good musician.
|
| > "Examples of this sort ... [yada yada yada] ... be called the
| > ``Principle of Relativity''
| >
| > You wouldn't be taking the customary view and making a distinction,
| > would you?
|
| No, I'm pointing out that in relativity theory, VACUUM has no
| velocity. Only observers and observables move. There is nothing
| about vacuum that can be observed so it's meaningless to talk about
| its velocity.
I'd almost agree with you, but that conductor and magnet still
bother me, almost as much as "light is always propagated in empty
space with a definite velocity c "... I can't help wondering what
the speed (or velocity) of [light without a frame] is being compared to.
It's pretty easy with the magnet moving INTO the conductor or the
conductor moving INTO the magnet, because I think there is some
kind of "aura" around the magnet, "lines of fours" I think it's called.
And another one, called an electric field. Do electrics graze there like
cattle in a meadow? How about an electric meadow?
|
| FIELDS have no velocity, either. A magnetic or electric field just
| "is".
Oh, I agree. Whole-heartedly and with tongue in cheek.
Radio doesn't work.
Wanna bring in Maxwell and Hertz as well?
| Its value at a particular point can change as time passes, but
| the field doesn't "move". That includes the fields in "traveling
| waves" such as light and radio: when you look at the equations to see
| what's going on, there's nonzero dE/dt and nonzero dB/dt and there's a
| velocity associated with the maxima and minima in the fields, but the
| fields themselves aren't described as "moving".
Fixed in the absolute frame of reference called vacuum, huh?
I think Ernst will agree with you, and Isaac wants an absolute time.
Maybe there IS a difference between the motion of a magnet past
a conductor and the motion of a conductor past a magnet... Hmmm?
Tell ya what!! Let's see what happens when we accelerate one
past the other and the other past one. I happen to think the magnet
takes its field along for the ride, but what do I know? Only way
to find out is experiment, I could be wrong.
|
| Energy moves, and the Pointing vector says where it's going when it's
| the energy of the E and B fields. Momentum moves. But the fields
| themselves don't "move".
Ok. Magnets don't move, if you say so. I must have moved my
fridge to the magnet. I hope you notice I'm not arguing with you.
I'm hanging on your every word. It was my fridge that accelerated
and decelerated, but the station doesn't come into the train and the
fridge doesn't go into the magnet.
| An electron, stationary in a particular FoR, does _not_ react to any B
| field as measured in that FoR, because the B fields don't "move"
| relative to the electron.
Quite so. The fridge comes to the magnet and the train comes into
the station. I fully understand.
However, electrons _are_ observed to
| respond to B fields when the electrons are moving relative to an
| observer in a frame of reference in which there is a nonzero B field.
Weelllllll... have you consider that electrons don't have frames of
reference? Light doesn't, so maybe they don't either.
"Without affecting the general character of our considerations, we may
and will assume that the electron, at the moment when we give it our
attention, is at the origin of the co-ordinates, and moves with the
velocity v along the axis of X of the system K. It is then clear that at
the given moment (t=0) the electron is at rest relatively to a system of
co-ordinates which is in parallel motion with velocity v along the axis
of X."
Excerpt from "Dynamics of the Slowly Accelerated Electron" by Albert
Einstein.
Looks like you are right... the conductor moves and the magnet doesn't.
I'll make sure I use slip rings on the rotor and a magnetic stator next
time I design a generator.
| There is a lot of confusion on this point, even in reasonably
| reputable textbooks.
Oh, I'm sure there is. Even I'm confused, I could have sworn
my bicycle used a moving magnet to power the lights.
Maybe the bike goes around the wheels, huh?
| Air, on the other hand, has properties that allow one to sensibly
| talk about its motion.
Of course. The plane flies INTO the air, the kitchen window blows
INTO the wind. Air has no motion. See how agreeable I am?
|
| > But you are correct, the postulate doesn't say what happens if the
| > air is in a state of motion relative to the receiver. Einstein's
| > postulate doesn't say what happens if the vacuum is in a state of
| > motion relative to the receiver either,
|
| As I said, vacuum can't "move". Air can.
Ah, but it doesn't. It COULD, but the plane flies INTO the air,
like the train comes INTO the station. The air doesn't come
to the plane (of course). The plane accelerated and so did the
house when it only seemed the wind was blowing through the
kitchen window.
|
| > so no harm, no foul. What is the speed of light relative to? The
| > empty space.
|
| Nope, it's relative to an observer.
That's not what Albert said. He didn't mention any observer in
his second postulate. Maybe you have some other theory that
isn't Albert's. Has it been published? I'd like to read it.
I can't discuss some other theory until I've read it, sorry.
After it's emitted, the emitter
| can (in principle) measure its velocity, too, and hence "observe" it,
| so the emitter also qualifies as an "observer". Vacuum can't observe
| anything, and has no properties that let you assign a velocity to it,
| so we can't talk about the velocity of the light relative to the
| vacuum.
We can't? Albert said it was c in empty space. I'm confused.
Maybe you have some other theory I haven't read. I'm discussing
"On the Electrodynamics of Moving Bodies", by Albert Enstein,
not "Harry Potter and the Sorcerer's Stone" by Joanna Rowling.
Both are great fiction, but I'm not sure which you are referring to.
Maybe I missed a passage in Joanna's book.... I didn't in Albert's.
|
| If a tree falls in a forest and there's no one to hear it, does it
| make a sound?
I'm defining "sound" as vibrations in air, which is objective.
You can't define "sound" as something heard, there was never anyone
to hear, even subjectively.
So yes, there is a sound by my definition of "sound".
TWO brandies now, I've caught you.
Interesting observation, though. The subjective relativist thinks
light is something percieved and has a speed relative to him personally,
the objective scientist thinks light exists even without him.
The trees are falling in the forest all the time, the stars are emitting
light
continually and will continue long after my demise as they did before
my birth. My experience will be oblivion before and after my existence.
Rene desCartes thought, therefore he was. He doesn't think today,
therefore he isn't.
| If light passes through vacuum in an otherwise empty universe, how
| fast does it go? That's a question without an answer.
I'll agree with you on that point, therefore I'll disagree with Albert.
I refuse to make the switch from 'empty space' to 'observer', though.
It's subjective.
I'll stick with 'source', along with Galileo Galilei. He was the father
of modern
science, and he was objective. I'll stick with Newton and William of
Ockham,
too, http://www.csse.monash.edu.au/~lloyd/tildeImages/People/Ockham/
and Copernicus who use relativity for his heliocentric universe in place
of the subjective geocentric view of Ptolemy.
It's pretty wild, really.
The sun crosses the sky daily but doesn't orbit the Earth.
The moon crosses nightly and does orbit the Earth.
The Earth moves? Incredible, I can't feel a thing.
What's a poor farmer to believe?
The speed of light is observer dependent? Of course!
It must be, sal said so and he's got all of Albert's math.
Isaac would be curious, then rewrite it so that it made objective
sense. Both would love to see V1493 Aql explained, though, and
Albert can't offer anything. Androcles can, he has a computer.
William of Ockham would dismiss Albert in the blink of an eye.
| > I don't know what happens when a
| > conductor passes a magnet at speed c,
|
| It melts.
Generators can get quite warm, that's for sure.
I though an electron beam in a monitor tube was a current that was
deflected by a magnetic field as they moved past it.
Electrons melt? I didn't know that.
Still, I guess you know.
Maybe the electrons melt the vacuum, huh? Or do they turn through
90 degrees and head off toward the pole of the magnet? Nah...
too much inertia... They must melt.
|
| > perhaps we adopt the customary view.
| >
| >
| > | If we assume it's supposed to mean the velocity is independent of
| > | the state of m
otion of the emitter _or_ the air relative to the
| > | receiver then we've got an analogy to relativity.
| >
| > Assume? Can't do that, sorry.
|
| How about "guess"?
Not science, old chap. I like melting electrons, they form a gooey
paste when they run together.
The air doesn't move. The train can come into the station, but has
to decelerate. The station doesn't accelerate or decelerate, remember?
Air can't either, it covers the entire globe. If it accelerated, it
would have
to move, and if it moved it would disappear down a Chinese coal mine
and come back up through a Pennsylvania coal mine (or the other way
round).
The plane flies INTO the air, so does the kitchen window if you leave
it open.
|
| How do you build an anemometer that shows how fast vacuum is going?
Dunno... I'll have to think about it.
I agreed with you and not with Albert. Vacuum can't move.
How do you measure the speed of light in a vacuum to test
Albert's second postulate? You'll have to make sure the vacuum isn't
moving, right? If it moved it might carry the light along with it,
like a river carries a boat downstream. Sue reckons the vacuum
has the properties of permittivity and permeability, she loves to
talk about those. Keeps talking about alpha and mu0...
I don't think they exist. mu1, maybe.
| [snip a bunch of stuff ]
|
| > We'd better ask Doppler if there is any shift when the wind
| > blows. I've a feeling Michelson and Morley were banking on the
| > aether wind to measure the speed of light as the Earth tore through
| > the aether.
|
| Aether! Ah, that's a different subject!
Well, yeah...and ectoplasm...
|
| You can talk about how fast the aether is moving, and discuss what
| properties of it might let you measure its velocity. But aether is
| not vacuum.
Right enough, nor is ectoplasm. It's amazing what some people
will come up with.
|
|
| > Doppler's answer:
| > c+v
| > f' = f-------------
| > c+u
| >
| > Where v is the speed of the observer relative to the aether and u is
| > the speed of the source realtive to the aether, c being the speed of
| > light RELATIVE to the aether. Oh look... no shift if v = u.
| >
| > Poor old Michelson. He so wanted
| > c+v
| > f' = f-------------
| > c+0
| > so that he could calculate c.
|
| Whatever ... I've never read any papers by Doppler.
Aww... I don't understand German either.
Here's one by Russell, talking about Doppler.
http://www.kettering.edu/~drussell/Demos/doppler/doppler.html
Well it would be, it's an argument to a cosine function.
It's somewhere between 0 and 360 degrees, I think.
But it should work above and below that and the cosine
function should yield between -1 and +1.
|
| Angle between the emitted ray, or the received ray, and ... what?
| There's more than one way to set it up and the answers are different
| depending on how you do it.
Yep. I tried to tell Albert that very same thing. In the end I had
to figure out what he meant. He didn't put cos(phi) in
beta = 1/ sqrt(1 - [v.cos(phi)/c]^2) either.
Maybe he overlooked it.
You'd better tell Albert, then. He uses that stuff you call "light" to
replace my "sound".
Personally I think it is rather daft, but you can't have time dilation
without it. Remember that horrible equation we discussed?
―[tau(0,0,0,t)+tau(0,0,0,t+x'/(c-v)+x'/(c+v))] = tau(x',0,0,t+x'/(c-v))
?
That '―' is there to compute the time it takes for light to go from
A to B. The round trip from A to B and back again cut in half.
I'm using sound instead. I cribbed from Albert. Naughty of me.
|
| [ snip ]
|
| > | > Concorde never once exceeded Mach1,
| > |
| > | Really? So it was all a hoax, after all?
| >
| > Of course. Mach1 = (Mach1 +w)/(1+w/Mach1) If you have two Concordes
| > crossing the Atlantic and going in opposite directions their closing
| > speed is given by V = (v+w)/(1+vw/Mach1),
|
| What are they doing, playing "chicken"?
|
|
| OK, I've got a question for you.
|
| How do you handle the Sagnac effect in emission theory?
Emission theory is only about light in EMPTY space. Sagnac space
isn't empty.
My new "sound" theory with built-in time dilation isn't emission
theory either. Looks like you snipped it, though.
What you need is the older "medium" theory. Sue is much
more familiar with mus and alphas and permeabilities and such.
Sorry to pass the buck, but light in a medium isn't my specialty.
It has the speed of c/n relative to the medium, 'n' being the refractive
index. It isn't source dependent anymore once it leaves the vacuum.
|
| Do you deny it exists (as Henri seems to do when pressed), or do you
| have an explanation for it?
|
| Just curious.
Good grief no. I NEVER deny empirical data.
I deny impossible theories with badly thought out mathematics.
I've tried to tell you about the errors before, but you quickly lose
interest and snip what doesn't agree with your stomach.
Androcles.
sal
>
> "sal" <pragm...@nospam.org> wrote in message
> news:pan.2005.07.25....@nospam.org...
> | 650 lines ... some snipping is needed here.
>
> Ok, I'll snip what I've read and answered. I won't snip anything I
> didn't answer.
>
> | On Sat, 23 Jul 2005 15:02:48 +0000, Androcles wrote:
> |
> |
> | > Now did I say chicken eggs? Bright green flying elephant's
> | > eggs, my friend.
> |
> | What? You can grow a whole chicken from an elephant egg??
>
> Nope. You can grow a whole bright green flying elephant from a
> bright green flying elephant's egg, though. You need a black hole or
> wormhole in spacetime to incubate them in, but there are plenty of
> those around. I saw a black hole being discussed not too long ago,
> on this very newsgroup. You know what FIFO is? Some peope mistake
> it it for 'first in, first out', but that's garbage. It's actually
> 'fiction in, fiction out'.
On this side of the Atlantic we use GIGO for the latter: Garbage in,
garbage out. FIFO is reserved for a queue.
> | [ snip stuff (and more stuff) ]
>
> | > Einstein didn't say vacuum, he said "empty space" according to
> | > http://www.fourmilab.ch/etexts/einstein/specrel/www/. Maybe
> | > something was lost in the translation.
> |
> | That was a hundred years ago. We've advanced since then. Now we
> | have a name for "empty space": we call it "vacuum".
>
> Ah.... That must be like McCullough the relativist. He says a
> closing velocity is different to a relative velocity.
This is semantic logic-chopping, really. Relative velocity, closing
velocity -- either one works for me. Either way, it's the time
derivative of a length, rather than the time derivative of the
location of an object, and as such it's not a "velocity" at all in the
sense that it doesn't tell you how fast something's going.
If two cars collide head-on, each going 60 MPH (which is legal again
in this country), then as viewed by an observer by the side of the
road each car had speed = 60 MPH (and velocity = +/- 60 depending on
the direction, if we use the convention that speed = abs(velocity)).
The "closing speed" or "relative speed" or whatever you want to call
it is 120 MPH, but it's not the velocity of any object, as viewed by
our roadside observer, because it's not the derivative of a position.
The time derivative of the X coordinate of car A is (let's say) +60
MPH, and the time derivative of the X coordinate of car B is -60 MPH.
Those are both velocities. But the time derivative of the _difference_
between their X coordinates is -120 MPH, and as I already said it's
not what we usually mean by a "velocity".
I think one of us here may be an Einstein fetishist but it's not me.
(How much time have _you_ spent studying his words? More time than
me, I suspect very strongly!) I also happen to think his language in
the electrodynamics paper was not exactly crystal clear.
> c-v is a
> closing velocity, (c+w)/(1+ w/c) is a relative velocity.
If you want to define it that way go ahead but it sounds like a really
confusing use of the language to me.
> Einstein
> called c-v a relative velocity, but that was 100 years ago. What did
> he know, huh? Maybe it's the 'w' instead of the 'v'... You can't
> derive the Lorentz Transforms without a closing velocity.
> "But the ray moves relatively to the initial point of k,
> when measured in the stationary system, with the velocity c-v..."
> -Einstein.
> What did he know, huh?
> Should'a said "But the ray moves CLOSINGLY to the initial point of
> k, when measured in the stationary system, with the velocity
> c-v...", right? I dunno why it isn't an opening velocity, the light
> is running away from the initial point of k at c-v, but maybe we'll
> change it in 100 years.
I like the term "opening velocity". I've even used it in some post or
other.
Either way it's just a nit in his language which doesn't have much of
anything to do with the actual meaning of the quantity in question,
which is a time derivative of the difference between two space
coordinates.
> | Anyway, his space wasn't really empty, because he had light rays
> | passing through it.
>
>
> True, true.
> My air isn't really empty either, it has sonic beams passing through
> it.
And according to relativity theory sonic beams have mass, since they
carry energy....
> | > Anyway, vacuum doesn't really convey the concept of agoraphobia,
> | > it reminds one of an enclosure of some kind. Run an electron
> | > down a long steel tunnel that is full of vacuum and as Sue says,
> |
> | AFAICT Sue says whatever is needed to keep the argument going.
> | She/he seems to enjoy arguing, regardless of what side she/he is
> | on. You're a little easier to argue with than Sue: I always know
> | which side you're going to come down on.
>
> Ah, but I don't give up.
So why did you take your website down, anyway?
> I pay attention and reply. I never know
> when you are going to ignore a point I make and pretend it isn't
> there.
When I get bored, and run short on time.
Hard to tell from the outside when that point is, of course (you're
dealing with a "black box" model, in some sense).
> | > the coulomb coupling with charges in the wall of the tube will
> | > slow the electron's speed.
> |
> | I don't know about coulomb coupling, but it might induce some eddy
> | currents in the walls, in which case it should slow down if we
> | like conservation of energy. But in any case, whether there's
> | radiation present may be frame dependent.
> |
> | Does an electron falling toward the Earth radiate?
>
> I think it's called Cherenkov radiation, but you only get it in a
> medium.
No, Cherenkov radiation is what you get when a charged particle
travels faster than SoL in a medium. Has nothing to do with
acceleration (save that it's accompanied by rather rapid
deceleration).
The "falling charge" question is, I am assured, a fascinating problem
in general relativity but I don't happen to know the answer, nor do I
happen to feel fascinated by the question. But that's just me...
> A good example might be the Aurora Borealis... Look on the
> ground underneath the lights, you may find some dead muons as
> well. They are not easy to see, they are white and all that snow
> camouflages them. The electrons are easier to spot. They are blue
> with little minus signs painted on the side. Red balls might be
> snooker balls, return those to the billard table.
>
>
> | > I have a similar problem with sound, my ear trumpet only works
> | > if it has a wall of some kind but that funnels mosquitoes into
> | > my cochlea, which is why I said empty air.
> |
> | If you squash them after they get stuck in your cochlea, you
> | should eat them afterwards, just to be consistent.
>
> Oh, I do! I prefer to keep then out, though. The doctor said they
> contain "bad air", or mal-aria, and then he wants to stick needles
> in me.
>
> | > | The statement of this postulate seems ambiguous. Unlike
> | > | vacuum, air can have a state of motion, and this doesn't say
> | > | what happens if the air is in a state of motion relative to
> | > | the receiver.
> | >
> | > Vacuum can't move? Surely you jest!
> |
> | No, vacuum can't move.
>
> Who says so?
I did, just now. Einstein should have, but unfortunately he didn't.
It's there in the math, however, if you look hard enough.
All velocities in relativity theory are relative to some frame of
reference, and, at least in principle, they are relative to an
observer who occupies that frame of reference. None of them are
relative to "vacuum" per se, because vacuum has no particular velocity
of its own.
This is a confusing point, which is not well expressed in the 1905
paper (at least in English translation).
If you want to insist on talking about velocities relative to the
vacuum you're going to have to tell me how an observer determines his
own velocity relative to the vacuum. I claim you can't do that,
because there's no way you can "stick a pin" in the vacuum and watch
it to see how fast it's going.
> |
> | > As Sue says,
> |
> | Sue says whatever is needed to keep the argument going.
> |
> | > if the train comes to the station then the station comes to the
> | > train.
> |
> | Does the train stop at the station?
>
> Nope. It was an express.
If it doesn't stop then the relationship is indeed reciprocal but I
still take issue to the idea that the station can come "into" the
train. It won't fit.
> "Calling all stations, Chatham, Rochester, Strood, Higham.." thats a
> slow train to Charing Cross.
> The fast train to Victoria only stops at Chatham, Bromley South and
> Victoria.
> I can tell you've never travelled on a train.
I traveled to Paris on a train. That should count for something.
(But the announcers were speaking French and I didn't understand a
word of it ... not that I've every understood a train announcer
speaking English, either, for that matter.)
> | Then it must have decelerated.
> | Did the station decelerate, too? Nope, not as a rule.
>
> Aww... so there IS a universal absolute frame of reference after
> all?
I have no idea if there's an absolute frame. Relativity theory
doesn't _forbid_ an absolute frame, any more than it _forbids_ an
aether. It just doesn't _require_ either one.
> Maybe that's where the universal master clock is... I think
> Ernst Mach might shed some sound on it, do you?
> http://en.wikipedia.org/wiki/Image:Ernstmach.jpg
I never bought Mach's principle. Einstein found it useful, or so I've
read, but the notion that acceleration depends on the fixed stars
always sounded like abject nonsense to me.
Two weights and a string in an otherwise empty universe can spin
around each other, and if you cut the string (OK it's otherwise empty
except for you and the scissors) they'll fly apart. Stating that they
wouldn't, because there aren't any stars present, seems like a total
leap of faith with nothing at all to support it.
> | So, the situation isn't symmetric, and it's not really correct to
> | say the station "comes into the train".
>
> I guess we'd better let Galileo and Ernst battle that one out. Isaac
> and Albert should be in on it too. Isaac reckons there is something
> funny about stirring coffee, it rises to the sides of the mug no
> matter which way you stir the sugar in. You probably don't take
> sugar... or even coffee...
I make a quart of the stuff every morning.
Coffee, sugar, dark chocolate, and bourbon are all good vegan foods.
Coffee creamer (that fake stuff made from palm trees) is vegan too but
I don't use it myself.
> Maybe the entire universe is spinning
> around the mug's contents...
Mechanics breaks into little bitty pieces if you assume that, and it
doesn't even matter which kind of mechanics you're talking about.
> Albert has his magnet and conductor
> that seem to follow Galileo... Whatever, I'm out of my depth, this
> is too much empirical data for me. You are a follower of the Albert
> school of thought, are you not?
No, I have no shrine to Einstein, I'm not even on a first name basis
with him. I have to dig out one of his books every once in a while to
answer some post of yours, but I don't spend nearly as much time
following him as you do, I suspect... :-)
I enjoy the math.
I'm also getting a kick out of reading Stephen Hawking's "Une Brève
Histoire du Temps" which I picked up used for a couple bucks. It's a
very light read but it's fun. It's more of a history-of-science book
than a science book, which I suppose should have been apparent from
the title.
> | In any case "comes into" suggests containment, and while the train
> | may be contained in the station the reverse is never true.
> |
> | > Nothing ambiguous about it, the speed of empty space is a
> | > constant, c, in the inertial frame of reference of the light.
> |
> | Light has no inertial frame in relativity.
>
> Forgot about it, huh? Oversights can be forgiven.
It's a peculiarity of the math. It breaks if you try to describe an
inertial frame traveling at C relative to some other inertial frame.
In consequence, light doesn't get a FoR of its own.
> | In emission theory its velocity isn't fixed so the speed of "empty
> | space" wouldn't be fixed either.
>
> Well of course.
> In emission theory we adhere to the magnet and conductor Albert told
> us about and called the PoR. Ernst and Isaac's coffee spills over
> the side of the mug, which is why brandy snifters were invented. I
> think I'll side with Ernst and Isaac, I like brandy.
Never acquired the taste. Bourbon slides down better.
> I still like that magnet and conductor though... pity Albert denied
> it and called it a first order approximation... I can't help
> wondering whether we get cheaper electricity by spinning a magnet in
> a rotor with a conductor in the stator or the other way around. As
> you say, the situation isn't symmetric, and it's not really correct
> to say the magnet "comes into the conductor" or even "the conductor
> comes into the magnet." What the [train] conductor should say is
> "Fare please", or "FAIR, please", as they do on British Rail. Sue
> didn't say "into", you made that one up.
Oh crud, so I did. Mistake. I read it as "into" rather than "to".
Sorry; since it was "to", not "into", it actually made perfectly good
sense either way.
> Be 'fare' and pay up. You owe me one snifter of brandy, I've caught
> you cheating. You can try to win it back, but you'll have to be
> 'goddamn' sharp. I learnt that in Pittsburgh... "God bless goddamn
> America!"; Yonko, who said that, was a nice old guy. 76 years of
> age, still working and still putting his son through college at over
> 40 years of age. I could only shake my head and remain
> silent. Yonko had a stroke... I never saw him again. Shoulda been
> the useless son in his stead. Oh well, Yonko loved him, who am I to
> judge another? Makes me weep though, goddammit!
>
>
> | > I guess I should have told you about the dynamic reciprocal
> | > action of a conductor and a magnet. "The observable phenomenon
> | > here depends only on the relative motion of the conductor and
> | > the magnet, whereas the customary view draws a sharp distinction
> | > between the two cases in which either the one or the other of
> | > these bodies is in motion. " -Einstein. I think he borrowed it
> | > from Galileo.
> |
> | Constant linear motion is relative. Acceleration OTOH is absolute.
>
> That's Sue's "station comes to the train", not Steve's "station
> comes INTO the train can't happen." You owe me a brandy, and I
> think Sue deserves one too.
Can I email you one?
Sue'll have to buy her own, though.
> I'll agree d^2x/dt^2 is absolute. (For now). 't' better be absolute
> also.
No, we can't have "t" being absolute. Sagnac's experiment, repeated
with glass fibers in place of vacuum, shoots the pins right out from
under absolute time, even at low speeds.
> x can be anything it likes or you like. Isaac and Galileo
> will agree with me. Albert will not. Dunno about Ernst or you, but
> its 3:2 already. I'd prefer 4:1. Or did you want to bring in your
> pal, (what's his name? ) Orentz, or something? Laurence, that's it!
> Or is it Lawrence... I forget. Anyway, do that and I'll bring
> Johannes Kepler. Not Johannes Brahms, although he's a good musician.
I have no idea what you're talking about here.
> | > "Examples of this sort ... [yada yada yada] ... be called the
> | > ``Principle of Relativity''
> | >
> | > You wouldn't be taking the customary view and making a
> | > distinction, would you?
> |
> | No, I'm pointing out that in relativity theory, VACUUM has no
> | velocity. Only observers and observables move. There is nothing
> | about vacuum that can be observed so it's meaningless to talk
> | about its velocity.
>
>
> I'd almost agree with you, but that conductor and magnet still
> bother me, almost as much as "light is always propagated in empty
> space with a definite velocity c "... I can't help wondering what
> the speed (or velocity) of [light without a frame] is being compared
> to. It's pretty easy with the magnet moving INTO the conductor or
> the conductor moving INTO the magnet, because I think there is some
> kind of "aura" around the magnet, "lines of fours" I think it's
> called. And another one, called an electric field. Do electrics
> graze there like cattle in a meadow? How about an electric meadow?
>
>
> | FIELDS have no velocity, either. A magnetic or electric field
> | just "is".
> Oh, I agree. Whole-heartedly and with tongue in cheek. Radio doesn't
> work. Wanna bring in Maxwell and Hertz as well?
I didn't think you'd like that one too much. :-)
On the other hand I think we can assume there are no lurkers here
because I also didn't think anyone else would like it much, either.
The point is that in E&M as it's now taught, based on SR, the
"velocity" of the fields (E or B) is never used, and in fact is never
even defined. The fields "propagate" (splitting a hair) in the sense
that they appear in places the weren't previously, and disappear from
places they were, but they don't "move" in the sense that one might
mean if one said "A moving "B" field will affect a stationary
electron". It won't. An electron which appears stationary to me will
be unaffected by any B field I measure. It will, however, move in
response to an induced E field which I may measure if there happens to
be a magnet around which is also moving relative to me.
The force on a charged particle is
F = q(E + VxB)
(unless I've flipped the sign). Of course, q is the amount of charge,
V is the velocity of the charge, E and B are as usual,'x' is the cross
product. But the "velocity" of the _field_ is not present in the
formula.
To make this any more clear I'd need to start typing in tensors and
I'm not going to do that tonight.
(Oh, by the way, _magnets_ can move all they want...)
> | Its value at a particular point can change as time passes, but the
> | field doesn't "move". That includes the fields in "traveling
> | waves" such as light and radio: when you look at the equations to
> | see what's going on, there's nonzero dE/dt and nonzero dB/dt and
> | there's a velocity associated with the maxima and minima in the
> | fields, but the fields themselves aren't described as "moving".
>
> Fixed in the absolute frame of reference called vacuum, huh? I think
> Ernst will agree with you, and Isaac wants an absolute time. Maybe
> there IS a difference between the motion of a magnet past a
> conductor and the motion of a conductor past a magnet... Hmmm? Tell
> ya what!! Let's see what happens when we accelerate one past the
> other and the other past one. I happen to think the magnet takes its
> field along for the ride, but what do I know? Only way to find out
> is experiment, I could be wrong.
:-)
Accelerating magnets and conductors are a mess to solve for. To do it
right you need to use the retarded integrals of the charge densities
over space.
> | Energy moves, and the Pointing vector says where it's going when
> | it's the energy of the E and B fields. Momentum moves. But the
> | fields themselves don't "move".
>
> Ok. Magnets don't move, if you say so.
No, I didn't say that. Magnets can move. It's just that the field
... um ... propagates or evovles, it doesn't "move".
OK, I'm splitting hairs. The only real point to this is that "motion"
of the field isn't actually used to determine the effect on anything;
it's only "motion" of the charges that really matters. And perhaps
more important, in some cases "motion" of the field is not even well
defined.
Consider a very large fixed magnet with very large pole pieces -- so
large that the field is perfectly uniform on the pole pieces. Now,
from the point of view of a tiny observer standing near one of the
pole pieces, is the field moving or at rest? Remember, the field is
perfectly uniform, so whether it's moving or not you won't detect any
change in it. How do you measure its motion?
If you say "An electron will accelerate uniformly if the field is
moving" then I'll ask you how you tell the difference between the
"moving" uniform magnetic field and a "stationary" uniform magnetic
field superposed on a "stationary" uniform electric field. Of course,
the answer is that you can't. So, one can argue (in fact, I just did
argue) that the B field can't really be considered to be "moving" in
that case.
> I must have moved my fridge
> to the magnet. I hope you notice I'm not arguing with you. I'm
> hanging on your every word. It was my fridge that accelerated and
> decelerated, but the station doesn't come into the train and the
> fridge doesn't go into the magnet.
>
>
> |
> | An electron, stationary in a particular FoR, does _not_ react to
> | any B field as measured in that FoR, because the B fields don't
> | "move" relative to the electron.
>
>
> Quite so. The fridge comes to the magnet and the train comes into
> the station. I fully understand.
No, I'm not sure I got the point across.
A moving magnet causes an electric field in its vicinity, and that's
what a "stationary" electron reacts to. In classical E&M it doesn't
react to the B field because it isn't moving.
For what it's worth Einstein hated this approach to E&M, or so I have
read, somewhere. The asymmetry of treating the moving electron and
the moving B field so differently really bugged him.
> | However, electrons _are_ observed to respond to B fields when the
> | electrons are moving relative to an observer in a frame of
> | reference in which there is a nonzero B field.
>
>
> Weelllllll... have you consider that electrons don't have frames of
> reference? Light doesn't, so maybe they don't either.
Sure they do, and they have little eyes which they use to determine
what direction they're going in, and they're all staring at YOU, RIGHT
NOW!
Oops, sorry, got carried away there...
Yes, there is a perfectly good FoR associated with each electron
because they always travel slower than C. The trouble with light is
that it goes at C (duh) and you run into a zerodivide error trying to
compute the transform into its frame of reference. So a photon has no
Lorentz frame, and has no 4-velocity, either. Not _zero_ 4-velocity
-- rather, _no_ 4-velocity: it's undefined.
> "Without affecting the general character of our considerations, we
> may and will assume that the electron, at the moment when we give it
> our attention, is at the origin of the co-ordinates, and moves with
> the velocity v along the axis of X of the system K. It is then clear
> that at the given moment (t=0) the electron is at rest relatively to
> a system of co-ordinates which is in parallel motion with velocity v
> along the axis of X."
>
> Excerpt from "Dynamics of the Slowly Accelerated Electron" by Albert
> Einstein.
>
> Looks like you are right... the conductor moves and the magnet
> doesn't. I'll make sure I use slip rings on the rotor and a
> magnetic stator next time I design a generator.
Huh? Of course the conductor moves, otherwise how's he ever get to
all the passengers to take their tickets?
> | There is a lot of confusion on this point, even in reasonably
> | reputable textbooks.
>
>
> Oh, I'm sure there is. Even I'm confused, I could have sworn my
> bicycle used a moving magnet to power the lights. Maybe the bike
> goes around the wheels, huh?
No, acceleration is absolute.
I shouldn't have mentioned that bit about the fields... it detracts
from the overall clarity of the argument, I think.
> | Air, on the other hand, has properties that allow one to sensibly
> | talk about its motion.
>
> Of course. The plane flies INTO the air, the kitchen window blows
> INTO the wind. Air has no motion. See how agreeable I am?
If you wave a kitchen window in the wind, you will cause turbulence in
the air. Vortices, you know.
You can't have vortices in the vacuum, or so most people believe.
QED.
> | > But you are correct, the postulate doesn't say what happens if
> | > the air is in a state of motion relative to the
> | > receiver. Einstein's postulate doesn't say what happens if the
> | > vacuum is in a state of motion relative to the receiver either,
> |
> | As I said, vacuum can't "move". Air can.
>
>
> Ah, but it doesn't. It COULD, but the plane flies INTO the air, like
> the train comes INTO the station. The air doesn't come to the plane
> (of course).
No, it comes _into_ the plane, through the air intakes, where it's
compressed and forced into the cabin, where it dries out everybody's
membranes.
> The plane accelerated and so did the house when it only
> seemed the wind was blowing through the kitchen window.
>
>
> | > so no harm, no foul. What is the speed of light relative to? The
> | > empty space.
> |
> | Nope, it's relative to an observer.
>
>
> That's not what Albert said. He didn't mention any observer in his
> second postulate. Maybe you have some other theory that isn't
> Albert's. Has it been published? I'd like to read it. I can't
> discuss some other theory until I've read it, sorry.
Einstein's 1905 paper was very original, and packed choc full of
information and ideas, but it's not a stunning masterpiece of
clarity.
Just how do you think the vacuum measures the velocity of the light
passing by?
And again, how does an observer measure the velocity of empty space,
if he's trying to figure out how fast light is going relative to it?
> | After it's emitted, the emitter can (in principle) measure its
> | velocity, too, and hence "observe" it, so the emitter also
> | qualifies as an "observer". Vacuum can't observe anything, and
> | has no properties that let you assign a velocity to it, so we
> | can't talk about the velocity of the light relative to the vacuum.
>
>
> We can't? Albert said it was c in empty space. I'm confused.
Possibly.
> Maybe
> you have some other theory I haven't read. I'm discussing "On the
> Electrodynamics of Moving Bodies", by Albert Enstein, not "Harry
> Potter and the Sorcerer's Stone" by Joanna Rowling. Both are great
> fiction, but I'm not sure which you are referring to. Maybe I missed
> a passage in Joanna's book.... I didn't in Albert's.
I don't spend a lot of time looking at the Electro paper (every few
months, when I get into an argument with you, is about it). I'm
talking about relativity theory as it exists, but I know you'd rather
discuss Einstein's exact words as they were written in 1905.
Fundamentalism doesn't generally appeal to me, but there you are, when
you're arguing with a fundamentalist you'd better concern yourself
with the exact words or you're just going to go in circles, right?
So, regarding his exact words, if you want to understand a scientific
paper (rather than just try to pick nits out of it) you need to look
for an interpretation that makes sense. If you look for an
interpretation that _doesn't_ make sense, you can almost always find
one; but if you want to know what the author meant, you're usually
better off looking for an interpretation that _does_ make sense than
one that _doesn't_.
In this case, the interpretation that says the light moves at some
velocity relative to the velocity of the vacuum is one that doesn't
make sense.
If it makes sense to you, please tell me how you measure the velocity
of the vacuum ... because without that, you can't tell how fast
anything is going "relative" to it. And I don't know any way to
determine how fast "empty space" is moving.
I did? I thought I said the opposite. It's independent of the
observer, they all measure it as "C". All at once. That's the
point.
> and he's got all of Albert's math.
No, I don't. Einstein had a much, much stronger grasp of the math
than I ever will, but you'd need to get into his later papers to
really see it.
Try reading his 1916 GR papers, "Foundations" and "Hamilton's
Principle".
> Isaac would
> be curious, then rewrite it so that it made objective sense. Both
> would love to see V1493 Aql explained, though, and Albert can't
> offer anything. Androcles can, he has a computer. William of Ockham
> would dismiss Albert in the blink of an eye.
>
>
> | > I don't know what happens when a
> | > conductor passes a magnet at speed c,
> |
> | It melts.
>
> Generators can get quite warm, that's for sure.
>
> I though an electron beam in a monitor tube was a current that was
> deflected by a magnetic field as they moved past it. Electrons melt?
Only when they travel at C.
> I didn't know that. Still, I guess you know. Maybe the electrons
> melt the vacuum, huh? Or do they turn through 90 degrees and head
> off toward the pole of the magnet? Nah... too much inertia... They
> must melt.
>
>
> | > perhaps we adopt the customary view.
> | >
> | >
> | > |
> | > | If we assume it's supposed to mean the velocity is independent
> | > | of the state of motion of the emitter _or_ the air relative to
> | > | the receiver then we've got an analogy to relativity.
> | >
> | > Assume? Can't do that, sorry.
> |
> | How about "guess"?
>
>
> Not science, old chap.
Reading other folks' writing on science often involves "assuming" or
"guessing" what they meant. If the rest of what they wrote makes
sense with that "assumption" or "guess" then one can conclude that one
probably got it right.
If they're still alive you can ask them.
Cripes, where have you been for the last few decades? Air's been
moving all over the place lately.
Ever hear of a "jet stream"? That's what it uses when it's really in
a hurry.
> and if it moved it would
> disappear down a Chinese coal mine and come back up through a
> Pennsylvania coal mine (or the other way round). The plane flies
> INTO the air, so does the kitchen window if you leave it open.
>
>
>
> | How do you build an anemometer that shows how fast vacuum is
> | going?
>
>
> Dunno... I'll have to think about it.
Do that. If you can't build one, even in principle, then you can't
talk sensibly about how fast the vacuum is moving, and without that,
you can't talk about how fast something is moving relative to the
vacuum.
> I agreed with you and not
> with Albert. Vacuum can't move. How do you measure the speed of
> light in a vacuum to test Albert's second postulate?
You need a big blobby pulse consisting of many photons, so one
observer can use up some of the photons and still leave some for the
next observer, and you need at least two observers who are stationary
relative to each other, and they must have clocks which are in sync,
and you know the rest of the drill.
If you want to economize on observers you can use just one along with
a mirror, but you need to be sure the mirror's stopped relative to the
single observer.
> You'll have to
> make sure the vacuum isn't moving, right? If it moved it might
> carry the light along with it, like a river carries a boat
> downstream.
No, there's no drag associated with moving vacuum, in part because it
doesn't move.
> Sue reckons the vacuum has the properties of
> permittivity and permeability, she loves to talk about those. Keeps
> talking about alpha and mu0... I don't think they exist. mu1, maybe.
So maybe Sue can tell you how to measure the velocity of the vacuum.
I sure can't, as far as I know it can't be done.
Thank you, I shall add it to my list of papers-to-be-read-someday,
if-I-live-so-long.
Right, but which angle is it?
Einstein made a rather surprising choice for the angle he would use in
that formula, if I recall correctly, but I don't recall off hand which
angle he used. Do _you_ know which angle it was?
> | Angle between the emitted ray, or the received ray, and ... what?
> | There's more than one way to set it up and the answers are
> | different depending on how you do it.
>
>
> Yep. I tried to tell Albert that very same thing. In the end I had
> to figure out what he meant. He didn't put cos(phi) in beta = 1/
> sqrt(1 - [v.cos(phi)/c]^2) either. Maybe he overlooked it.
>
>
>
> | > | > AND I've got
> | > | > Mach1 = (Mach1 +v)/(1 + v/Mach1).
> | > | >
> | > | >
> | > | > Now they know that the speed of sound is measured to be
> | > | > Mach1 in all frames of reference. I said so.
> | > | >
> | > | >
> | > | > | >
> | > | > | > "Now we must bear carefully in mind that a mathematical
> | > | > | > description of this kind has no physical meaning unless
> | > | > | > we are quite clear as to what we understand by 'time'. "
> | > | > | > -- Albert Einstein.
> | > | > |
> | > | > | Obviously.
> |
> | > | >
> | > | > Well then, I defined time, didn't I? You did understand it,
> | > | > I trust?
> | > |
> | > | Sorry, I think I missed that. Could you repeat the
> | > | definition, please?
> | > Sure. The ``time'' required by SOUND to travel from A to B
> | > equals the ``time'' it requires to travel from B to A.
[ snip dupes ]
> | Sorry, that doesn't define "time", it just tells me how it behaves
> | in one very specific case.
>
>
> You'd better tell Albert, then. He uses that stuff you call "light"
> to replace my "sound".
Yeah, he didn't do a very explicit job of defining "time" in that
paper. I think he directed the paper mostly at people who already
knew that "time" was a coordinate in the model, and it was what clocks
measure in the real world, and that testing the model would consist of
comparing clock readings to predicted coordinate values and seeing if
they lined up.
> Personally I think it is rather daft, but
> you can't have time dilation without it. Remember that horrible
> equation we discussed?
> ½[tau(0,0,0,t)+tau(0,0,0,t+x'/(c-v)+x'/(c+v))] =
> tau(x',0,0,t+x'/(c-v)) ?
No, I've blocked it out.
> That '½' is there to compute the time it takes for light to go from
> A to B. The round trip from A to B and back again cut in half. I'm
> using sound instead. I cribbed from Albert. Naughty of me.
>
>
> | [ snip ]
> |
> | > | > Concorde never once exceeded Mach1,
> | > |
> | > | Really? So it was all a hoax, after all?
> | >
> | >
> | > Of course. Mach1 = (Mach1 +w)/(1+w/Mach1) If you have two
> | > Concordes crossing the Atlantic and going in opposite directions
> | > their closing speed is given by V = (v+w)/(1+vw/Mach1),
> |
> | What are they doing, playing "chicken"?
> |
> | OK, I've got a question for you.
> |
> | How do you handle the Sagnac effect in emission theory?
>
>
> Emission theory is only about light in EMPTY space.
I thought you'd said previously that in a physical medium such as air
or glass, light travels at SoL in the air or glass, relative to that
object. At least, that's what you said when we were arguing about
redshifts and spectroscopes, a long time back. Are you disavowing
that now?
It doesn't help, anyway. The Sagnac effect works just fine using
_evacuated_ tubes, too. (You know, tubes filled with empty space,
which you just said emission theory _is_ about.)
> Sagnac space isn't empty.
The experiment's been done both ways: empty space and non-empty
space. The result is much the same: the time to go around the ring
is different one way than the other way, when the ring is rotating.
It's quite strange.
> My new "sound" theory with built-in time
> dilation isn't emission theory either. Looks like you snipped it,
> though.
Sorry; I thought we were done with it, and the wrapping had gotten
totally mangled on that section. Anyhow, it's just SR with mach1 in
place of C, right?
> What you need is the older "medium" theory. Sue is much more
> familiar with mus and alphas and permeabilities and such. Sorry to
> pass the buck, but light in a medium isn't my specialty. It has the
> speed of c/n relative to the medium, 'n' being the refractive
> index. It isn't source dependent anymore once it leaves the vacuum.
>
>
> |
> | Do you deny it exists (as Henri seems to do when pressed), or do
> | you have an explanation for it?
> |
> | Just curious.
>
>
> Good grief no. I NEVER deny empirical data. I deny impossible
> theories with badly thought out mathematics. I've tried to tell you
> about the errors before, but you quickly lose interest and snip what
> doesn't agree with your stomach. Androcles.
--
Autymn D. C.
> Yes, there is a perfectly good FoR associated with each electron
> because they always travel slower than C. The trouble with light is
> that it goes at C (duh) and you run into a zerodivide error trying to
> compute the transform into its frame of reference. So a photon has no
> Lorentz frame, and has no 4-velocity, either. Not _zero_ 4-velocity
> -- rather, _no_ 4-velocity: it's undefined.
I disproved the electron's case:
http://groups-beta.google.com/group/sci.physics.relativity/browse_frm/thread/8dbb9083a69f0ce6/8f3eb5ebae4ec4a3?lnk=st&q=%22short+and+sweet+proof%22&rnum=6#8f3eb5ebae4ec4a3
.
> In this case, the interpretation that says the light moves at some
> velocity relative to the velocity of the vacuum is one that doesn't
> make sense.
>
> If it makes sense to you, please tell me how you measure the velocity
> of the vacuum ... because without that, you can't tell how fast
> anything is going "relative" to it. And I don't know any way to
> determine how fast "empty space" is moving.
Androcles
| On Tue, 26 Jul 2005 02:31:38 +0000, Androcles wrote:
|
| >
| > "sal" <pragm...@nospam.org> wrote in message
| > news:pan.2005.07.25....@nospam.org...
| > | 650 lines ... some snipping is needed here.
| >
| > Ok, I'll snip what I've read and answered. I won't snip anything I
| > didn't answer.
| >
| > | On Sat, 23 Jul 2005 15:02:48 +0000, Androcles wrote:
| > |
| > |
| > | > Now did I say chicken eggs? Bright green flying elephant's
| > | > eggs, my friend.
| > |
| > | What? You can grow a whole chicken from an elephant egg??
| >
| > Nope. You can grow a whole bright green flying elephant from a
| > bright green flying elephant's egg, though. You need a black hole or
| > wormhole in spacetime to incubate them in, but there are plenty of
| > those around. I saw a black hole being discussed not too long ago,
| > on this very newsgroup. You know what FIFO is? Some peope mistake
| > it it for 'first in, first out', but that's garbage. It's actually
| > 'fiction in, fiction out'.
|
| On this side of the Atlantic we use GIGO for the latter: Garbage in,
| garbage out. FIFO is reserved for a queue.
I said it was garbage.
People don't queue on your side of the Atlantic, they "stand in line".
Here if you see a sign that says "Queues likely" it means the M25 London
Orbital is being used as a car park, or "parking lot".
|
|
| > | [ snip stuff (and more stuff) ]
| >
| > | > Einstein didn't say vacuum, he said "empty space" according to
| > | > http://www.fourmilab.ch/etexts/einstein/specrel/www/. Maybe
| > | > something was lost in the translation.
| > |
| > | That was a hundred years ago. We've advanced since then. Now we
| > | have a name for "empty space": we call it "vacuum".
| >
| > Ah.... That must be like McCullough the relativist. He says a
| > closing velocity is different to a relative velocity.
|
| This is semantic logic-chopping, really. Relative velocity, closing
| velocity -- either one works for me. Either way, it's the time
| derivative of a length, rather than the time derivative of the
| location of an object, and as such it's not a "velocity" at all in the
| sense that it doesn't tell you how fast something's going.
Can't agree. It isn't possible to state how fast anything is going
without a reference (usually implied) as to what that speed is
relative too.
|
| If two cars collide head-on, each going 60 MPH (which is legal again
| in this country), then as viewed by an observer by the side of the
| road each car had speed = 60 MPH (and velocity = +/- 60 depending on
| the direction, if we use the convention that speed = abs(velocity)).
| The "closing speed" or "relative speed" or whatever you want to call
| it is 120 MPH, but it's not the velocity of any object, as viewed by
| our roadside observer, because it's not the derivative of a position.
You display the same confusion that put Galileo under house arrest.
Why do people think the Earth is the absolute frame of reference against
which this 60 MPH is to be measured? The car is travelling around the
Sun,
a distance of approximately 93,000,000 * 2*pi miles, in one year.
In the frame of the fixed stars your 60 mph is a relative speed.
The Earth moves. ALL speeds are relative. No exceptions.
You've adopted what Einstein called the "customary view".
His magnet and conductor are hurtling around the solar system too,
at 0.0001c in the "empty space". That should make it quite possible
to detect relativistic effects easily, if there were any. Radio
transmission
to spacecraft near Saturn, relative to the spacecraft, are sent at
between
0.9999c and 1.0001c in empty space. In progress, right now.
The magnet takes its field with it.
"For if the magnet is in motion and the conductor at rest", says
Einstein.
It never happens. There is no state of "rest". Rest is simply a zero
speed
relative to whatever it is resting with.
| The time derivative of the X coordinate of car A is (let's say) +60
| MPH, and the time derivative of the X coordinate of car B is -60 MPH.
| Those are both velocities. But the time derivative of the _difference_
| between their X coordinates is -120 MPH, and as I already said it's
| not what we usually mean by a "velocity".
One car is considered to be "at rest", the other has a velocity of -120
mph
in the frame of reference of the first car. And that IS what *I* and
Newton
and Galileo and even poor confused Einstein (who wants to make a special
case for light in an absolute frame of reference he calls "empty
space"),
mean by velocity. The moment you say "time derivative" you are
unconsciously adopting Newton's absolute time, just as you unconsiously
adopted the Earth as a frame of reference for your X-coordinate.
I know what you mean because I'm used to dealing with everyday jargon,
but there is no absolute frame of reference.
|
| I think one of us here may be an Einstein fetishist but it's not me.
| (How much time have _you_ spent studying his words? More time than
| me, I suspect very strongly!) I also happen to think his language in
| the electrodynamics paper was not exactly crystal clear.
Yes, I've studied it in depth, the forensic criminologist takes the
scene
of the crime apart down to the minutest trace of DNA. Now I'm ready
to go to trial, accusing Einstein of deliberate fraud. Proving the case
is difficult with a prejudiced jury.
The deliberate lack of clarity with the repetitive "it is clear" is part
of my case against Einstein the huckster.
I acknowledge his intelligence, I will object to a plea of insanity.
Do you refer to forensic scientists as DNA fetishists?
I expect you to be a juror, but I know that you are not impartial.
Science was bombed on June 30th, 1905 by a terrorist.
It cannot be rebuilt until the accomplices have been rooted out.
|
| > c-v is a
| > closing velocity, (c+w)/(1+ w/c) is a relative velocity.
|
| If you want to define it that way go ahead but it sounds like a really
| confusing use of the language to me.
Not I. That was McCullough's obfuscation. He chose to appear
as a witness for the defence and mince in some words to explain
why Einstein was using the Galilean c-v, c+v velocities to derive
what Einstein calls the "Lorentz" transformation. c-v and c+v
are adequate to a mathematician. What name you give it isn't
important. I call it deliberate confusion.
I consider you to be a man of conscience, you can either be a
fair and impartial juror or stand accused as a co-conspirator.
You have to live with yourself. The hardest part has been getting
you to listen to the evidence, but progress has been made. We agree
that Einstein is not as clear as he professes.
|
| > Einstein
| > called c-v a relative velocity, but that was 100 years ago. What did
| > he know, huh? Maybe it's the 'w' instead of the 'v'... You can't
| > derive the Lorentz Transforms without a closing velocity.
| > "But the ray moves relatively to the initial point of k,
| > when measured in the stationary system, with the velocity c-v..."
| > -Einstein.
| > What did he know, huh?
| > Should'a said "But the ray moves CLOSINGLY to the initial point of
| > k, when measured in the stationary system, with the velocity
| > c-v...", right? I dunno why it isn't an opening velocity, the light
| > is running away from the initial point of k at c-v, but maybe we'll
| > change it in 100 years.
|
| I like the term "opening velocity". I've even used it in some post or
| other.
|
| Either way it's just a nit in his language which doesn't have much of
| anything to do with the actual meaning of the quantity in question,
| which is a time derivative of the difference between two space
| coordinates.
I agree wholeheartedly.
The term (c+v), in parentheses, is a single velocity in the k' frame.
The k' frame is the name I give to the hidden frame that Einstein
wants not to be remembered, hence it isn't named. He has to refer to it
so he calls it a system of coordinates x',y,z independent of time.
The three "frames" are
K, a system of coordinates x,y,z using t.
k', a system of coordinates x', y', z' using t (Newtonian time)
k, a system of coordinates xi, eta, zeta, using tau.
Two functions are needed to transform between K and k.
g(x) = x-vt,
written as x' = x-vt,
and
f(x) = x/sqrt(1-v^2/c^2)
f(g(x)) = (x-vt)/sqrt(1-v^2/c^2)
written as xi = (x-vt)/sqrt(1-v^2/c^2)
|
| > | Anyway, his space wasn't really empty, because he had light rays
| > | passing through it.
| >
| >
| > True, true.
| > My air isn't really empty either, it has sonic beams passing through
| > it.
|
| And according to relativity theory sonic beams have mass, since they
| carry energy....
Well certainly!
|
|
| > | > Anyway, vacuum doesn't really convey the concept of agoraphobia,
| > | > it reminds one of an enclosure of some kind. Run an electron
| > | > down a long steel tunnel that is full of vacuum and as Sue says,
| > |
| > | AFAICT Sue says whatever is needed to keep the argument going.
| > | She/he seems to enjoy arguing, regardless of what side she/he is
| > | on. You're a little easier to argue with than Sue: I always know
| > | which side you're going to come down on.
| >
| > Ah, but I don't give up.
|
| So why did you take your website down, anyway?
Health and wealth go together well. Lose one, you often lose the other.
| > I pay attention and reply. I never know
| > when you are going to ignore a point I make and pretend it isn't
| > there.
|
| When I get bored, and run short on time.
| Hard to tell from the outside when that point is, of course (you're
| dealing with a "black box" model, in some sense).
Nothing more boring than being in bed all the time.
Thank goodness for free libraries.
I had plenty of time, but no energy to use it.
Y'know, Einstein was a clerk in a Swiss patent office.
What would a Swiss gentleman want a patent for?
Well, what do they make in Switzerland?
Cuckoo clocks.
Little wonder the cuckoo Einstein was fascinated by time. :-)
|
| > | > the coulomb coupling with charges in the wall of the tube will
| > | > slow the electron's speed.
| > |
| > | I don't know about coulomb coupling, but it might induce some eddy
| > | currents in the walls, in which case it should slow down if we
| > | like conservation of energy. But in any case, whether there's
| > | radiation present may be frame dependent.
| > |
| > | Does an electron falling toward the Earth radiate?
| >
| > I think it's called Cherenkov radiation, but you only get it in a
| > medium.
|
| No, Cherenkov radiation is what you get when a charged particle
| travels faster than SoL in a medium. Has nothing to do with
| acceleration (save that it's accompanied by rather rapid
| deceleration).
No, No, NO!
Cherenkov radiation is what you get when a charged particle
travels faster than SoL in a medium.
Do you always agree by saying "No"? It must drive your wife
crazy. Perhaps she's used to it...
| The "falling charge" question is, I am assured, a fascinating problem
| in general relativity but I don't happen to know the answer, nor do I
| happen to feel fascinated by the question. But that's just me...
Ah well... see, a physicist is interested in the issue, a failed
mathematician and huckster wouldn't necessarily care.
You brought it up, I answered, now you aren't interested...<shrug>
[snip aurora, sal is not interested]
| > | > Vacuum can't move? Surely you jest!
| > |
| > | No, vacuum can't move.
| >
| > Who says so?
|
| I did, just now. Einstein should have, but unfortunately he didn't.
| It's there in the math, however, if you look hard enough.
I did, math is based on postulates.
"light is always propagated in empty space with a definite velocity c"
follows AFTER "Principle of Relativity", the predominant postulate.
Hence the speed of light, c, is relative to the empty space, not the
observer who isn't mentioned, nor the source, specifically stated.
What else is there?
The vacuum moves, relatively to the light, by the PoR postulate.
The air moves relatively to the sound as well.
There's more to math than algebra, y'know. Proof based on axioms
is what its about, and mathematicians are pedantic.
|
| All velocities in relativity theory are relative to some frame of
| reference, and, at least in principle, they are relative to an
| observer who occupies that frame of reference.
Of course, but relativity theory doesn't have sole ownership of
the principle of relativity.
None of them are
| relative to "vacuum" per se, because vacuum has no particular velocity
| of its own.
That's a contradiction of Einstein's first and second postulates
"All velocities in relativity theory are relative to some frame of
reference" -- sal
and the frame of reference for the speed of light, c, is the vacuum.
|
| This is a confusing point, which is not well expressed in the 1905
| paper (at least in English translation).
|
| If you want to insist on talking about velocities relative to the
| vacuum you're going to have to tell me how an observer determines his
| own velocity relative to the vacuum. I claim you can't do that,
| because there's no way you can "stick a pin" in the vacuum and watch
| it to see how fast it's going.
Me? I wouldn't have a clue how to thumbtack a vacuum.
I'm only quoting Einstein, as written, I'm not insisting.
I'm putting Einstein on trial here, HE said it. If it doesn't make
sense to you then I've made my point.
| > | Does the train stop at the station?
| >
| > Nope. It was an express.
|
| If it doesn't stop then the relationship is indeed reciprocal but I
| still take issue to the idea that the station can come "into" the
| train. It won't fit.
Of course it won't, but a vacuum will fit inside a TV tube quite
easily, and these days there are TVs on aircraft.
That proves the vacuum moves relatively to the ground and is at
rest relatively to the plane. There's the "pin" you wanted.
| > "Calling all stations, Chatham, Rochester, Strood, Higham.." thats a
| > slow train to Charing Cross.
| > The fast train to Victoria only stops at Chatham, Bromley South and
| > Victoria.
| > I can tell you've never travelled on a train.
|
| I traveled to Paris on a train. That should count for something.
| (But the announcers were speaking French and I didn't understand a
| word of it ... not that I've every understood a train announcer
| speaking English, either, for that matter.)
British Rail went over to tape recordings a long time ago, but today
it's been upgraded to computerized announcements and is much clearer.
"Calling all sta...Calling all Calling all Calling all Calling all all
all all all all..."
You can plainly hear every syllable.
AND it says "PLEASE mind the doors" as they crush you between them.
Ah, the joys of polite automation...
"This is your captain speaking...USAir apologises for the delay in
take-off but the machine that usually breaks the handles off your
luggage is broken and our staff are breaking them off by hand for you."
|
| > | Then it must have decelerated.
| > | Did the station decelerate, too? Nope, not as a rule.
| >
| > Aww... so there IS a universal absolute frame of reference after
| > all?
|
| I have no idea if there's an absolute frame. Relativity theory
| doesn't _forbid_ an absolute frame, any more than it _forbids_ an
| aether. It just doesn't _require_ either one.
|
If the vacuum doesn't move, it must be at rest. What do you imagine
a vacuum cleaner collects? If it was dust, I'd be a dust cleaner.
|
| > Maybe that's where the universal master clock is... I think
| > Ernst Mach might shed some sound on it, do you?
| > http://en.wikipedia.org/wiki/Image:Ernstmach.jpg
|
| I never bought Mach's principle. Einstein found it useful, or so I've
| read, but the notion that acceleration depends on the fixed stars
| always sounded like abject nonsense to me.
Wasn't it you that said acceleration was absolute?
I forget, I get confused about who said what. I'm getting old.
|
| Two weights and a string in an otherwise empty universe can spin
| around each other, and if you cut the string (OK it's otherwise empty
| except for you and the scissors) they'll fly apart. Stating that they
| wouldn't, because there aren't any stars present, seems like a total
| leap of faith with nothing at all to support it.
Yes, well, I consider a lot of relativity is a leap of faith.
Especially that one about the speed of light being the same in all
frames of reference, with time dilation thrown in for good measure.
|
|
| > | So, the situation isn't symmetric, and it's not really correct to
| > | say the station "comes into the train".
| >
| > I guess we'd better let Galileo and Ernst battle that one out. Isaac
| > and Albert should be in on it too. Isaac reckons there is something
| > funny about stirring coffee, it rises to the sides of the mug no
| > matter which way you stir the sugar in. You probably don't take
| > sugar... or even coffee...
|
| I make a quart of the stuff every morning.
|
| Coffee, sugar, dark chocolate, and bourbon are all good vegan foods.
|
| Coffee creamer (that fake stuff made from palm trees) is vegan too but
| I don't use it myself.
You mean the powdered white paint? Me neither. Nor those pink sachets
with the list of chemicals on them. Pink paper doesn't dissolve in coffee
very well, the coffee gets cold before you can stir it in.
|
|
| > Maybe the entire universe is spinning
| > around the mug's contents...
|
| Mechanics breaks into little bitty pieces if you assume that, and it
| doesn't even matter which kind of mechanics you're talking about.
I know a mechanic who fixes breakdowns.
|
| > Albert has his magnet and conductor
| > that seem to follow Galileo... Whatever, I'm out of my depth, this
| > is too much empirical data for me. You are a follower of the Albert
| > school of thought, are you not?
|
| No, I have no shrine to Einstein, I'm not even on a first name basis
| with him. I have to dig out one of his books every once in a while to
| answer some post of yours, but I don't spend nearly as much time
| following him as you do, I suspect... :-)
|
What was all that stuff you wrote about on Sagnac, then?
It's not even a moving vacuum fibre...
| I enjoy the math.
Do you? Cool! What is the fewest number of colours needed for
a map, no two countries with the same colour to share a border,
all countries to share a border with another,
1) on a plane sheet of paper, (4 colours)
2) on a Mobius strip,
3) on a Klein bottle,
4) on a sphere ?
Assume the surface is transparent, same colour shows through
the other side.
|
| I'm also getting a kick out of reading Stephen Hawking's "Une Brève
| Histoire du Temps" which I picked up used for a couple bucks. It's a
| very light read but it's fun. It's more of a history-of-science book
| than a science book, which I suppose should have been apparent from
| the title.
|
Yeah... I read the English translation many years ago.
Hawking's haughty first wife didn't like me much, she thought
he shouldn't have a beer. Can't think why she brought him into a bar...
|
| > | In any case "comes into" suggests containment, and while the train
| > | may be contained in the station the reverse is never true.
| > |
| > | > Nothing ambiguous about it, the speed of empty space is a
| > | > constant, c, in the inertial frame of reference of the light.
| > |
| > | Light has no inertial frame in relativity.
| >
| > Forgot about it, huh? Oversights can be forgiven.
|
| It's a peculiarity of the math. It breaks if you try to describe an
| inertial frame traveling at C relative to some other inertial frame.
| In consequence, light doesn't get a FoR of its own.
Ah... I see. The butler didn't do it, so there was no murder.
|
|
| > | In emission theory its velocity isn't fixed so the speed of "empty
| > | space" wouldn't be fixed either.
| >
| > Well of course.
| > In emission theory we adhere to the magnet and conductor Albert told
| > us about and called the PoR. Ernst and Isaac's coffee spills over
| > the side of the mug, which is why brandy snifters were invented. I
| > think I'll side with Ernst and Isaac, I like brandy.
|
| Never acquired the taste. Bourbon slides down better.
I'd have to have Coca Cola with bourbon. Brandy I like gently heated.
The Germans like warm wine, too.
|
|
| > I still like that magnet and conductor though... pity Albert denied
| > it and called it a first order approximation... I can't help
| > wondering whether we get cheaper electricity by spinning a magnet in
| > a rotor with a conductor in the stator or the other way around. As
| > you say, the situation isn't symmetric, and it's not really correct
| > to say the magnet "comes into the conductor" or even "the conductor
| > comes into the magnet." What the [train] conductor should say is
| > "Fare please", or "FAIR, please", as they do on British Rail. Sue
| > didn't say "into", you made that one up.
|
| Oh crud, so I did. Mistake. I read it as "into" rather than "to".
| Sorry; since it was "to", not "into", it actually made perfectly good
| sense either way.
You read 1/sqrt(1-v^2/c^2) as less than 1, as well. Mistake.
That 'c' is into the BIG vacuum that doesn't move, not the little vacuum
that does, into the TV into the plane into the air. Pretty soon we'll have
TV tubes into the ISS with a moving vacuum inside the stationary vacuum,
just a wall of glass separating them.
|
|
| > Be 'fare' and pay up. You owe me one snifter of brandy, I've caught
| > you cheating. You can try to win it back, but you'll have to be
| > 'goddamn' sharp. I learnt that in Pittsburgh... "God bless goddamn
| > America!"; Yonko, who said that, was a nice old guy. 76 years of
| > age, still working and still putting his son through college at over
| > 40 years of age. I could only shake my head and remain
| > silent. Yonko had a stroke... I never saw him again. Shoulda been
| > the useless son in his stead. Oh well, Yonko loved him, who am I to
| > judge another? Makes me weep though, goddammit!
| >
| >
| > | > I guess I should have told you about the dynamic reciprocal
| > | > action of a conductor and a magnet. "The observable phenomenon
| > | > here depends only on the relative motion of the conductor and
| > | > the magnet, whereas the customary view draws a sharp distinction
| > | > between the two cases in which either the one or the other of
| > | > these bodies is in motion. " -Einstein. I think he borrowed it
| > | > from Galileo.
| > |
| > | Constant linear motion is relative. Acceleration OTOH is
absolute.
Ah, that's why I couldn't find it. It was ahead of me today and
behind me yesterday.
The notion that acceleration depends on the fixed stars
always sounded like abject nonsense to me.
| > That's Sue's "station comes to the train", not Steve's "station
| > comes INTO the train can't happen." You owe me a brandy, and I
| > think Sue deserves one too.
|
| Can I email you one?
I'd rather you won it back, but if you must you can email it's inverse
function, $, and I'll Androclean transform it back to brandy.
|
| Sue'll have to buy her own, though.
|
|
| > I'll agree d^2x/dt^2 is absolute. (For now). 't' better be absolute
| > also.
|
| No, we can't have "t" being absolute. Sagnac's experiment, repeated
| with glass fibers in place of vacuum, shoots the pins right out from
| under absolute time, even at low speeds.
I don't think so. I tried to get Sue to agree to coulomb coupling of the
light with the air outside the cable, putting drag on the light, but she
went into a tirade about dropping the coil from a height of 2 metres.
I agree she'll have to buy her own.
|
|
| > x can be anything it likes or you like. Isaac and Galileo
| > will agree with me. Albert will not. Dunno about Ernst or you, but
| > its 3:2 already. I'd prefer 4:1. Or did you want to bring in your
| > pal, (what's his name? ) Orentz, or something? Laurence, that's it!
| > Or is it Lawrence... I forget. Anyway, do that and I'll bring
| > Johannes Kepler. Not Johannes Brahms, although he's a good musician.
|
| I have no idea what you're talking about here.
Oh, I was putting it to the vote.
See, we have universal time, relative speed of light in NM and the opposite
in SR, relative time and a universal speed of light.
since we can't agree, I was being democratic. You ARE a democrat?
|
| > | > "Examples of this sort ... [yada yada yada] ... be called the
| > | > ``Principle of Relativity''
| > | >
| > | > You wouldn't be taking the customary view and making a
| > | > distinction, would you?
| > |
| > | No, I'm pointing out that in relativity theory, VACUUM has no
| > | velocity. Only observers and observables move. There is nothing
| > | about vacuum that can be observed so it's meaningless to talk
| > | about its velocity.
| >
| >
| > I'd almost agree with you, but that conductor and magnet still
| > bother me, almost as much as "light is always propagated in empty
| > space with a definite velocity c "... I can't help wondering what
| > the speed (or velocity) of [light without a frame] is being compared
| > to. It's pretty easy with the magnet moving INTO the conductor or
| > the conductor moving INTO the magnet, because I think there is some
| > kind of "aura" around the magnet, "lines of fours" I think it's
| > called. And another one, called an electric field. Do electrics
| > graze there like cattle in a meadow? How about an electric meadow?
| >
| >
| > | FIELDS have no velocity, either. A magnetic or electric field
| > | just "is".
|
| > Oh, I agree. Whole-heartedly and with tongue in cheek. Radio doesn't
| > work. Wanna bring in Maxwell and Hertz as well?
|
| I didn't think you'd like that one too much. :-)
Is that another brandy?
|
| On the other hand I think we can assume there are no lurkers here
| because I also didn't think anyone else would like it much, either.
Most lurkers don't like long drawn-out posts, they don't have any attention
span. Those that respond and can't find something to disagree with in one
paragraph give up. Those that don't respond at all... who knows?
Anyway, who wants to continue reading the same material over and over?
"sal" .... wrote in message
| Androcles wrote:
| > "sal" wrote in message
I think you have a safe assumption.
|
| The point is that in E&M as it's now taught, based on SR, the
| "velocity" of the fields (E or B) is never used, and in fact is never
| even defined. The fields "propagate" (splitting a hair) in the sense
| that they appear in places the weren't previously, and disappear from
| places they were, but they don't "move" in the sense that one might
| mean if one said "A moving "B" field will affect a stationary
| electron". It won't. An electron which appears stationary to me will
| be unaffected by any B field I measure. It will, however, move in
| response to an induced E field which I may measure if there happens to
| be a magnet around which is also moving relative to me.
It appears we can agree on something then.
You can 'grow' an E-field with a passing magnet. The question is,
what is the E-field fixed to? The unmoving vacuum?
We can draw the energy with an antenna, the E-field is there.
If a tree falls in a forest...
If an ear moves in a forest, what then?
Ok, so the E-field grows but doesn't move, the B-field grows
but is at rest in the vacuum, which is filled with E and B fields growing
and shrinking, changing sign.
HOWEVER, the magnet takes its field with it, and so does the pith ball.
What is the origin of the field?
I don't care too much for what is "taught". Teachers are people, and
they don't have any better answers than we do. Researchers are useless
if taught. Better to teach how to think, and that can only be by example.
Not all people can think, they only parrot what they've learnt.
|
| The force on a charged particle is
|
| F = q(E + VxB)
Forces only exist between TWO bodies.
F = GMm/r^2.
When the irresistable force meets the immovable object, the other
object moves.
Do a push up. You move, not the floor.
There is something missing in your equation, the implied immovable object.
| (unless I've flipped the sign). Of course, q is the amount of charge,
| V is the velocity of the charge, E and B are as usual,'x' is the cross
| product. But the "velocity" of the _field_ is not present in the
| formula.
Correct. we don't employ the velocity of the plane with the TV
with the electron beam inside the vacuum, it is implied that the motion
of the electron is relative to the tube and so is the force, F= MA+ma.
M is so huge it has neglible acceleration, A = 0, so we write F = ma,
forgetting the recoil.
This forgetfulness is what makes acceleration absolute.
Momentum is conserved, AND it is ALWAYS zero.
| To make this any more clear I'd need to start typing in tensors and
| I'm not going to do that tonight.
|
| (Oh, by the way, _magnets_ can move all they want...)
...taking their field with them.
So can light sources.
So can antennae.
All motion is relative.
We know when an antenna has moved, frequency changes.
You haven't studied Doppler, I'm not going to do that tonight.
It doesn't need tensors though.
| Accelerating magnets and conductors are a mess to solve for. To do it
| right you need to use the retarded integrals of the charge densities
| over space.
Over what? Is that space now, or vacuum?
|
|
| > | Energy moves, and the Pointing vector says where it's going when
| > | it's the energy of the E and B fields. Momentum moves. But the
| > | fields themselves don't "move".
| >
| > Ok. Magnets don't move, if you say so.
|
| No, I didn't say that. Magnets can move. It's just that the field
| ... um ... propagates or evovles, it doesn't "move".
If the car accelerates, so does its passenger. He doesn't get left behind
on a long piece of elastic and exceed the speed of the car to catch up.
If the magnet moves, so does it's field. All motion is relative.
Maybe it is the waiting for the (G) field to move that gives us inertia.
Every atom has its own G-field.
| OK, I'm splitting hairs. The only real point to this is that "motion"
| of the field isn't actually used to determine the effect on anything;
| it's only "motion" of the charges that really matters. And perhaps
| more important, in some cases "motion" of the field is not even well
| defined.
Magnet moves past conductor. FIELD moves INTO conductor.
| Consider a very large fixed magnet with very large pole pieces -- so
| large that the field is perfectly uniform on the pole pieces. Now,
| from the point of view of a tiny observer standing near one of the
| pole pieces, is the field moving or at rest? Remember, the field is
| perfectly uniform, so whether it's moving or not you won't detect any
| change in it. How do you measure its motion?
If he is at rest wrt the magnet, he is at rest wrt its field.
All motion is relative.
| If you say "An electron will accelerate uniformly if the field is
| moving" then I'll ask you how you tell the difference between the
| "moving" uniform magnetic field and a "stationary" uniform magnetic
| field superposed on a "stationary" uniform electric field. Of course,
| the answer is that you can't. So, one can argue (in fact, I just did
| argue) that the B field can't really be considered to be "moving" in
| that case.
Given:
{ There exists a magnetic field. There exists a free electron in the vicinity of the field.}
IF the field is moving OR growing
THEN an electron will accelerate wrt the field.
IF the electron doesn't accelerate wrt the field
THEN the field is not growing OR not moving.
| > I must have moved my fridge
| > to the magnet. I hope you notice I'm not arguing with you. I'm
| > hanging on your every word. It was my fridge that accelerated and
| > decelerated, but the station doesn't come into the train and the
| > fridge doesn't go into the magnet.
| >
| >
| > |
| > | An electron, stationary in a particular FoR, does _not_ react to
| > | any B field as measured in that FoR, because the B fields don't
| > | "move" relative to the electron.
| >
| >
| > Quite so. The fridge comes to the magnet and the train comes into
| > the station. I fully understand.
|
| No, I'm not sure I got the point across.
True, you didn't. I'm quite sure I haven't gotten mine across either.
Still, there has been a little progress.
We can agree ( I think) that Einstein's second postulate, as it is
written verbatim, has no meaning, a moving vacuum or frame of
reference is an absurd concept.
We can agree on Cherenkov radiation, we can agree on a "growing
in place" E- or B-field.
We are currently stuck on the magnetic field moving with the magnet.
You say it shrinks where it was and grows in the new place, I say it moves.
Is there really any difference? I want DC, you want AC. We have both.
I consider DC to be short duration AC, that's all. The electron accelerates
out of the field, taking its own DC (or constant) E-field with it.
Or the B-field accelerates out of the electron, same thing by the PoR.
Reverse (in place) the B-field and the electron comes flying back.
That's even called "flyback" in a TV although really refers to the
DC beam and not an individual electron, and it has a sawtooth waveform.
|
| A moving magnet causes an electric field in its vicinity, and that's
| what a "stationary" electron reacts to. In classical E&M it doesn't
| react to the B field because it isn't moving.
TVs work, generators work, motors work. Even electric clocks work
but cuckoo clocks usually have weights.
Yes, a growing magnetic field causes an electric field in its vicinity,
and that's what an electron reacts to. It goes shooting up the dipole.
Now all we need is a growing electric field with a magnetic monopole
to see how that reacts.
|
| For what it's worth Einstein hated this approach to E&M, or so I have
| read, somewhere. The asymmetry of treating the moving electron and
| the moving B field so differently really bugged him.
|
|
| > | However, electrons _are_ observed to respond to B fields when the
| > | electrons are moving relative to an observer in a frame of
| > | reference in which there is a nonzero B field.
| >
| >
| > Weelllllll... have you consider that electrons don't have frames of
| > reference? Light doesn't, so maybe they don't either.
|
| Sure they do, and they have little eyes which they use to determine
| what direction they're going in, and they're all staring at YOU, RIGHT
| NOW!
|
| Oops, sorry, got carried away there...
|
| Yes, there is a perfectly good FoR associated with each electron
| because they always travel slower than C. The trouble with light is
| that it goes at C (duh) and you run into a zerodivide error trying to
| compute the transform into its frame of reference. So a photon has no
| Lorentz frame, and has no 4-velocity, either. Not _zero_ 4-velocity
| -- rather, _no_ 4-velocity: it's undefined.
Oh, ok. Like light has a speed c that is relative to nothing...
oops, vacuum.
| Huh? Of course the conductor moves, otherwise how's he ever get to
| all the passengers to take their tickets?
He doesn't take my ticket, he punches a vacuum in it and calls it a hole.
It soon fills up with air, though. Nature abhors a vacuum, I'm told.
I wonder why she made so much of it?
| > | There is a lot of confusion on this point, even in reasonably
| > | reputable textbooks.
| >
| >
| > Oh, I'm sure there is. Even I'm confused, I could have sworn my
| > bicycle used a moving magnet to power the lights. Maybe the bike
| > goes around the wheels, huh?
|
| No, acceleration is absolute.
Ah... back to that absolute frame of reference again.
Two cars, drag racing side by side, pedal to the metal,
then one pulls ahead to win the race.
What is the relative acceleration of the losing car?
I bet Newton could tell me...
| I shouldn't have mentioned that bit about the fields... it detracts
| from the overall clarity of the argument, I think.
|
|
| > | Air, on the other hand, has properties that allow one to sensibly
| > | talk about its motion.
| >
| > Of course. The plane flies INTO the air, the kitchen window blows
| > INTO the wind. Air has no motion. See how agreeable I am?
|
| If you wave a kitchen window in the wind, you will cause turbulence in
| the air. Vortices, you know.
|
| You can't have vortices in the vacuum, or so most people believe.
|
| QED.
Now you are bringing belief into it. The turbulence caused
by the moon should produce vortices in the aether, and then light
passing through would refract and shimmer like a car roof on a hot day.
I can't see why there are no vortices in vacuum, though...
Next you'll be telling me Harry Potter doesn't exist, and most people
have SEEN him.
|
|
| > | > But you are correct, the postulate doesn't say what happens if
| > | > the air is in a state of motion relative to the
| > | > receiver. Einstein's postulate doesn't say what happens if the
| > | > vacuum is in a state of motion relative to the receiver either,
| > |
| > | As I said, vacuum can't "move". Air can.
| >
| >
| > Ah, but it doesn't. It COULD, but the plane flies INTO the air, like
| > the train comes INTO the station. The air doesn't come to the plane
| > (of course).
|
| No, it comes _into_ the plane, through the air intakes, where it's
| compressed and forced into the cabin, where it dries out everybody's
| membranes.
Tell the pilot to fly though a cloud. He won't bump INTO it.
|
|
| > The plane accelerated and so did the house when it only
| > seemed the wind was blowing through the kitchen window.
| >
| >
| > | > so no harm, no foul. What is the speed of light relative to? The
| > | > empty space.
| > |
| > | Nope, it's relative to an observer.
| >
| >
| > That's not what Albert said. He didn't mention any observer in his
| > second postulate. Maybe you have some other theory that isn't
| > Albert's. Has it been published? I'd like to read it. I can't
| > discuss some other theory until I've read it, sorry.
|
| Einstein's 1905 paper was very original, and packed choc full of
| information and ideas, but it's not a stunning masterpiece of
| clarity.
|
| Just how do you think the vacuum measures the velocity of the light
| passing by?
You'll have to ask Albert that. I wanted to know how the light measures
the velocity of the vacuum passing by, or other light coming toward it,
but you said the light has no frame to mount a speedometer into.
|
| And again, how does an observer measure the velocity of empty space,
| if he's trying to figure out how fast light is going relative to it?
Dunno... Albert musta done it somehow, cos every child at school knows...
I really don't mind people enjoying mathematics, but it irks me when
they start calling it "physics" and pretending to know something about the
world around us. There are enough real mysteries to solve without
adding fake ones to them.
In other words you want to jump-start straight from the Lorentz
transforms and you don't give a hoot how they were derived.
A religious-like belief, unfounded by any observation.
You can do that in mathematics, which you enjoy. I have no objection
in postulating ANYTHING in mathematics. You can say anything you like
and as long as it is consistent it is fine. Space got itself curved when Riemann
changed Euclid's fifth postulate.
| > and he's got all of Albert's math.
|
| No, I don't. Einstein had a much, much stronger grasp of the math
| than I ever will, but you'd need to get into his later papers to
| really see it.
|
| Try reading his 1916 GR papers, "Foundations" and "Hamilton's
| Principle".
They are math papers, not physics papers. Einstein stopped his
scientific career with the photo-electric effect and nevermore produced
any physics.
Einstein's intent is clear to me, the equation
½[tau(0,0,0,t)+tau(0,0,0,t+x'/(c-v)+x'/(c+v))] = tau(x',0,0,t+x'/(c-v))
makes it so.
c-v and c+v are the Galilean relative velocities, the 1/2 and the function tau
are there for his definition of time. It fails mathematically because it results
in a contradiction, "It follows, further, that the velocity of light c cannot be
altered by composition with a velocity less than that of light.
For this case we obtain V = (c+w)/(1+w/c) = c."
It doesn't have a ghost of a chance in Sagnac.
We are expected to tolerate a belief that the speed of light is c in all frames
of reference, for which you require a religious-like faith having acquired
it yourself, rather than Einstein's definition of time.
I shall continue to try to reason with and fight opponents of science,
there is nothing in Einstein's paper that is remotely scientific.
It is a mathematical paper, I question the postulates, I question
the definition and I certainly find his use of (c-v) to be contradictory
to (c-v)/(1-v/c).
| > The air doesn't move. The train can come into the station, but has
| > to decelerate. The station doesn't accelerate or decelerate,
| > remember? Air can't either, it covers the entire globe. If it
| > accelerated, it would have to move,
|
| Cripes, where have you been for the last few decades? Air's been
| moving all over the place lately.
|
| Ever hear of a "jet stream"? That's what it uses when it's really in
| a hurry.
Of course. I'm not applying real physics, I'm applying a postulate in
a mathematical paper. The velocity of sound is Mach1 in all frames
of reference for you, and for disciples of Einstein we establish by
definition that the ``time'' required by sound to travel from A to B
equals the ``time'' it requires to travel from B to A.
I never intended to apply it to anything like Sagnac, but I could.
I just need a penny whistle and gentle flow of air through a plastic hose.
I'll get a beat frequency as the sound goes in opposite directions around
the pipe and that'll "prove" my theory.
I thought you said you enjoyed mathematics. I do too. :-)
|
| > and if it moved it would
| > disappear down a Chinese coal mine and come back up through a
| > Pennsylvania coal mine (or the other way round). The plane flies
| > INTO the air, so does the kitchen window if you leave it open.
| >
| >
| >
| > | How do you build an anemometer that shows how fast vacuum is
| > | going?
| >
| >
| > Dunno... I'll have to think about it.
|
| Do that. If you can't build one, even in principle, then you can't
| talk sensibly about how fast the vacuum is moving, and without that,
| you can't talk about how fast something is moving relative to the
| vacuum.
Oh, in PRINCIPLE! I thought you wanted a real one.
I can do it in principle with no trouble at all.
Remember that jet stream you told me about?
If you fly from Boston to Paris in a plane that is flying in the jet
stream, you'll get there faster than you expected.
So just look at your watch and work out the speed of the jetstream.
Now, in PRINCIPLE, if we go to Alf-er-sent-us-a-saurus or whatever
it's called in a spaceship and time the journey, and if that time appears
to be less that we thought it would be from a Newtonian calculation,
by (say) t - t * sqrt(1-v^2/c^2) then we must have been carried along
by the rocket stream in the vacuum. Easy in principle.
Now you can see the true CAUSE of time dilation. You thought it was
magic, I bet.
|
| > I agreed with you and not
| > with Albert. Vacuum can't move. How do you measure the speed of
| > light in a vacuum to test Albert's second postulate?
|
| You need a big blobby pulse consisting of many photons, so one
| observer can use up some of the photons and still leave some for the
| next observer, and you need at least two observers who are stationary
| relative to each other, and they must have clocks which are in sync,
| and you know the rest of the drill.
|
| If you want to economize on observers you can use just one along with
| a mirror, but you need to be sure the mirror's stopped relative to the
| single observer.
You'd better pick a day when the rocket stream has move out to the orbit
of Neptune, then. Otherwise it'll carry the light along with it.
The jet stream carries sound along faster, as you know.
Tell ya what! Instead of a mirror let's put the light in at both ends of a
fibre optic cable at the same time! We could even cut the cable in the
middle and put some vacuum there in a hollow tube.
There's the "anemometer" you wanted. Well done Sagnac!
| > You'll have to
| > make sure the vacuum isn't moving, right? If it moved it might
| > carry the light along with it, like a river carries a boat
| > downstream.
|
| No, there's no drag associated with moving vacuum, in part because it
| doesn't move.
You forget the rocket stream. It'll carry to a distant star and your clock
will show it.
| > Sue reckons the vacuum has the properties of
| > permittivity and permeability, she loves to talk about those. Keeps
| > talking about alpha and mu0... I don't think they exist. mu1, maybe.
|
| So maybe Sue can tell you how to measure the velocity of the vacuum.
| I sure can't, as far as I know it can't be done.
It's easy, I worked it out in principle.
You'll have time if you quit writing silly stories about Sagnac and get
down to some real physics. You can't understand Sagnac without
doppler anyway.
[snip doppler, sal's not interested]
> | So phi's an angle. Which angle is it?
| >
| >
| > Well it would be, it's an argument to a cosine function. It's
| > somewhere between 0 and 360 degrees, I think. But it should work
| > above and below that and the cosine function should yield between -1
| > and +1.
|
| Right, but which angle is it?
|
| Einstein made a rather surprising choice for the angle he would use in
| that formula, if I recall correctly, but I don't recall off hand which
| angle he used. Do _you_ know which angle it was?
Yeah... (fixed font needed)
_________---> v (source)
\ A
\
\
\
\
___B \___ v < --- (observer)
Instead of A he used B. He switched the source and observer around.
He does that to keep his readership on it's toes, the more confused
they are the better. ONLY the observer can move.
"it follows that if an observer is moving with velocity v relatively to an infinitely distant source of light of
frequency nu, in such a way that the connecting line ``source-observer'' makes the angle phi with the velocity of the
observer referred to a system of co-ordinates which is at rest relatively to the source of light, the frequency nu' of
the light perceived by the observer is given by the equation".
Sources of light never move toward an observer, that's to preserve the constancy of the
speed of light in a vacuum. He likes infinite distances too. Heaven only knows how you can see
something infinitely far away. Meaningless drivel as best as I can tell.
|
|
| > | Angle between the emitted ray, or the received ray, and ... what?
| > | There's more than one way to set it up and the answers are
| > | different depending on how you do it.
Ya mean angle A is not equal to angle B?
Or the source can't move?
| >
| >
| > Yep. I tried to tell Albert that very same thing. In the end I had
| > to figure out what he meant. He didn't put cos(phi) in beta = 1/
| > sqrt(1 - [v.cos(phi)/c]^2) either. Maybe he overlooked it.
|
You didn't answer that!!!
> | > | Sorry, I think I missed that. Could you repeat the
| > | > | definition, please?
|
| > | > Sure. The ``time'' required by SOUND to travel from A to B
| > | > equals the ``time'' it requires to travel from B to A.
|
| [ snip dupes ]
|
| > | Sorry, that doesn't define "time", it just tells me how it behaves
| > | in one very specific case.
| >
| >
| > You'd better tell Albert, then. He uses that stuff you call "light"
| > to replace my "sound".
|
| Yeah, he didn't do a very explicit job of defining "time" in that
| paper.
LOL! That is the WHOLE BASIS of time dilation.
It's the reason for the 1/2, the reason for the function tau,
how tau = (t-v.cos(phi)x)/ sqrt( 1-v.cos(phi)^2) is found.
Except he forgot the cos(phi), but that doesn't matter as long as
you believe him, you that likes math and reads modern approaches
to the subject.
The observer moves through the vacuum, light COULD be coming from
straight ahead, no need for v.cos(phi) in the cuckoo transforms.
Next the teacher figures out that the cuckoo transforms make
the speed of light 'c' in all frames of reference and that becomes
the new postulate YOU are thoroughly brainwashed with,
so you use it to derive your own cuckoo transforms. And of course
it works! Total circularity always does.
| I think he directed the paper mostly at people who already
| knew that "time" was a coordinate in the model, and it was what clocks
| measure in the real world, and that testing the model would consist of
| comparing clock readings to predicted coordinate values and seeing if
| they lined up.
Phooey. He was a patent office clerk looking at submissions for clocks
and watches, read H.G. Wells' "Time Machine" and got a fetish for time.
He was careful to include Maxwell's aether and Lorentz's answer to
MMX. He wrote a paper and it impressed a few people.
Not Michelson, he was still plugging away for the US Navy.
It was E = mc^2 that really put him on the map, bombs impress the public.
Fermi and Oppenheimer would have got there without him anyway.
|
| > Personally I think it is rather daft, but
| > you can't have time dilation without it. Remember that horrible
| > equation we discussed?
| > ½[tau(0,0,0,t)+tau(0,0,0,t+x'/(c-v)+x'/(c+v))] =
| > tau(x',0,0,t+x'/(c-v)) ?
|
| No, I've blocked it out.
Head buried in the sand, but still able to mutter cuckoo transforms huh?
|
| > That '½' is there to compute the time it takes for light to go from
| > A to B. The round trip from A to B and back again cut in half. I'm
| > using sound instead. I cribbed from Albert. Naughty of me.
| >
| >
| > | [ snip ]
| > |
| > | > | > Concorde never once exceeded Mach1,
| > | > |
| > | > | Really? So it was all a hoax, after all?
| > | >
| > | >
| > | > Of course. Mach1 = (Mach1 +w)/(1+w/Mach1) If you have two
| > | > Concordes crossing the Atlantic and going in opposite directions
| > | > their closing speed is given by V = (v+w)/(1+vw/Mach1),
| > |
| > | What are they doing, playing "chicken"?
| > |
| > | OK, I've got a question for you.
| > |
| > | How do you handle the Sagnac effect in emission theory?
| >
| >
| > Emission theory is only about light in EMPTY space.
|
| I thought you'd said previously that in a physical medium such as air
| or glass, light travels at SoL in the air or glass, relative to that
| object. At least, that's what you said when we were arguing about
| redshifts and spectroscopes, a long time back. Are you disavowing
| that now?
I think I said at a speed characteristic of the medium. You'll need
to quote me to get a brandy back, IF I mislead you unintentionally.
I don't recall the exact phrase I used. c/n relative to the medium
is what I mean today and meant then.
| It doesn't help, anyway. The Sagnac effect works just fine using
| _evacuated_ tubes, too. (You know, tubes filled with empty space,
| which you just said emission theory _is_ about.)
Emission theory is what Einstein used to derive his cuckoo transforms
before he added his own definition of time.
Sagnac has air on the OUTSIDE, dragging the light on the inside.
You are seeing conservation of momentum, nothing more.
| > Sagnac space isn't empty.
|
| The experiment's been done both ways: empty space and non-empty
| space. The result is much the same: the time to go around the ring
| is different one way than the other way, when the ring is rotating.
| It's quite strange.
You are back to a universal frame, then. Of course the Earth's G-field
MAY play a part in it, but that won't be funded for research by bright
young minds all the time the governments of this world swallow the
Einstein legend. Ritz thought gravity was a spin off from EM but never
completed his work before he died, and now there is no gravity, only
curved spacetime. Who needs a GUT anyway?
|
| > My new "sound" theory with built-in time
| > dilation isn't emission theory either. Looks like you snipped it,
| > though.
|
| Sorry; I thought we were done with it, and the wrapping had gotten
| totally mangled on that section. Anyhow, it's just SR with mach1 in
| place of C, right?
Yep. Same postulates, same math, only the names are changed to protect
the innocent. I wasn't serious about it, but Sagnac with sound....you
might be. Plastic hose and a single sound transducer, blow air through.
Speed of sound clockwise, m1 + v. Counterclockwise, m1-v.
Result, a beat frequency, so listen hard or put an oscilloscope and a
microphone on the wall.
Henri Wilson
80973000 words.
You might be pleased to hear that somebody actually read most of your book, A.
..without laughing...Hohohahah!
Lay off that bourbon, will yu!
Autymn D. C.
have got -> have gotten
Learn how to snip, and how to use a spare reference frame.
Androcles
"Henri Wilson" <H@..> wrote in message
|
| 80973000 words.
|
| You might be pleased to hear that somebody actually read most of your
book, A.
| ..without laughing...Hohohahah!
|
| Lay off that bourbon, will yu!
|
| HW.
Is that all? Some were snipped.
Are you sure it was words and not bytes?
It fits in 64 Kbytes.
Androcles
sal
I'm just including the few bits that I'm answering in this post. If
time allows I may respond to other bits in the future.
On Wed, 27 Jul 2005 22:54:21 +0000, Androcles wrote:
>
> "sal" <pragm...@nospam.org> wrote in message
> news:pan.2005.07.27....@nospam.org...
> | On Tue, 26 Jul 2005 02:31:38 +0000, Androcles wrote:
> |
[ ... ]
> |
> | This is semantic logic-chopping, really. Relative velocity,
> | closing velocity -- either one works for me. Either way, it's the
> | time derivative of a length, rather than the time derivative of
> | the location of an object, and as such it's not a "velocity" at
> | all in the sense that it doesn't tell you how fast something's
> | going.
>
> Can't agree. It isn't possible to state how fast anything is going
> without a reference (usually implied) as to what that speed is
> relative too.
To measure the velocity of an object you need to know the time and
location of two points on its path, in some particular frame of
reference. One point won't do, because you need to evaluate a
derivative in the "real world" and that always takes two points (plus
the assumption that the object's motion is uniform).
Like, say, you might find that at time 1 its X coordinate is 3, at
time 2 its X coordinate is 16, and its Y and Z coordinates are fixed
at zero. From that you'd conclude that it's traveling at
(16 - 3)/(2 - 1) = 13
If c=1, then it's moving at 13C. (Give it a ticket; it's breaking the
rules.)
You can use scope probes and rulers, or synchronized clocks, or
whatever you want to get your two readings. But you can't get away
from the fact that you need two readings.
The velocity is then whatever you measured, as viewed by any observer
who is at rest with respect to the "particular frame of reference".
And you can't get away from the fact that the "vacuum" isn't anywhere
in particular, doesn't have a particular time attached to it, and can
never provide you with the events you need to determine how fast it's
going.
Relative speed (or closing speed or whatever you care to call it),
viewed from a particular frame of reference, can be obtained by plain
old vector addition, or by explicitly subtracting the positions and
then differentiating, which will give the same result.
Speed that _would_ _be_ measured by an observer in some other FoR must
be found using composition of velocities, of course.
> | If two cars collide head-on, each going 60 MPH (which is legal
> | again in this country), then as viewed by an observer by the side
> | of the road each car had speed = 60 MPH (and velocity = +/- 60
> | depending on the direction, if we use the convention that speed =
> | abs(velocity)). The "closing speed" or "relative speed" or
> | whatever you want to call it is 120 MPH, but it's not the velocity
> | of any object, as viewed by our roadside observer, because it's
> | not the derivative of a position.
>
> You display the same confusion that put Galileo under house arrest.
I thought they arrested him for not giving God proper credit in his
papers.
> Why do people think the Earth is the absolute frame of reference
> against which this 60 MPH is to be measured? The car is travelling
> around the Sun, a distance of approximately 93,000,000 * 2*pi miles,
> in one year. In the frame of the fixed stars your 60 mph is a
> relative speed. The Earth moves. ALL speeds are relative. No
> exceptions. You've adopted what Einstein called the "customary
> view". His magnet and conductor are hurtling around the solar system
> too, at 0.0001c in the "empty space". That should make it quite
> possible to detect relativistic effects easily, if there were any.
> Radio transmission to spacecraft near Saturn, relative to the
> spacecraft, are sent at between 0.9999c and 1.0001c in empty space.
In the FoR of an observer on Earth, you mean, right?
In the craft's FoR it would seem different.
Either way we'd need somebody out in space with a clock to tell us
when the signal passed him by in order to confirm the velocity, of
course. Otherwise it's just my-theory-against-yours. You can't
determine a velocity with just one point.
[ ... snip (but I read it first...)... ]
> | > | Does an electron falling toward the Earth radiate?
> | >
> | > I think it's called Cherenkov radiation, but you only get it in
> | > a medium.
> |
> | No, Cherenkov radiation is what you get when a charged particle
> | travels faster than SoL in a medium. Has nothing to do with
> | acceleration (save that it's accompanied by rather rapid
> | deceleration).
>
> No, No, NO!
> Cherenkov radiation is what you get when a charged particle travels
> faster than SoL in a medium.
>
> Do you always agree by saying "No"? It must drive your wife crazy.
Yup.
> Perhaps she's used to it...
Nope.
[ ... ]
> | No, I have no shrine to Einstein, I'm not even on a first name
> | basis with him. I have to dig out one of his books every once in
> | a while to answer some post of yours, but I don't spend nearly as
> | much time following him as you do, I suspect... :-)
> |
>
> What was all that stuff you wrote about on Sagnac, then? It's not
> even a moving vacuum fibre...
It's 'cause I got in an embarrassing corner over in fr.sci.physique in
an argument over contraction on a rotating disk, and someone claimed
the Sagnac effect proved his point. I went and thought about it and
came up with what I felt was a nice way of looking at it. I put that
into a web page. That's it.
If you want to know about the experiments that have been done and what
devices are available, google it, or look in an encyclopedia.
Britannica has something on it, for instance. I'm not signing up to
do your research for you.
> | I enjoy the math.
>
> Do you? Cool! What is the fewest number of colours needed for a map,
> no
> two countries with the same colour to share a border, all countries to
> share a border with another, 1) on a plane sheet of paper, (4
> colours)
And on a torus it's ... um ... at least 5, for sure, 'cause I can
think of an example that needs 5. But is it exactly 5, or is it 6?
Not sure, my visualization the 6-color example has lost its vertical
hold and I'm not sure if it's correct.
> 2) on a Mobius strip,
Don't know. (Do you?) Certainly at least 4 because that can be done
with a "local" example that works on anything 2-dimensional. But is
it more than 4? Hmmm...
> 3) on a Klein bottle,
Ouch! Don't know, and can't even picture it.
> 4) on a sphere ?
Four again. Puncture the sphere, and it's isomorphic to the plane.
Puncture it in the middle of one country and you're done -- any
example requiring more than 4 colors would map 1:1 onto the plane,
where we know it's only 4.
> Assume the surface is transparent, same colour shows through the other
> side.
That makes a difference to the Mobius strip and the Klein bottle, but
not to the plane, sphere, or torus.
> | I'm also getting a kick out of reading Stephen Hawking's "Une
> | Brève Histoire du Temps" which I picked up used for a couple
> | bucks. It's a very light read but it's fun. It's more of a
> | history-of-science book than a science book, which I suppose
> | should have been apparent from the title.
>
> Yeah... I read the English translation many years ago. Hawking's
> haughty first wife didn't like me much, she thought he shouldn't
> have a beer. Can't think why she brought him into a bar...
Seriously??
I can believe she didn't think he should drink. Can't do his CNS any
good.
> I'd have to have Coca Cola with bourbon.
UGH
[ ... ]
> | The force on a charged particle is
> |
> | F = q(E + VxB)
>
> Forces only exist between TWO bodies. F = GMm/r^2. When the
> irresistable force meets the immovable object, the other object
> moves. Do a push up. You move, not the floor. There is something
> missing in your equation, the implied immovable object.
The observer who measures the field is the one whose observation of
the particle provides the V in the equation.
There isn't anything to push "against" in the Lorentz force law.
> | (unless I've flipped the sign). Of course, q is the amount of
> | charge, V is the velocity of the charge, E and B are as usual,'x'
> | is the cross product. But the "velocity" of the _field_ is not
> | present in the formula.
>
> Correct. we don't employ the velocity of the plane with the TV with
> the electron beam inside the vacuum, it is implied that the motion
> of the electron is relative to the tube and so is the force, F=
> MA+ma. M is so huge it has neglible acceleration, A = 0, so we write
> F = ma, forgetting the recoil. This forgetfulness is what makes
> acceleration absolute. Momentum is conserved, AND it is ALWAYS zero.
Earth is treated as an infinite momentum source/sink, of course.
I still think acceleration is absolute.
[ ... ]
> | You can't have vortices in the vacuum, or so most people believe.
> |
> | QED.
>
> Now you are bringing belief into it.
Someplace I ran across a variant on Ritz-Fox that claimed vortices in
the vacuum normalized the velocity of light, providing a finite
extinction length even in "vacuum". But I couldn't find the reference
again later so I couldn't quote it.
Too bad.
[ ... ]
> | > | How do you handle the Sagnac effect in emission theory?
> | >
> | > Emission theory is only about light in EMPTY space.
> |
> | I thought you'd said previously that in a physical medium such as
> | air or glass, light travels at SoL in the air or glass, relative
> | to that object. At least, that's what you said when we were
> | arguing about redshifts and spectroscopes, a long time back. Are
> | you disavowing that now?
>
> I think I said at a speed characteristic of the medium. You'll need
> to quote me to get a brandy back, IF I mislead you
> unintentionally. I don't recall the exact phrase I used. c/n
> relative to the medium is what I mean today and meant then.
That's what I thought.
In that case, wouldn't a fixed observer watching a rotating fiber
optic ring, where the ring's tangential velocity is V, see the light
traveling around it one way at
U+ = c/n + V
and the other way at
U- = c/n - V
??
Sure looks like it to me.
And that leads very easily to the conclusion that there is no Sagnac
effect.
> | It doesn't help, anyway. The Sagnac effect works just fine using
> | _evacuated_ tubes, too. (You know, tubes filled with empty space,
> | which you just said emission theory _is_ about.)
>
> Emission theory is what Einstein used to derive his cuckoo
> transforms before he added his own definition of time. Sagnac has
> air on the OUTSIDE, dragging the light on the inside. You are seeing
> conservation of momentum, nothing more.
Say that again? You'll need to spell that out because I didn't get it.
The version with evacuated tubes emits the light in vacuum, and
reflects it off of mirrors in vacuum.
The version with a fiber optic ring emits the light directly into the
fiber, and the whole lot goes around together.
> | > Sagnac space isn't empty.
> |
> | The experiment's been done both ways: empty space and non-empty
> | space. The result is much the same: the time to go around the
> | ring is different one way than the other way, when the ring is
> | rotating. It's quite strange.
>
> You are back to a universal frame, then.
That's one way to explain it. But then you run into trouble with
MMX.
Androcles
|I can't do this justice tonight, but here are a couple of comments.
|
| I'm just including the few bits that I'm answering in this post. If
| time allows I may respond to other bits in the future.
yeah, yeah... You'll never keep up with me.
|
|
| On Wed, 27 Jul 2005 22:54:21 +0000, Androcles wrote:
|
| >
| > "sal" <pragm...@nospam.org> wrote in message
| > news:pan.2005.07.27....@nospam.org...
| > | On Tue, 26 Jul 2005 02:31:38 +0000, Androcles wrote:
| > |
| [ ... ]
| > |
| > | This is semantic logic-chopping, really. Relative velocity,
| > | closing velocity -- either one works for me. Either way, it's the
| > | time derivative of a length, rather than the time derivative of
| > | the location of an object, and as such it's not a "velocity" at
| > | all in the sense that it doesn't tell you how fast something's
| > | going.
| >
| > Can't agree. It isn't possible to state how fast anything is going
| > without a reference (usually implied) as to what that speed is
| > relative too.
|
| To measure the velocity of an object you need to know the time and
| location of two points on its path, in some particular frame of
| reference. One point won't do, because you need to evaluate a
| derivative in the "real world" and that always takes two points (plus
| the assumption that the object's motion is uniform).
If you know the length of a boxcar, you can count them at a railroad
crossing and know the length of the train. When the locomotive passes,
look at your watch, and when the last car passes, look at your watch
again.
The speed of the train at 8:50 am on a Monday morning in the summer
of 2000 at Leetsdale, Pa. was 11 mph. I know, I was there waiting to go
to work, it was hot in the car and I had nothing to do but wait,
sweltering.
The train was 0.9 miles long and took 4 minutes and 54 seconds,
which is forever when waiting at a RR crossing, low on gas and the sun
blazing down.
|
| Like, say, you might find that at time 1 its X coordinate is 3, at
| time 2 its X coordinate is 16, and its Y and Z coordinates are fixed
| at zero. From that you'd conclude that it's traveling at
|
| (16 - 3)/(2 - 1) = 13
|
| If c=1, then it's moving at 13C. (Give it a ticket; it's breaking the
| rules.)
|
| You can use scope probes and rulers, or synchronized clocks, or
| whatever you want to get your two readings. But you can't get away
| from the fact that you need two readings.
|
| The velocity is then whatever you measured, as viewed by any observer
| who is at rest with respect to the "particular frame of reference".
|
| And you can't get away from the fact that the "vacuum" isn't anywhere
| in particular, doesn't have a particular time attached to it, and can
| never provide you with the events you need to determine how fast it's
| going.
|
| Relative speed (or closing speed or whatever you care to call it),
| viewed from a particular frame of reference, can be obtained by plain
| old vector addition, or by explicitly subtracting the positions and
| then differentiating, which will give the same result.
|
| Speed that _would_ _be_ measured by an observer in some other FoR must
| be found using composition of velocities, of course.
"Of course" nothing, absolute nonsense.
|
|
| > | If two cars collide head-on, each going 60 MPH (which is legal
| > | again in this country), then as viewed by an observer by the side
| > | of the road each car had speed = 60 MPH (and velocity = +/- 60
| > | depending on the direction, if we use the convention that speed =
| > | abs(velocity)). The "closing speed" or "relative speed" or
| > | whatever you want to call it is 120 MPH, but it's not the velocity
| > | of any object, as viewed by our roadside observer, because it's
| > | not the derivative of a position.
| >
| > You display the same confusion that put Galileo under house arrest.
|
| I thought they arrested him for not giving God proper credit in his
| papers.
|
| > Why do people think the Earth is the absolute frame of reference
| > against which this 60 MPH is to be measured? The car is travelling
| > around the Sun, a distance of approximately 93,000,000 * 2*pi miles,
| > in one year. In the frame of the fixed stars your 60 mph is a
| > relative speed. The Earth moves. ALL speeds are relative. No
| > exceptions. You've adopted what Einstein called the "customary
| > view". His magnet and conductor are hurtling around the solar system
| > too, at 0.0001c in the "empty space". That should make it quite
| > possible to detect relativistic effects easily, if there were any.
| > Radio transmission to spacecraft near Saturn, relative to the
| > spacecraft, are sent at between 0.9999c and 1.0001c in empty space.
|
| In the FoR of an observer on Earth, you mean, right?
NO I DON'T! I mean in the FoR of the empty space, the same
empty space that Einstein says the velocity of light is c in.
If you want something as an anchor, in the frame of reference
of an observer on Mars as the signal hurtles past.
| In the craft's FoR it would seem different.
Of course it would. Earth is approaching Saturn at 0.0001c
a little over once a year, the signal leaves Earth at c and hits
the spacecraft at 1.0001c, then six months later at 0.9999c.
|
| Either way we'd need somebody out in space with a clock to tell us
| when the signal passed him by in order to confirm the velocity, of
| course. Otherwise it's just my-theory-against-yours. You can't
| determine a velocity with just one point.
Easily done. Have the spacecraft time-stamp a bounced signal,
we don't need a person.
|
| [ ... snip (but I read it first...)... ]
So you agreed with it, or you would have said something.
Waste of time, especially for someone that claims to be short of it.
|
| If you want to know about the experiments that have been done and what
| devices are available, google it, or look in an encyclopedia.
| Britannica has something on it, for instance. I'm not signing up to
| do your research for you.
According to Lorentz, the ring becomes elliptical as it is compressed
by aether, the Earth hurling through space, but the circumference
will not change.
According to Einstein, the circumference will change when you turn
the light on.
" It is at once apparent that this result still holds good if the clock
moves
from A to B in any polygonal line, and also when the points A and B
coincide."
Both were crazy.
|
|
| > | I enjoy the math.
| >
| > Do you? Cool! What is the fewest number of colours needed for a map,
| > no
| > two countries with the same colour to share a border, all countries
to
| > share a border with another, 1) on a plane sheet of paper, (4
| > colours)
|
| And on a torus it's ... um ... at least 5, for sure, 'cause I can
| think of an example that needs 5. But is it exactly 5, or is it 6?
| Not sure, my visualization the 6-color example has lost its vertical
| hold and I'm not sure if it's correct.
|
|
| > 2) on a Mobius strip,
|
| Don't know. (Do you?) Certainly at least 4 because that can be done
| with a "local" example that works on anything 2-dimensional. But is
| it more than 4? Hmmm...
Six, but I don't have the proof to hand.
|
| > 3) on a Klein bottle,
|
| Ouch! Don't know, and can't even picture it.
(fixed font)
Connect the edges as shown, A to B, B to B.
__________
| open |
| |
| |
open open plain plane
| |
| |
|___open__|
___A_>_B__
| |
| |
| |
open open Moebius strip
| |
| |
|__B_<_A__|
___A_>_B__
| |
c c
| |
v v torus
| |
D D
|__A_>_B__|
___A___
/ \
| |
| |
A A sphere
| |
| |
\____A___/
___A_>_B__
| |
C C
| |
v v Klein bottle
| |
D D
|__B_<_A__|
|
| > 4) on a sphere ?
|
| Four again. Puncture the sphere, and it's isomorphic to the plane.
Correct.
| Puncture it in the middle of one country and you're done -- any
| example requiring more than 4 colors would map 1:1 onto the plane,
| where we know it's only 4.
|
|
| > Assume the surface is transparent, same colour shows through the
other
| > side.
|
| That makes a difference to the Mobius strip and the Klein bottle, but
| not to the plane, sphere, or torus.
|
|
| > | I'm also getting a kick out of reading Stephen Hawking's "Une
| > | Brève Histoire du Temps" which I picked up used for a couple
| > | bucks. It's a very light read but it's fun. It's more of a
| > | history-of-science book than a science book, which I suppose
| > | should have been apparent from the title.
| >
| > Yeah... I read the English translation many years ago. Hawking's
| > haughty first wife didn't like me much, she thought he shouldn't
| > have a beer. Can't think why she brought him into a bar...
|
| Seriously??
Yeah, Sussex U at Brighton, many years ago. I was reading QM.
Hawking was on a gurney, his wife pushed him around. He could speak
normally then. I had no idea who he was, but he came up to our group
and started chatting physics so I offered to buy him a beer, I needed a
refill anyway.
His wife said to me "Don't you know who this is?" with her snooty nose
in the air, and I replied "Nope".
She says "He's Steven Hawking!" and pushed him away.
I'd have bought her one too. Oh well...
Britain is still very much a class-conscious society, I'm
still 1,243,676th in line for the throne.
No, wait... my neighbour George passed away, aged 84, make that
1,243,675th.
|
| I can believe she didn't think he should drink. Can't do his CNS any
| good.
|
|
| > I'd have to have Coca Cola with bourbon.
|
| UGH
|
I thought that might make you cringe.
| [ ... ]
|
| > | The force on a charged particle is
| > |
| > | F = q(E + VxB)
| >
| > Forces only exist between TWO bodies. F = GMm/r^2. When the
| > irresistable force meets the immovable object, the other object
| > moves. Do a push up. You move, not the floor. There is something
| > missing in your equation, the implied immovable object.
|
| The observer who measures the field is the one whose observation of
| the particle provides the V in the equation.
|
| There isn't anything to push "against" in the Lorentz force law.
You mean the TV doesn't go backwards in the FoR of the electron?
I thought it did until the electron hit the tube face and knocked
it forward again, conserving momentum.
|
|
| > | (unless I've flipped the sign). Of course, q is the amount of
| > | charge, V is the velocity of the charge, E and B are as usual,'x'
| > | is the cross product. But the "velocity" of the _field_ is not
| > | present in the formula.
| >
| > Correct. we don't employ the velocity of the plane with the TV with
| > the electron beam inside the vacuum, it is implied that the motion
| > of the electron is relative to the tube and so is the force, F=
| > MA+ma. M is so huge it has neglible acceleration, A = 0, so we write
| > F = ma, forgetting the recoil. This forgetfulness is what makes
| > acceleration absolute. Momentum is conserved, AND it is ALWAYS zero.
|
| Earth is treated as an infinite momentum source/sink, of course.
|
| I still think acceleration is absolute.
Well, you would. You have an absolute frame of reference for it to be
absolute in, the empty space c is constant and absolute in.
Einstein has relative time and absolute space, Newton has absolute
time and relative space.
|
| [ ... ]
|
| > | You can't have vortices in the vacuum, or so most people believe.
| > |
| > | QED.
| >
| > Now you are bringing belief into it.
|
| Someplace I ran across a variant on Ritz-Fox that claimed vortices in
| the vacuum normalized the velocity of light, providing a finite
| extinction length even in "vacuum". But I couldn't find the reference
| again later so I couldn't quote it.
|
| Too bad.
No great loss to me.
| [ ... ]
|
| > | > | How do you handle the Sagnac effect in emission theory?
| > | >
| > | > Emission theory is only about light in EMPTY space.
| > |
| > | I thought you'd said previously that in a physical medium such as
| > | air or glass, light travels at SoL in the air or glass, relative
| > | to that object. At least, that's what you said when we were
| > | arguing about redshifts and spectroscopes, a long time back. Are
| > | you disavowing that now?
| >
| > I think I said at a speed characteristic of the medium. You'll need
| > to quote me to get a brandy back, IF I mislead you
| > unintentionally. I don't recall the exact phrase I used. c/n
| > relative to the medium is what I mean today and meant then.
|
| That's what I thought.
|
| In that case, wouldn't a fixed observer watching a rotating fiber
| optic ring, where the ring's tangential velocity is V, see the light
| traveling around it one way at
|
| U+ = c/n + V
|
| and the other way at
|
| U- = c/n - V
|
| ??
Yep. I'm no aetherialist or relativist, so what I do is open out
the fibre into a straight line and inject light into both ends
simultaneously. In Sagnac we truly have simultaneity, of course.
Now to an observer moving relatively to the fibre, the speed
of light is c+v one way and c-v the other.
Now we are back to the train experiment, light leaves at 0 and 80
It travels the full length of the train (or fibre) in 4 seconds one
way and 16 seconds the other, bounces at each end.
Fibre moving left to right.
Light starting from the left.
½[tau(0,0,0,t)+tau(0,0,0,t+x'/(c-v)+x'/(c+v))] = tau(x',0,0,t+x'/(c-v))
½[tau(0,0,0,0)+tau(0,0,0,20)] = tau(32,0,0,16).
Light starting from the right:
½[tau(x',0,0,t)+tau(x',0,0,t+x'/(c-v)+x'/(c+v))] = tau(0,0,0,t+x'/(c+v))
½[tau(32,0,0,0)+tau(32,0,0,20)] = tau(0,0,0,4).
Solve tau.
| Sure looks like it to me.
|
| And that leads very easily to the conclusion that there is no Sagnac
| effect.
|
It leads to making nonsense out of your relativity.
|
| > | It doesn't help, anyway. The Sagnac effect works just fine using
| > | _evacuated_ tubes, too. (You know, tubes filled with empty space,
| > | which you just said emission theory _is_ about.)
| >
| > Emission theory is what Einstein used to derive his cuckoo
| > transforms before he added his own definition of time. Sagnac has
| > air on the OUTSIDE, dragging the light on the inside. You are seeing
| > conservation of momentum, nothing more.
|
| Say that again? You'll need to spell that out because I didn't get
it.
Ok...
Part one:
Emission theory is what Einstein used to derive his cuckoo
transforms before he added his own definition of time.
You can see that it takes 4 seconds to travel the length of a 32 unit
cable one way and 16 seconds the other.
Part two:
A magnet doesn't have to touch a conductor to induce a current, right?
The field passes through the conductor.
Light is electromagnet in its form, and the magnetic field of the light
will interact with air outside the fibre.
| The version with evacuated tubes emits the light in vacuum, and
| reflects it off of mirrors in vacuum.
In a G-field. Near other fixed objects.
Now, you might think I'm floundering here. You'd be right, I am.
What is DO know is that relativity is stupid and there is research
needed, which isn't going to happen all the time you relativists
claim to have all the answers. I don't have all the answers, I only
know you've got the wrong one.
|
| The version with a fiber optic ring emits the light directly into the
| fiber, and the whole lot goes around together.
|
| > | > Sagnac space isn't empty.
| > |
| > | The experiment's been done both ways: empty space and non-empty
| > | space. The result is much the same: the time to go around the
| > | ring is different one way than the other way, when the ring is
| > | rotating. It's quite strange.
| >
| > You are back to a universal frame, then.
|
| That's one way to explain it. But then you run into trouble with
| MMX.
You were in trouble the moment you accepted the cuckoo transforms,
because tau(x',y,z,t) isn't tau(x,y,z,t).
Tau is a transform from the train to the train, not the track to the
train.
Androcles.
|
Sue...
Androcles wrote:
snip
> |
> | Ouch! Don't know, and can't even picture it.
>
>
> (fixed font)
> Connect the edges as shown, A to B, B to B.
>
> __________
> | open |
> | |
> | |
> open open plain plane
> | |
> | |
> |___open__|
>
>
> ___A_>_B__
> | |
> | |
> | |
> open open Moebius strip
> | |
> | |
> |__B_<_A__|
>
>
> ___A_>_B__
> | |
> c c
> | |
> v v torus
> | |
> D D
> |__A_>_B__|
>
> ___A___
> / \
> | |
> | |
> A A sphere
> | |
> | |
> \____A___/
>
>
> ___A_>_B__
> | |
> C C
> | |
> v v Klein bottle
> | |
> D D
> |__B_<_A__|
>
>
>
>
>
> You were in trouble the moment you accepted the cuckoo transforms,
> because tau(x',y,z,t) isn't tau(x,y,z,t).
> Tau is a transform from the train to the train, not the track to the
> train.
>
> Androcles.
>
>
Now if interchanging time and space only worked
as well as the appropriate application of Coulomb's
Law we could really dazzle 'em with magic tricks. ;-)
Sue...
http://scienceworld.wolfram.com/physics/CoulombsLaw.html
http://scienceworld.wolfram.com/physics/CoulombForce.html
> |
Androcles
"Sue..." <suzyse...@yahoo.com.au> wrote in message
news:1123072709.1...@g44g2000cwa.googlegroups.com...
Err... topology.
Chewing gum or modelling clay doesn't have much geometry.
You can stretch the surfaces, shrink them, bend them, puncture
them, but they have to remain surfaces.
Can you puncture a torus and turn it inside out?
Theoretically you can, you've opened an edge of
___A_>_B__
| |
c c
| |
v v torus
| |
D D
|__A_>_B__|
so its a pipe, a cylinder.
Get an old car tyre inner tube and try it.
| Now if interchanging time and space only worked
| as well as the appropriate application of Coulomb's
| Law we could really dazzle 'em with magic tricks. ;-)
|
| Sue...
| http://scienceworld.wolfram.com/physics/CoulombsLaw.html
| http://scienceworld.wolfram.com/physics/CoulombForce.html
I've told you before, you can't have mu0, epsilon0.
You can have mu1, mu2, mu3, mu(n), but no mu0.
Now be a good girl and play with the safe toys you've been
given, mu0 and epsilon0 are locked away in the cupboard
where you can't reach them, along with the speed of sound
in a vacuum and the volume of a gas at absolute zero.
Now now, stop pouting, I mean what I say. You can't have
mu0 or epsilon0 to play with, there's aether in them and its
dangerous for little girls.
Here's a black hole instead. See if you can find the bright
green flying elephant's egg at the bottom.
Androcles.