Gravity experiment / Michaelson Morley
Graeme Prentice
I don't know much about physics but I have a couple of questions.
A few weeks ago I read (on MSN website I think) about an experiment
done at a university in the U.S. to do with the speed of propagation
of gravity (I think) and the results were supposed to be available in
November but I haven't been able to find out if the result of the
experiment has been published - is this information available
anywhere?
Second question : I would like to understand the Michaelson Morley
experiment but I have the impression it's a slightly contentious issue
- is there a "mainstream" explanation for this experiment that most
people agree on and where can I find some information that explains
the result of the experiment - preferably something suitable for a
person not directly involved in physics or mathematics.
Graeme
dlzc@aol.com (formerly)
"Graeme Prentice" <g...@paradise.net.nz> wrote in message
news:en970v4v5g5sgbvsu...@4ax.com...
>
> I don't know much about physics but I have a couple of
questions.
>
> A few weeks ago I read (on MSN website I think) about an
experiment
> done at a university in the U.S. to do with the speed of
propagation
> of gravity (I think) and the results were supposed to be
available in
> November but I haven't been able to find out if the result of
the
> experiment has been published - is this information available
> anywhere?
November was expected, but not hit. I have not heard what the
next goal is, but if a University is involved, I would expect
after final exams...
> Second question : I would like to understand the Michaelson
Morley
> experiment but I have the impression it's a slightly
contentious issue
> - is there a "mainstream" explanation for this experiment that
most
> people agree on and where can I find some information that
explains
> the result of the experiment - preferably something suitable
for a
> person not directly involved in physics or mathematics.
The Michelson-Morley experiment was to detect the presence of the
aether, the expected fluid through which light propagates. This
has been done up even into the 1960s using more and more precise
methods, and no variance in c has been detected between light
travelling a path with (or against) the Earth and a path
perpendicular to the Earth.
No variation in the two travel paths was found. So either the
aether is
stuck to Terra, Terra is at the center of the "aether Universe",
the mechanism that was oriented with/against Earth's motion
changed length just enough to give an unchanged result, or light
does not require a medium to travel through.
The last is the simplest and most believable.
David A. Smith
John C. Polasek
The MM experiment ostensibly tested for the vector addition of orbital
velocity and c, computing time differences from interference fringes.
The reason they could not detect an ether or ether wind is that vector
addition does not apply, at least not linearly. The velocity of light
is always at right angles with any velocity we can come up with, and
consequently you are drawing a right angle triangle which is identical
upstream or downstream.
This is the heart of the Lorentz contraction, which is erroneously
considered to shrink the test bed in the direction of the velocity.
Nothing needs to shrink. The two "velocities" are always orthogonal.
Mr. Dual Space
(If you have something to say, write an equation.
If you have nothing to say, write an essay).
Stephen Speicher
>
> I don't know much about physics but I have a couple of questions.
>
> A few weeks ago I read (on MSN website I think) about an experiment
> done at a university in the U.S. to do with the speed of propagation
> of gravity (I think) and the results were supposed to be available in
> November but I haven't been able to find out if the result of the
> experiment has been published - is this information available
> anywhere?
>
The mid-November date was just an estimate. There is a lot of
data to be processed, and care must be taken to get it all right.
It may still be some time before the final results are released,
but, hopefully, there should be some announcement fairly soon.
> Second question : I would like to understand the Michaelson Morley
> experiment but I have the impression it's a slightly contentious issue
The Michelson-Morley experiment is a rather straightforward one,
and any contention is only by a few somewhat ignorant
anti-relativists who post here.
> - is there a "mainstream" explanation for this experiment that most
> people agree on and where can I find some information that explains
> the result of the experiment - preferably something suitable for a
> person not directly involved in physics or mathematics.
>
The experiment is discussed in many elementary texts on
relativity, and a search on google.com for "Michelson-Morley
experiment" reveals more than 6100 hits. I personally do not
rely on the veracity of internet sites for research I do, but in
general you can feel more comfortable with sites which are
lectures for university courses. I also notice the third site
listed was for Eric Weisstein's "World of Physics" site at
Wolfram Research. I have not read this particular one, but in
general I have found Weisstein's web pages to be pretty reliable
information, reflecting the "mainstream" explanations, as you
asked for.
http://scienceworld.wolfram.com/physics/Michelson-MorleyExperiment.html
--
Stephen
s...@speicher.com
Ignorance is just a placeholder for knowledge.
Printed using 100% recycled electrons.
-----------------------------------------------------------
Dirk Van de moortel
"John C. Polasek" <jpol...@cfl.rr.com> wrote in message news:3e03e713.4740981@news-server...
Welcome to
http://users.pandora.be/vdmoortel/dirk/Physics/ImmortalFumbles.html#Heart
Title: "MMX, right angles and the heart"
>
> Mr. Dual Space
> (If you have something to say, write an equation.
> If you have nothing to say, write an essay).
Quite appropriate :-)
Dirk Vdm
ca314159
>
> Second question : I would like to understand the Michaelson Morley
> experiment but I have the impression it's a slightly contentious issue
> - is there a "mainstream" explanation for this experiment that most
> people agree on and where can I find some information that explains
> the result of the experiment - preferably something suitable for a
> person not directly involved in physics or mathematics.
>
It was a kind of interferometer.
Interferometers can measure many things at the same time:
a. relative difference in the lengths of it's arms
b. difference in the relative refractive indices of the media in the arms
c. the thickness of a refractive media sample placed in one of its arms
d. coherence length of the light source
... etc.
Which of the above was the M-M experiment trying to measure ?
Michelson Morley's original paper:
http://spiff.rit.edu/classes/phys314/refs/mm.html
Stephen Speicher
>
> "John C. Polasek" <jpol...@cfl.rr.com> wrote in message news:3e03e713.4740981@news-server...
> >
> > considered to shrink the test bed in the direction of the velocity.
> > Nothing needs to shrink. The two "velocities" are always orthogonal.
>
> Welcome to
> http://users.pandora.be/vdmoortel/dirk/Physics/ImmortalFumbles.html#Heart
> Title: "MMX, right angles and the heart"
>
I'm surprised it took this long for his inclusion. Polasek is a
real loony. The stamp of the "Supreme Being," "Creation," and
"God" are all over his own "Ether" monstrosity, with gravity as a
"natural result of the Creation process."
> >
> > Mr. Dual Space
According to "Mr. Dual Space," aka Mr. Loony Tunes, the "Supreme
Being" created "Mspace" and "Espace," with the "two worlds
working together."
> > (If you have something to say, write an equation.
> > If you have nothing to say, write an essay).
>
> Quite appropriate :-)
>
Indeed!
Abhi
>
> A few weeks ago I read (on MSN website I think) about an experiment
> done at a university in the U.S. to do with the speed of propagation
> of gravity (I think) and the results were supposed to be available in
> November but I haven't been able to find out if the result of the
> experiment has been published - is this information available
> anywhere?
Dr. Kopeikin, who lead the team of scientists who carried out this
speed of gravity experiment, is die-hard Einsteinian. I am sure, his
computer is telling him that gravitational field of jupiter is
changing with I-speed (instantaneous / infinite speed) everywhere as
jupiter changes its position. He is just making sure that somewhere he
is not making any mistake.
And there is no mistake. What we call gravity, is "density of nothing
i.e. space, vacuum". Without this density of nothing, big-bang could
never happen.
-Abhi.
Abhi
> Dear "Graeme Prentice":
> "Graeme Prentice" <g...@paradise.net.nz> wrote in message
> news:en970v4v5g5sgbvsu...@4ax.com...
> >
> > I don't know much about physics but I have a couple of
> questions.
> >
> > A few weeks ago I read (on MSN website I think) about an
> experiment
> > done at a university in the U.S. to do with the speed of
> propagation
> > of gravity (I think) and the results were supposed to be
> available in
> > November but I haven't been able to find out if the result of
> the
> > experiment has been published - is this information available
> > anywhere?
>
> November was expected, but not hit. I have not heard what the
> next goal is, but if a University is involved, I would expect
> after final exams...
>
This will not be acceptable to anyone if they withheld such important
result for just conclusion of university exams.
-Abhi.
Dirk Van de moortel
"Abhi" <discov...@yahoo.co.in> wrote in message news:4bd62e7c.02122...@posting.google.com...
> Graeme Prentice <g...@paradise.net.nz> wrote in message news:<en970v4v5g5sgbvsu...@4ax.com>...
> > I don't know much about physics but I have a couple of questions.
> >
> > A few weeks ago I read (on MSN website I think) about an experiment
> > done at a university in the U.S. to do with the speed of propagation
> > of gravity (I think) and the results were supposed to be available in
> > November but I haven't been able to find out if the result of the
> > experiment has been published - is this information available
> > anywhere?
>
> Dr. Kopeikin, who lead the team of scientists who carried out this
> speed of gravity experiment, is die-hard Einsteinian. I am sure, his
> computer is telling him that gravitational field of jupiter is
> changing with I-speed (instantaneous / infinite speed) everywhere as
> jupiter changes its position. He is just making sure that somewhere he
> is not making any mistake.
Sounds like you feel you're going to lose a bet.
Sounds like you are a poor loser.
Dirk Vdm
John C. Polasek
I believe it's worth repeating, something so simple, no one has ever
thought of it, or if they had, to be laughed to scorn by the high
priests in this NG.
"Velocity of light is orthogonal to any physical velocity.
The velocity of light is no ordinary velocity".
Have you ever seen the expression x + y + z - ict? (1)
There's no such thing. That would imply absolute position.
But how about xdot + ydot + zdot - ic? (2)
That little i in the equation makes ic orthogonal to any velocity
vector you can name. It is just one proof that c is orthogonal to any
physical velocity. That expression for velocity will remain unchanged
going upstream or downstream. The MM experiment is a total bust.
Drawing on all your blinding brilliance, tell me how you would work
with equation 2 to prove any;thing about ether drift. The experiment
was doomed from the start based on simple principles of relativity. No
stretching of the apparatus is required either.
I'll also invite you to write an equation.
Ken Seto
The MMX null result can be explained as follows:
The MMX apparatus is moving in the vertical direction.
All the light rays generated is moving horizontally. This
means that the light path length from both arms of the MMX
apparatus will remain constant in all the horizontal
orientations of the arms and thus the MMX null result.
Ken Seto
This means that
dlzc@aol.com (formerly)
"Abhi" <discov...@yahoo.co.in> wrote in message
news:4bd62e7c.02122...@posting.google.com...
If you were taking classes, and needed to study for the exams,
you would be less likely to work on a huge project of data
reduction.
If you were an instructor, you would similarly be spending time
making up tests that are considered to be the equivalent of
thumbscrews.
Be patient. Consider it a gift to be able to continue posting.
David A. Smith
student
>
>A few weeks ago I read (on MSN website I think) about an experiment
>done at a university in the U.S. to do with the speed of propagation
>of gravity (I think) and the results were supposed to be available in
>November but I haven't been able to find out if the result of the
>experiment has been published - is this information available
>anywhere?
They'll publish when they feel their results are ready for publication.
Expect no less from responsible researchers...
of course this is usenet; if anybody has rumors, then we're all ears...
>
>Second question : I would like to understand the Michaelson Morley
>experiment but I have the impression it's a slightly contentious issue
Not the least bit contentious, except among a few loonies...
>- is there a "mainstream" explanation for this experiment that most
>people agree on and where can I find some information that explains
>the result of the experiment - preferably something suitable for a
>person not directly involved in physics or mathematics.
With apologies for the lack of physics content, I'll leave that up
to someone with more expertise to answer
>
>Graeme
Graeme Prentice
Thanks to everyone who answered. I have not found any information on
the web that explains this experiment to my satisfaction, so I have
speculated as below, and am hoping that someone can tell me if
anything I have written is wrong and why it is wrong. I have come to
the conclusion that a "cancelling effect" is the reason the two light
paths are the same distance even though the earth (and the mirrors)
are moving relative to the light ray. If it sounds like I know a
small amount of physics, I don't really, although I did do a first
year course at university a long time ago.
On 21 Dec 2002 15:52:37 -0800, ken...@erinet.com (Ken Seto) wrote:
>
>The MMX null result can be explained as follows:
>The MMX apparatus is moving in the vertical direction.
>All the light rays generated is moving horizontally. This
>means that the light path length from both arms of the MMX
>apparatus will remain constant in all the horizontal
>orientations of the arms and thus the MMX null result.
>
I don't understand this comment (unless its a simplification). It
seems to me that the line of the earth's rotation around the sun can
be at any angle at all, relative to the plane of the MM apparatus
depending on whereabouts on the surface of the earth the apparatus
happens to be and also what its angle of inclination to the surface of
the earth is e.g. suppose the "North pole" is the "leading point" of
the earth's movement (i.e. the line of the earth's movement is
directly from the south pole to the north pole) and the apparatus is
at the north pole, then the line of the earth's movement is at 90
degrees to the plane of the apparatus. Six hours later (or 18 ?), the
earth has rotated and the apparatus is now at the closest point to the
sun, directly facing the sun, and the line of the earth's motion is
now parallel to the plane of the apparatus.
Rotating the apparatus (as Michelson did) has no effect on the angle
between the line of the earth's movement and the plane of the
apparatus, unless it alters the angle of inclination between the plane
of the apparatus and the surface of the earth - but rotation of the
apparatus does alter the component of the velocity of the mirrors in
the direction of the light ray.
If the apparatus actually is at the real north pole, then the angle
between the line of the earth's rotation round the sun and the plane
of the apparatus will not change much in 24 hours, compared to other
points on the surface of the earth.
Until now, I had the impression (I think from encarta encylopaedia)
the the length contraction idea was the explanation for the null
result, and did not realise the explanation was that the distances
travelled by the two light rays was identical.
I have tried to work out what these distances are and found it hard
and came to the conclusion that the only reason the two light paths
can be the same distance is
1. The length of the two light paths is identical when the apparatus
is at absolute rest
2. There is an exactly equal cancelling effect as the light ray goes
back and forth across the MM apparatus - the distance the light ray
goes in the "outward" direction is further (due to the motion of the
earth) than when at absolute rest, but is compensated for by the
return journey being a shorter distance by the exact same amount.
I am not sure that an "exact cancelling" occurs. Is this what happens
or am I totally off the track here?
A diagram of the apparatus is shown here
http://electricnature.net/mm.htm
it is the same diagram as in the 1887 document written by MM but this
web page loads much faster than the web page with the original
document someone else posted the link to (thanks).
http://spiff.rit.edu/classes/phys314/refs/mm.html
You can see that each of the two light rays crosses the apparatus
multiple times before arriving at the interferometer ( f ) in the
bottom right corner. I am curious to know if it is actually
technically possible to make the two light paths equal distances
because that seems to me quite hard to achieve.
Actually, even if the light paths were different distances when at
absolute rest, the cancelling effect would mean that any phase
difference seen (interference fringes?) would be unchanging no matter
what the orientation of the apparatus is.
More detail on the cancelling effect
--------------------------------------------------
I am not sure that it is clear what I mean by the cancelling effect so
I will try to explain it with a diagram.
First of all, I tried to calculate how far the mirror moves between
the time the light photon leaves the light source and the time it
arrives at the mirror - if the distance is 1 meter and the mirror is
moving away at 30000 meters per second (earth's rotation speed) then
the mirror moves approx 1.000692 times 10 to the power of minus 4 -
which is approx 196 "wavelengths of light" (I found somewhere the
wavelength of light is approx one fifty thousandth of an inch.)
Referring to the diagram in the MM document I have tried to redraw it
here. From looking at the original diagram, there are actually four
mirrors at each of the four corners of the apparatus (16 mirrors
altogether)
d- d
b
e e-
a f
The original light source is at a - the interferometer is at f - the
beam splitter is in the center at b.
Light path one is a b d e d e d e d e then it retraces itself
d e d e d e d b f (is that right?)
Light path two is a b d- e- etc similar to path one before arriving
back at b then f.
For light path one, because the light retraces its path, the
cancelling effect will be exact because at absolute rest, the light
spends an identical amount of time going in the d to e direction as it
does going in the e to d direction. Same with path two.
Does the light retrace its path - if so, how can it do that without
colliding with itself?
It seems to me the cancelling effect should be exact whatever the
orientation of the plane of the apparatus to the line of the earth's
motion through the universe except for the fact that the orientation
changes slightly all the time but presumably this has only a very
small effect or maybe none at all?
Is this correct or am I way off the track?
Thanks to anyone who reads this.
Graeme
Graeme Prentice
wrote:
>
> It was a kind of interferometer.
>
> Interferometers can measure many things at the same time:
>
> a. relative difference in the lengths of it's arms
> b. difference in the relative refractive indices of the media in the arms
> c. the thickness of a refractive media sample placed in one of its arms
> d. coherence length of the light source
> ... etc.
>
> Which of the above was the M-M experiment trying to measure ?
None of the above (except I don't know what coherence is), - it was
trying to get some evidence for the existence of ether and its motion
relative to the earth ( I read this somewhere). I don't know why
they thought the ether was moving - if the ether wasn't moving then
their experiment wouldn't show anything, so they thought.
Graeme
Abhi
No way. Day by day my confidence is increasing. If speed of gravity
had been equal to speed of light, Dr. Kopeikin would not have given
second thought and result would have been declared one-two month ago.
But he is taking time. That means he is checking his paper, equations,
computer software etc. again and again. He is die-hard Einstenian.
But today or tommorrow, he will have to declare I-speed of gravity.
And one more thing. Perhaps experimental idea in my mind is taking
final shape. I would not have found "pure math" if my theory had been
wrong.
I am ready to make same agreement with you or any one which I made
with Stephen.
Is somebody coming forward?
Don't be afraid. If I lose, I lose alone.
But in totality, if I win, everybody wins. Nobody loses.
-Abhi.
Joe Fischer
: No way.
Of course not, you are infallible.
: Day by day my confidence is increasing.
It must be the good diet.
: If speed of gravity
: had been equal to speed of light, Dr. Kopeikin would not have given
: second thought and result would have been declared one-two month ago.
Gravity does not have a speed, supposedly gravitational
radiation propagates at c, but that is not the mechanism of
gravitation,
: But he is taking time. That means he is checking his paper, equations,
: computer software etc. again and again. He is die-hard Einstenian.
Or maybe a capable dedicated scientist.
: But today or tommorrow, he will have to declare I-speed of gravity.
Of course, gravity acts as if it were instantaneous,
because it doesn't act at a distance, it acts locally to the
source.
The problem is, not everybody has the same ideas
about "space", even though SR needs Euclidean space,
and SR works flawlessly, there is no Euclidean space
and space has no attributes.
: And one more thing. Perhaps experimental idea in my mind is taking
: final shape.
Oh, good, the world is saved.
: I would not have found "pure math" if my theory had been
: wrong.
All math that is correct is "pure", you haven't
found anything but the size of you ego.
: I am ready to make same agreement with you or any one which I made
: with Stephen.
Stephen who, Hawking?
: Is somebody coming forward?
:
: Don't be afraid. If I lose, I lose alone.
: But in totality, if I win, everybody wins. Nobody loses.
And if everybody wins, you win, you are not alone.
Joe Fischer
--
3
Joe Fischer
: On 21 Dec 2002 15:52:37 -0800, ken...@erinet.com (Ken Seto) wrote:
:>The MMX null result can be explained as follows:
:>The MMX apparatus is moving in the vertical direction.
:>All the light rays generated is moving horizontally. This
:>means that the light path length from both arms of the MMX
:>apparatus will remain constant in all the horizontal
:>orientations of the arms and thus the MMX null result.
:
: I don't understand this comment (unless its a simplification).
No, it is nonsense written by an aetherist.
: It seems to me that the line of the earth's rotation around the sun can
: be at any angle at all, relative to the plane of the MM apparatus
: depending on whereabouts on the surface of the earth the apparatus
: happens to be
:[snip]
: Is this correct or am I way off the track?
Since this is the relativity newsgroup, ask
Ken Seto in the aether newsgroup about aether, you
will be able to get more confused than you know.
Joe Fischer
--
3
Martin Hogbin
"Graeme Prentice" <g...@paradise.net.nz> wrote in message news:qc3b0vcl1d8jmvffp...@4ax.com...
As you will see from many of the replies that you have received, there
are many crackpots on this group who will not give you the
'mainstream' answer that you asked for. For that reason it is well worth
looking at the links that Stephen Speicher suggested.
Now for an answer to your question. At the end of the 19th century,
Maxwell came up with a famous set of equations that gave the speed
of electromagnetic waves. This speed was the same as that which had
been measured for light and it was therefore assumed (correctly) that
light was a form of electromagnetic wave.
One feature of Maxwell's equations is that they did not include any
terms which relate to the velocity of the source of the waves, in other
words they imply that light from a source that is stationary with respect
to you and light from a source travelling towards you would be measured
by you to travel at the same speed.
This was not a serious problem for physicists of the day who assumed
that light would travel at a fixed speed relative to the medium (the aether)
through which it was assumed to propagate. Just like sound in air.
This presumed aether was indeed a strange substance in that it had to allow
bodies to pass freely through it but be able to carry a transverse wave
at enormous speed. It was also considered, in the light of experimental
evidence, that the aether would have to be 'rigid' like a solid rather than
fluid like a gas or liquid. In other words, the aether represented a
reference frame relative to which all velocities could be measured.
Note that this was a departure from previous thinking, typified by that of
Galileo, that all motion was relative.
Michelson and Morley duly set out to measure the motion of the Earth
through the aether. They argued that the Earth, in its orbit round the sun,
must be travelling through the aether and, as light moves at a fixed
speed with respect to the aether, the velocity on light Earth would be
different in different directions depending on how the measured
direction related to the Earth's motion through the aether. This is
like measuring the speed of sound on the back of a moving truck
parallel and perpendicularly to the direction of motion. You would
expect to get different answers.
Briefly, MM used an interferometer to compare the speed of light
in two perpendicular directions. They found no difference, which
was a great puzzle for physicists of the day. Enter Einstein...
Martin Hogbin
Abhi
Umnn.....
You must anticipate problems before you begin big projects.
-Abhi.
Abhi
I am not going to lose. No way. No way, no, no, no. No^(infinity)
>
> : Day by day my confidence is increasing.
>
> It must be the good diet.
Umnn.. I am anticipating at least two weeks of deadly migrain attacks
after gap of eight months. But doesn't matter. I am in good spirit.
>
> : If speed of gravity
> : had been equal to speed of light, Dr. Kopeikin would not have given
> : second thought and result would have been declared one-two month ago.
>
> Gravity does not have a speed, supposedly gravitational
> radiation propagates at c, but that is not the mechanism of
> gravitation,
No confusion. If I move apple on earth, how long will it take for a
star in distant galaxy to know about the displacement of apple?
>
> : But he is taking time. That means he is checking his paper, equations,
> : computer software etc. again and again. He is die-hard Einstenian.
>
> Or maybe a capable dedicated scientist.
I don't doubt that.
>
> : But today or tommorrow, he will have to declare I-speed of gravity.
>
> Of course, gravity acts as if it were instantaneous,
> because it doesn't act at a distance, it acts locally to the
> source.
> The problem is, not everybody has the same ideas
> about "space", even though SR needs Euclidean space,
> and SR works flawlessly, there is no Euclidean space
> and space has no attributes.
>
Change the idea of static space. Think about moving space with matter
in time dimension.
> : And one more thing. Perhaps experimental idea in my mind is taking
> : final shape.
>
> Oh, good, the world is saved.
It had been , will be destroyed and created infinite times. I will
have to write this reply to your post infinite times, in infinite
possible ways. Damn it.
>
> : I would not have found "pure math" if my theory had been
> : wrong.
>
> All math that is correct is "pure", you haven't
> found anything but the size of you ego.
>
I will explain later on what I mean by "pure math".
So far ego is concerned, for every "ego", there is equal and opposite
"ego"(!). So my ego is just reaction of your ego.
> : I am ready to make same agreement with you or any one which I made
> : with Stephen.
>
> Stephen who, Hawking?
Stephen Speicher, "Brief History of Relativity".
>
> : Is somebody coming forward?
> :
> : Don't be afraid. If I lose, I lose alone.
> : But in totality, if I win, everybody wins. Nobody loses.
>
> And if everybody wins, you win, you are not alone.
>
> Joe Fischer
For me, victory means better understanding of God and Universe. If
anybody answer my questions which you call "philosophy", then it is my
victory.
If somebody do not answer, I will try to answer myself.
-Abhi.
Dirk Van de moortel
> > Abhi <discov...@yahoo.co.in> wrote:
> > : No way.
> >
> > Of course not, you are infallible.
>
> I am not going to lose. No way. No way, no, no, no. No^(infinity)
Which implies that you will never admit that you were wrong.
Never, never, never, never. Never^(infinity).
Dirk Vdm
Graeme Prentice
<sp...@hogbin.org> wrote:
>
>"Graeme Prentice" <g...@paradise.net.nz> wrote in message news:qc3b0vcl1d8jmvffp...@4ax.com...
>> On Sat, 21 Dec 2002 09:02:03 -0500, ca314159 <ca31...@bestweb.net>
>> wrote:
>>
>>
>> > Which of the above was the M-M experiment trying to measure ?
>>
>> None of the above (except I don't know what coherence is), - it was
>> trying to get some evidence for the existence of ether and its motion
>> relative to the earth ( I read this somewhere). I don't know why
>> they thought the ether was moving - if the ether wasn't moving then
>> their experiment wouldn't show anything, so they thought.
>
>As you will see from many of the replies that you have received, there
>are many crackpots on this group who will not give you the
>'mainstream' answer that you asked for. For that reason it is well worth
>looking at the links that Stephen Speicher suggested.
Yes I did look at the link he posted but it didn't give any of the
detail I wanted about why the two light path lengths on the MM device
were the same.
Thanks for the explanation about the MM experiment. I have to admit I
was confused about whether it made any difference if the supposed
aether was moving or not but didn't think very hard about it because
we know that any such aether is not the medium of light wave
transmission.
In my other long post I tried to explain why I thought the light path
lengths are the same, even though the mirrors involved are moving at
different speeds relative to the light beam i.e. the mirrors in light
path one are moving at different speeds (relative to the light beam)
than the mirrors in light path two are. I decided that this
difference in speed cancels itself out - do you have any idea if this
is the case.
I think it would be possible to arrange the mirrors on the MM device
so that the *difference* between the two light path lengths could be
made different when the device is moving compared to when the device
is at absolute rest - and similarly, the light path lengths could be
made to change by different amounts as the device is rotated (I
think).
Graeme
Ken Seto
> Thanks to everyone who answered. I have not found any information on
> the web that explains this experiment to my satisfaction, so I have
> speculated as below, and am hoping that someone can tell me if
> anything I have written is wrong and why it is wrong. I have come to
> the conclusion that a "cancelling effect" is the reason the two light
> paths are the same distance even though the earth (and the mirrors)
> are moving relative to the light ray. If it sounds like I know a
> small amount of physics, I don't really, although I did do a first
> year course at university a long time ago.
>
>
> On 21 Dec 2002 15:52:37 -0800, ken...@erinet.com (Ken Seto) wrote:
>
> >
> >The MMX null result can be explained as follows:
> >The MMX apparatus is moving in the vertical direction.
> >All the light rays generated is moving horizontally. This
> >means that the light path length from both arms of the MMX
> >apparatus will remain constant in all the horizontal
> >orientations of the arms and thus the MMX null result.
> >
>
> I don't understand this comment (unless its a simplification).
Ity is a simplification.
> It seems to me that the line of the earth's rotation around the sun can
> be at any angle at all, relative to the plane of the MM apparatus
> depending on whereabouts on the surface of the earth the apparatus
> happens to be and also what its angle of inclination to the surface of
> the earth is e.g. suppose the "North pole" is the "leading point" of
> the earth's movement (i.e. the line of the earth's movement is
> directly from the south pole to the north pole) and the apparatus is
> at the north pole, then the line of the earth's movement is at 90
> degrees to the plane of the apparatus. Six hours later (or 18 ?), the
> earth has rotated and the apparatus is now at the closest point to the
> sun, directly facing the sun, and the line of the earth's motion is
> now parallel to the plane of the apparatus.
NO...you are mixing observed relative motion with absolute
motion. The MMX apparatus can have an infinite number of
relative motions but it can only have one state of absolute
motion (motion relative to light). So what is the direction
of this absolute motion of the MMX apparatus? The answer to this
question is: the vertical direction. Why?? Beacuase that's
the only direction of absolute motion will give the same
light path length for all the horizontal orientations of
the arms of the MMX apparatus.
YOu can visualize the null result as follows:
1. The MMX apparatus is moving in the vertical direction.
2. Therefore, the mirrors at the ends of the arms, acting as
light sources, are also moving in the vertical direction.
3. The center mirror that re-combines the light rays from the
mirrors are also moving in the vertical direction.
4. The light path length..from the mirrors at the ends of the
arms to the re-combining mirror..will remain the same for all
the horizontal orientations of the arms (mirrors)and thus the
null result.
Ken Seto
dlzc@aol.com (formerly)
"Abhi" <discov...@yahoo.co.in> wrote in message
news:4bd62e7c.02122...@posting.google.com...
...
> Umnn.....
>
> You must anticipate problems before you begin big projects.
I thought it was a mistake to attempt analysis in under two
months. I thought it another mistake to attempt to pull it off
before finals. But I am an idiot, and no one asked me what a
reasonable deadline might be. ;>}
I consider the November deadline to be the salesman's attempt at
keeping the customer happy. February sounds much better to me.
To reach out and grab a month...
David A. Smith
Martin Hogbin
"Graeme Prentice" <g...@paradise.net.nz> wrote in message news:7u9c0vgvnfiu0m9rm...@4ax.com...
> On Sun, 22 Dec 2002 12:05:45 +0000 (UTC), "Martin Hogbin"
> <sp...@hogbin.org> wrote:
>
> Thanks for the explanation about the MM experiment. I have to admit I
> was confused about whether it made any difference if the supposed
> aether was moving or not but didn't think very hard about it because
> we know that any such aether is not the medium of light wave
> transmission.
>
> In my other long post I tried to explain why I thought the light path
> lengths are the same, even though the mirrors involved are moving at
> different speeds relative to the light beam i.e. the mirrors in light
> path one are moving at different speeds (relative to the light beam)
> than the mirrors in light path two are. I decided that this
> difference in speed cancels itself out - do you have any idea if this
> is the case.
There is a difference between the 'parallel' and the 'perpendicular'
paths which depends on V^2 / c^2, where V is the speed through
the aether.
> I think it would be possible to arrange the mirrors on the MM device
> so that the *difference* between the two light path lengths could be
> made different when the device is moving compared to when the device
> is at absolute rest - and similarly, the light path lengths could be
> made to change by different amounts as the device is rotated (I
> think).
This is preceisely what M and M did.
Martin Hogbin
Joe Fischer
: Joe Fischer <grav...@shell1.iglou.com> wrote:
:> Gravity does not have a speed, supposedly gravitational
:> radiation propagates at c, but that is not the mechanism of
:> gravitation,
:
: No confusion. If I move apple on earth, how long will it take for a
: star in distant galaxy to know about the displacement of apple?
This statement shouts out how stupid your
impression of the mechanism of gravitation is.
And does the apple know when distant stars collide?
There is no communication between source and
target, it is obvious in General Relativity that there
is nothing propagated for the apparent change in motion
due to gravity, in fact, it is obvious the change in
motion is only apparent.
Study inertial motion, and forget about
Euclidean space and mystical attractions at great
distances.
Joe Fischer
--
3
Graeme Prentice
I'm lost. I know they rotated the device and they also shifted its
location to a mountain top but neither of these things produced any
change in the interference fringes - meaning the light path lengths
changed by the same amount or did not change at all.
Do you know if there's any book that explains this experiment in full
detail?
Graeme
dlzc@aol.com (formerly)
"Graeme Prentice" <g...@paradise.net.nz> wrote in message
news:dqjc0v0vcpcpbssa8...@4ax.com...
http://astro.ocis.temple.edu/~meziani/michelson.pdf
lab on how to perform the experiment yourself.
http://www.upei.ca/~phys221/nem/Apparatus/apparatus.html
pictures of the original apparatus, and how it is expected to
work
(the "Experiment" button links to some of the expectations)
http://www.wikipedia.org/wiki/Interferometer
definition of an interferometer
http://www.wikipedia.org/wiki/Michelson-Morley_experiment
a brief bit on the experiment itself.
http://galileoandeinstein.physics.virginia.edu/lectures/michelson
.html
a link that pretty much ties it all together.
not a book though... since it has been refined and improved upon.
David A. Smith
Ken Seto
Joe Fisher is a moron and a runt of the SR experts.
Ken Seto
Stephen Speicher
> On Sun, 22 Dec 2002 23:10:05 +0000 (UTC), "Martin Hogbin"
> <sp...@hogbin.org> wrote:
>
> >
> >This is preceisely what M and M did.
> >
>
> I'm lost. I know they rotated the device and they also shifted its
> location to a mountain top
I think you are confused. The 1887 Michelson-Morley experiment
was performed in the basement of Adelbert Hall, Western Reserve
University, in Cleveland, Ohio. Perhaps you are thinking of some
much later experiments.
>
> Do you know if there's any book that explains this experiment in full
> detail?
>
As I mentioned previously, most any introductory text on
relativity will have an explanation of the Michelson-Morley
experiment. If you want a couple of very inexpensive paperback
references: Max Born, "Einstein's Theory of Relativity," _Dover_,
1924/1962, or Peter Gabriel Bergmann, "Introduction to the Theory
of Relativity," _Dover_, 1942/1976. Both of these books are very
inexpensive, and each devote a number of pages to a description
and analysis of the experiment.
But, why not read the Michelson-Morley paper yourself,
first-hand. Someone posted an online pointer to the original
paper, and the paper is written in plain enough terms as to be
understandable by most anyone. They outline the experimental
setup in detail, they show the relatively simple mathematics
involved, they provide the experimental results, and then present
their conclusion. Read the paper, and judge for yourself.
Hayek
Graeme Prentice wrote:
> - is there a "mainstream" explanation for this experiment that most
If you want "mainstream" :
When interviewed more than 50% of us-citizens believed
that the bible is true, word for word....
All of these theories have been "mainstream" :
- Flat Earth
- Earth in the middle of the universe.
- Flogiston
...
In fact I will Yank Uncle All again by claiming that
science does not exist, it is a cycle of dogma and
paradigm shifts.
So, always wear clean underwear, because you never know
when the next paradigm shift is going to hit you.
The purpose of my lecture is that you should not ask for
"mainstream". You should ask for what the possible
explanations are.
You can start doubting the setup of the experiment, for
starters. Some claim the setup is flawed.
Hayek.
--
The small particles wave at
the big stars and get noticed.
:-)
Graeme Prentice
<s...@speicher.com> wrote:
>On Mon, 23 Dec 2002, Graeme Prentice wrote:
[snip]
>
>> I'm lost. I know they rotated the device and they also shifted its
>> location to a mountain top
>
>I think you are confused. The 1887 Michelson-Morley experiment
>was performed in the basement of Adelbert Hall, Western Reserve
>University, in Cleveland, Ohio. Perhaps you are thinking of some
>much later experiments.
It says in this article that Michelson redid the experiment on top of
a mountain in California because he wondered if the aether was somehow
getting stuck to the earth.
http://galileoandeinstein.physics.virginia.edu/lectures/michelson.html
The article from 1887 also makes mention of a "mountain peak" (on page
341) as being a possible location for a future experiment.
>
>>
>> Do you know if there's any book that explains this experiment in full
>> detail?
>>
>
>As I mentioned previously, most any introductory text on
>relativity will have an explanation of the Michelson-Morley
>experiment. If you want a couple of very inexpensive paperback
>references: Max Born, "Einstein's Theory of Relativity," _Dover_,
>1924/1962, or Peter Gabriel Bergmann, "Introduction to the Theory
>of Relativity," _Dover_, 1942/1976. Both of these books are very
>inexpensive, and each devote a number of pages to a description
>and analysis of the experiment.
Thanks for those titles. I will see what I can find in my local
library tomorrow.
>
>But, why not read the Michelson-Morley paper yourself,
>first-hand. Someone posted an online pointer to the original
>paper, and the paper is written in plain enough terms as to be
>understandable by most anyone. They outline the experimental
>setup in detail, they show the relatively simple mathematics
>involved, they provide the experimental results, and then present
>their conclusion. Read the paper, and judge for yourself.
My problem with that document and some of the web articles is that the
formulas seem to be based on the existence of the ether, and also we
know more now than they did in 1887 so I don't know what is "fact" and
what is "ether based" speculation. However, I understand the diagram
better now - I got lost by the description of the light path as
bdedbf which I interpreted to mean the light crossed the apparatus 4
times but now I see it means it crosses 16 times in total and does
retrace its path as I suspected.
Could you answer a question for me - does light reflect off a moving
mirror at a different angle than off a "stationary" mirror?
The 1887 document talks about "aberration" and "special laws of
reflection" (top of page 342) and seems to indicate that if light hits
a moving mirror the light is reflected at a different angle than if
the mirror is stationary - the very first diagram in the 1887
document appears to show this on page 335 where the light path is " a
b a-dash " if the apparatus is moving
instead of " a b a "
Without knowing about this aberration I would have expected that
firing a light beam at a mirror at exactly 45 degrees it would bounce
off at exactly 45 degrees regardless of whether the mirror or light
source were at absolute rest or not.
Graeme
Graeme Prentice
wrote:
>Graeme Prentice wrote:
>
>> - is there a "mainstream" explanation for this experiment that most
>
>If you want "mainstream" :
>When interviewed more than 50% of us-citizens believed
>that the bible is true, word for word....
hehe - but less than one percent have any facts to base their "belief"
on -
I don't have beliefs, I have yes / no / probably / maybe / unknown ...
[snip]
>The purpose of my lecture is that you should not ask for
> "mainstream". You should ask for what the possible
>explanations are.
well I wanted the mainstream explanation first (i.e. as taught in the
majority of universities) and I think everyone understood that - I
wanted to see if the mainstream explanation made sense to me.
>
>You can start doubting the setup of the experiment, for
>starters. Some claim the setup is flawed.
I doubt that I'm going to be able to understand how they were able to
make the lengths of the two light paths the same - I know they could
move one mirror very small distances and they used white light, then
sodium light, then white light or something - but its gobbledegook
at this stage.
Graeme
Martin Hogbin
"Graeme Prentice" <g...@paradise.net.nz> wrote in message news:73kd0vopmcsaljng6...@4ax.com...
> My problem with that document and some of the web articles is that the
> formulas seem to be based on the existence of the ether, and also we
> know more now than they did in 1887 so I don't know what is "fact" and
> what is "ether based" speculation.
Bear in mind that the (1987) MMX was designed to test the
hypothesis that the Earth was moving through a 'rigid' aether.
In order to do this you see what predictions the hypothesis makes
and then compare them with experiment. In other words, when
analysing the MMX, you should do it according to the aether theory
that was being tested.
The MMX can be analysed using special relativity (SR). This is
particularly simple but not relevant to the purpose of the original
experiment.
> However, I understand the diagram
> better now - I got lost by the description of the light path as
> bdedbf which I interpreted to mean the light crossed the apparatus 4
> times but now I see it means it crosses 16 times in total and does
> retrace its path as I suspected.
>
> Could you answer a question for me - does light reflect off a moving
> mirror at a different angle than off a "stationary" mirror?
Yes, according to the aether theory that was being tested. Think
in terms of sound waves in air.
> The 1887 document talks about "aberration" and "special laws of
> reflection" (top of page 342) and seems to indicate that if light hits
> a moving mirror the light is reflected at a different angle than if
> the mirror is stationary - the very first diagram in the 1887
> document appears to show this on page 335 where the light path is " a
> b a-dash " if the apparatus is moving
> instead of " a b a "
>
> Without knowing about this aberration I would have expected that
> firing a light beam at a mirror at exactly 45 degrees it would bounce
> off at exactly 45 degrees regardless of whether the mirror or light
> source were at absolute rest or not.
According to SR you are quite right since the term 'absolute rest'
has no meaning in SR, but remember it was the aether theory that was
under test.
Martin Hogbin
Dirk Van de moortel
"Ken Seto" <ken...@erinet.com> wrote in message news:75dd81d3.02122...@posting.google.com...
Congratulations Joe, you finally made it!
http://groups.google.com/groups?&q=author%3Aseto+runt+fisher
welcome to
http://groups.google.com/groups?&q=author%3Aseto+runt
Dirk Vdm
>
> Ken Seto
Martin Hogbin
"Graeme Prentice" <g...@paradise.net.nz> wrote in message news:dqjc0v0vcpcpbssa8...@4ax.com...
>
> I'm lost. I know they rotated the device and they also shifted its
> location to a mountain top but neither of these things produced any
> change in the interference fringes - meaning the light path lengths
> changed by the same amount or did not change at all.
I believe the idea of moving the experiment to a mountain top was
to check out the possibility that the aether was being dragged along
with the Earth.
Such a theory would have been a nightmare, and there was
probably sufficient astronomical evidence to rule it out anyway,
but I guess M and M thought they had better make sure.
It is the 1887 experiment that is regarded as a turning point
in physics, later experiments by M and M and by others can
be regarded as closing loopholes.
Martin Hogbin
John C. Polasek
I have started a new thread "Re: Gravity experiment/Michelson Morley"
in which I more carefully analyzed the source of the null MM effect.
We all agree that the sidewise path length is on a hypotenuse by
virtue of the apparatus "skidding forward' while in transit. (An
increase of 1 unit, say). This is standard fare.
On the updown path we calculate an increase of two units, due to the
summing of inverses of velocity, and using the expressions v +c and
v - c. But we know from relativity you can only have v + ic and v -
ic. These produce the same hypotenuse effect as on the transverse
path, and the purported 2 units are reduced to 1. The net effect is
therefore null.
It all comes from the fact that the velocity of light is not one of
"our" velocities.
Mr. Dual Space
(If you have something to say, write an equation.
If you have nothing to say, write an essay).
Martin Hogbin
"Martin Hogbin" <sp...@hogbin.org> wrote in message news:au6r54$h93$1...@helle.btinternet.com...
>
> Bear in mind that the (1987) MMX ...
Make that 1887!
Martin Hogbin
Abhi
That means if sun cease to exist, earth will know only after eight
minutes and for eight minutes it will keep orbiting,
Around what?
Umnn..
-Abhi.
Abhi
OK. If you fear losing one year of posting on this NG, let us have just another bet.
You will send me one issue of "TIME" magazine, if you lose.
I will send you one issue of "INDIA TODAY" magazine, if I lose.
-Abhi.
Stephen Speicher
> On Sun, 22 Dec 2002 21:25:13 -0800, Stephen Speicher
> <s...@speicher.com> wrote:
>
> >On Mon, 23 Dec 2002, Graeme Prentice wrote:
> [snip]
> >
> >> I'm lost. I know they rotated the device and they also shifted its
> >> location to a mountain top
> >
> >I think you are confused. The 1887 Michelson-Morley experiment
> >was performed in the basement of Adelbert Hall, Western Reserve
> >University, in Cleveland, Ohio. Perhaps you are thinking of some
> >much later experiments.
>
> It says in this article that Michelson redid the experiment on top of
> a mountain in California because he wondered if the aether was somehow
> getting stuck to the earth.
> http://galileoandeinstein.physics.virginia.edu/lectures/michelson.html
>
I do not need to read someone's web site to learn the facts; I
already know them. After 1887 Michelson became involved in many
other experimental activities, and it was not until a decade
later that he -- absent of Morley -- performed an experiment
directly related to the one in 1887; it was again performed in a
laboratory, albeit a different one from that used a decade
earlier.
Lorentz had critiqued Michelson regarding his reliance on Stokes'
partial ether-drag theory, and Michelson became determined to
test for any ether gradient above the Earth's surface. At the
Ryerson Laboratory in Chicago, Michelson set up a large vertical
interferometer and had six inch pipes installed, 200 feet in
length and fifty feet high, around a wall in the laboratory. He
found no essential vertical gradient and he wondered if "the
earth's influence upon the ether [must be] extended to distances
on the order of the earth's diameter."[1]
As I said, perhaps you (or your reference, which I have not read)
are thinking of much later experiments which _were_ performed "on
top of a mountain in California." Dayton C. Miller became famous
for his experiments on Mount Wilson in the 1920s, and Michelson,
shortly before he died, was involved in another repeat of the
experiment on Mount Wilson. However, that was 1929, some 42 years
after the MMX, and certainly not with Morley.
[1] A.A. Michelson, "The Relative Motion of the Earth and the
Ether," _American Journal of Science_, 4th ser. 3: p. 477, 1897.
between
> The article from 1887 also makes mention of a "mountain peak"
> (on page
> 341) as being a possible location for a future experiment.
>
They say "Perhaps if the experiment should ever be tried in these
circumstances ..." The fact is, that such was not done till much
later, and it was not done by the team of Michelson-Morley.
Also, be careful about what you read even in papers such as
these. They also say, two paragraphs above, "The experiment will
therefore be repeated at intervals of three months ..." This
_was_ the intention of Michelson and Morley, but this too was
never done by them.
>
> Could you answer a question for me - does light reflect off a moving
> mirror at a different angle than off a "stationary" mirror?
>
> The 1887 document talks about "aberration" and "special laws of
> reflection" (top of page 342) and seems to indicate that if light hits
> a moving mirror the light is reflected at a different angle than if
> the mirror is stationary -
They are referring to the effect of aberration on observation.
If you have difficulty following their explanation, then look up
discussion of aberration (Arago's original 1810 experiment and
thereafter) in both the Born and the Bergmann books I mentioned.
Stephen Speicher
>
> "Graeme Prentice" <g...@paradise.net.nz> wrote in message news:dqjc0v0vcpcpbssa8...@4ax.com...
> >
> > I'm lost. I know they rotated the device and they also shifted its
> > location to a mountain top but neither of these things produced any
> > change in the interference fringes - meaning the light path lengths
> > changed by the same amount or did not change at all.
>
> I believe the idea of moving the experiment to a mountain top was
> to check out the possibility that the aether was being dragged along
> with the Earth.
>
More specifically, as in the Stokes' partial ether-drag theory
which Michelson embraced, to determine any ether gradient ranging
from full drag at the Earth's surface, decreasing outwards. Even
after Michelson performed the 1897 experiment I mentioned in a
previous post, the one where he sought a gradient in the 50 ft.
height of the laboratory, he was left with three conclusions:
"In any case we are driven to extraordinary conclusions, and the
choice lies between these three:
"1. The earth passes through the ether (or rather allows the
ether to pass through its entire mass) without appreciable
influence.
"2. The length of all bodies is altered (equally?) by their
motion through the ether.
"3. The earth in its motion drags with it the ether even at
distances of thousands of kilometers from its surface."
Even though this decade later experiment of Michelson's found no
confirmation for Stokes' partial ether-drag theory, Michelson
continued to hold onto the notion for almost three more decades.
> Such a theory would have been a nightmare, and there was
> probably sufficient astronomical evidence to rule it out anyway,
> but I guess M and M thought they had better make sure.
>
It wans't until his 1925 experiment with Gale [1] that Michelson,
and many others, became convinced that the partial ether-drag
theory had been invalidated.
[1] A.A. Michelson and H.G. Gale, "The Effect of the Earth's
Rotation on the Velocity of Light," part II, _Astrophysical
Journal_, vol. LXI (1925), pp. 140-145.
Graeme Prentice
Polasek) wrote:
>>I doubt that I'm going to be able to understand how they were able to
>>make the lengths of the two light paths the same - I know they could
>>move one mirror very small distances and they used white light, then
>>sodium light, then white light or something - but its gobbledegook
>>at this stage.
>>
>>Graeme
>I have started a new thread "Re: Gravity experiment/Michelson Morley"
>in which I more carefully analyzed the source of the null MM effect.
>
>We all agree that the sidewise path length is on a hypotenuse by
>virtue of the apparatus "skidding forward' while in transit. (An
>increase of 1 unit, say). This is standard fare.
unfortunately its not standard fare to me - if the beam splitter is
at exactly 45 degrees then the sideways path should be at exactly 90
degrees to the original path and should hit the sideways mirror at
exactly 90 degrees and then retrace its path exactly rather than be on
a hypotenuse - so my assumption is that the mirrors and beam splitter
were not at exactly 45 or 90 degrees except for the "redirector" at
the mid point of the total light path.
>
>On the updown path we calculate an increase of two units, due to the
>summing of inverses of velocity, and using the expressions v +c and
>v - c. But we know from relativity you can only have v + ic and v -
>ic. These produce the same hypotenuse effect as on the transverse
>path, and the purported 2 units are reduced to 1. The net effect is
>therefore null.
>
>It all comes from the fact that the velocity of light is not one of
>"our" velocities.
I have no idea what you mean by this but I hope to learn more about
special relativity in the near future.
Graeme
Stephen Speicher
If you do learn relativity, it will not be by dealing with people
such as this Polasek. He is a cuckoo bird, through and through.
You should rely on learning from decent texts in the field, and
only after learning at least the basics will you be able to
adequately distinguish between knowledgeable people on this
group, and the various crackpot pretenders who post here.
The couple of references I gave you previously were specifically
in regard to the MMX, and were not meant as a recommendation for
learning relativity in general. For that, I would _strongly_
suggest that you start with Taylor and Wheeler's "Spacetime
Physics," _W.H. Freeman and Co._, available online at amazon.com,
bn.co, etc, and usually available in most large book stores. This
book will give you the proper conceptual foundation for
understanding the theory, and it is geared to the non-technical
reader.
Another excellent book you might want to consider, perhaps as a
follow on, or accompanying "Spacetime Physics," is "General
Relativity From A to B," Robert Geroch, _The University of
Chicago Press_. Although the title mentions "General Relativity,"
a goodly portion of the book is devoted to the basic concepts of
special relativity.
Relativity is a truly fascinating subject to learn, and the
special theory is well within the grasp of any intelligent
person, and does not require anything more than high school
mathematics for a basic understanding. I hope you pursue your
learning.
John C. Polasek
<g...@paradise.net.nz> wrote:
>On Mon, 23 Dec 2002 14:55:49 GMT, jpol...@cfl.rr.com (John C.
>Polasek) wrote:
>
>>>I doubt that I'm going to be able to understand how they were able to
>>>make the lengths of the two light paths the same - I know they could
>>>move one mirror very small distances and they used white light, then
>>>sodium light, then white light or something - but its gobbledegook
>>>at this stage.
>>>
>>>Graeme
>>I have started a new thread "Re: Gravity experiment/Michelson Morley"
>>in which I more carefully analyzed the source of the null MM effect.
>>
>>We all agree that the sidewise path length is on a hypotenuse by
>>virtue of the apparatus "skidding forward' while in transit. (An
>>increase of 1 unit, say). This is standard fare.
>
>unfortunately its not standard fare to me - if the beam splitter is
>at exactly 45 degrees then the sideways path should be at exactly 90
>degrees to the original path and should hit the sideways mirror at
>exactly 90 degrees and then retrace its path exactly rather than be on
>a hypotenuse - so my assumption is that the mirrors and beam splitter
>were not at exactly 45 or 90 degrees except for the "redirector" at
>the mid point of the total light path.
You are thinking of sharp lines drawn with a 6H pencil. If the beam
bundle generally is headed left, but its target mirror has moved ahead
by 0.5*v*T, it will find that mirror, making an angle v/c. It will
bounce off at 'one more' v/c and finally reach 'home' having shifted
by v*T. The paths are the hypotenuse of the triangles.
>>On the updown path we calculate an increase of two units, due to the
>>summing of inverses of velocity, and using the expressions v +c and
>>v - c. But we know from relativity you can only have v + ic and v -
>>ic. These produce the same hypotenuse effect as on the transverse
>>path, and the purported 2 units are reduced to 1. The net effect is
>>therefore null.
>>
>>It all comes from the fact that the velocity of light is not one of
>>"our" velocities.
>
>I have no idea what you mean by this but I hope to learn more about
>special relativity in the near future.
Have you ever observed the number of puerile threads that endlessly
debate the problems of locomotives with flashlights shining off the
front or back, with the idea that they are trying to find a 'leak' in
special relativity? The one fact that would save all that steam would
be to realize you cannot treat c as just another velocity, to be added
to any v.
The mathematical module v + ic guarantees that light will not be toyed
with, it will not cooperate, it will always be orthogonal to anything
you can come up with. That's why I say it's not one of "our
velocities". The real axis (v) and imaginary (c) are at 90 degrees.
>Graeme
Graeme Prentice
Polasek) wrote:
>On Tue, 24 Dec 2002 09:16:05 +1300, Graeme Prentice
><g...@paradise.net.nz> wrote:
>
>>On Mon, 23 Dec 2002 14:55:49 GMT, jpol...@cfl.rr.com (John C.
>>Polasek) wrote:
>>
[snip]
>>>We all agree that the sidewise path length is on a hypotenuse by
>>>virtue of the apparatus "skidding forward' while in transit. (An
>>>increase of 1 unit, say). This is standard fare.
>>
>>unfortunately its not standard fare to me - if the beam splitter is
>>at exactly 45 degrees then the sideways path should be at exactly 90
>>degrees to the original path and should hit the sideways mirror at
>>exactly 90 degrees and then retrace its path exactly rather than be on
>>a hypotenuse - so my assumption is that the mirrors and beam splitter
>>were not at exactly 45 or 90 degrees except for the "redirector" at
>>the mid point of the total light path.
>
>You are thinking of sharp lines drawn with a 6H pencil. If the beam
>bundle generally is headed left, but its target mirror has moved ahead
>by 0.5*v*T, it will find that mirror, making an angle v/c. It will
>bounce off at 'one more' v/c and finally reach 'home' having shifted
>by v*T. The paths are the hypotenuse of the triangles.
>
I hadn't thought of the light rays having "width" (darn) - I guess I
was thinking of a "serial" stream of photons one behind the other -
effectively "one photon wide" - is that even possible?
If the light source emits a light beam that is more than "one photon
wide" but the light rays are all parallel to start with then they will
hit the beam splitter at different times - what that does to the
total path length for each of those photons I don't know - I also
don't know anything about interferometers but I suspect it doesn't
matter that the beam is more than one photon wide - it will still
show an interference pattern. If the light rays are not parallel when
they leave the light source (seems likely) then the path lengths get
more complicated. I obviously don't understand this much.
You say "the beam bundle generally is headed left" - that sounds like
more than "one photon wide" - however the target mirror is several
millimetres wide and the fact that it has moved very slightly from
where it was when the light ray hit the beam splitter seems irrelevant
to me - it sounds to me like you are thinking of a mirror that is
only one photon wide and selects only those photons coming off the
beam splitter at one specific angle.
I also don't know if the special relativity "law" about "the speed of
light is the same for all observers" affects the relative arrival time
of the photons at the interferometer but I intend to find out.
Graeme
Martin Hogbin
"Stephen Speicher" <s...@speicher.com> wrote in message
news:Pine.LNX.4.33.021223...@localhost.localdomain...
> On Mon, 23 Dec 2002, Martin Hogbin wrote:
>
> More specifically, as in the Stokes' partial ether-drag theory
> which Michelson embraced, to determine any ether gradient ranging
> from full drag at the Earth's surface, decreasing outwards.
> It wans't until his 1925 experiment with Gale [1] that Michelson,
> and many others, became convinced that the partial ether-drag
> theory had been invalidated.
>
Thanks for that.
I have heard of Stokes' partial aether-drag theory but I do not
know the details.
From what I have read about it, I suspect (with over a century
of hindsight) that the partial aether-drag theory was a bit of
a dead duck even in 1887.
Do you know how fully it addressed the following questions:
What property of matter is it that causes the aether to be
dragged with it? Mass would be the obvious choice but
it could also have been physical size or even number of
inhabitants ;-)
Was the aether modelled as a fluid (I guess that Stokes would
be the man for this) and if so was it compressible, viscous, and
did it have inertia?
To what degree were the astronomical consequences of the theory
tested? I am thinking of aberrations when large bodies passes
close to the line of sight to distant stars.
My impression is that Michelson and others were trying to get
any results at all so that a proper aether theory could then be
developed.
Martin Hogbin
John C. Polasek
<g...@paradise.net.nz> wrote:
Mr. Graeme:
Ok, Ok, it finally dawned on me. I was taken in by the lurid
descriptions found on Google. And this, after I had already worked it
out in Dual Space.
The whole story is that velocity v causes a reduction in the local
velocity of light. Of course, special relativity does not allow this
and so had to go by the slanty path reaasoning. Before you hang up,
please follow (bearing in mind V =v + ic):
Draw a horizontal line, call it cx. Draw an opposite side, call it v.
Complete the hypotenuse and call it c (of inifinity). Now you have
local reduced velocity of light (as caused by velocity)
cx = sqrt(c^2-v^2).
It comes from the principle that any local velocity is always combined
at right angles with the local velocity of light. Poking up that
little v causes cx to shorten.
Thus, in MM, the side time Ts = 2L/cx, never mind any slanty paths (of
which you were still properly suspicious). That is the relativists way
of using constant c.
And, glory be, likewise Tud = 2L/cx, the up and down times are
similarly afflicted,
In fact we have a constant value of cx here as long as we orbit the
Sun. It is reduced from the infinity value. It is the Lorentz
contraction.
The reduction in c is easily calculated from the triangle whose
included angle is v/c:
dc/c = vers(v/c) = .5*v^2/c^2 (to 1st term)
Since v/c is 10,000 or 10^4, dc/c = .5x10^8.
dc = 3*10^8*.5*10^-8 = 1.5 m/s
(this far exceeds the decrement in c due to gravity, which is 0.205
m/s).
I'm glad you brought this to my attention.
Graeme Prentice
I don't follow you but I will keep it in mind as I continue learning.
Graeme
Stephen Speicher
[In regard to Stokes' ether theory]
>
> What property of matter is it that causes the aether to be
> dragged with it? Mass would be the obvious choice but
> it could also have been physical size or even number of
> inhabitants ;-)
>
> Was the aether modelled as a fluid (I guess that Stokes would
> be the man for this) and if so was it compressible, viscous, and
> did it have inertia?
>
Stokes focused primarily on mechanisms rather than underlying
causes, and his thinking evolved somewhat over time, in part due
to his own expanding knowledge, and in part due to experiments by
himself and others. Early (circa 1845), he put forth a
perspective to differ with Fresnel's in explaining Arago's
experiment on aberration:
"I shall suppose that the earth and the planets carry a
portion of the ether along with them so that the ether
close to their surfaces is at rest relatively to their
surfaces while its velocity alters as we recede from
the surface till, at no great distance, it is at rest
in space."[1]
Stokes thought mainly in terms (as Whittaker points out[2]) of an
ether which is condensed upon entering a body, and rarefied upon
exit. By analyzing the motion of a "mass" of this ether, Stokes
arrived at the exact same drag coefficient formula as did
Fresnel, which of course was experimentally verified in Fitzeau's
experiment in 1851. This was the "aether-drag hypothesis" which
Stokes used to explain aberration "without the startling
assumption that the earth in its motion round the sun offers no
resistence to the ether."[3]
Stokes did some experimentation on diffraction which led to
explanations of ether particles in polarization, and later some
work on crystal optics which led to further clarifications on his
part regarding the ether. All of this helped to clarify his
thinking in regard to the nature of the ether, which, in my
opinion, he best explained towards the end of his life (just to
answer your question :) ).
"The supposition that the ether would resist ... a body
moving through it is derived from what we observe in
the case of solids moving through fluids, liquid or
gaseous, as the case may be. In ordinary cases of
resistance, the main representative of the work
apparently lost in propelling the solid is in the
first instance the molecular kinetic energy of the
trail of the eddies in the wake. The formation of
these eddies is, however, an indirect effect of the
internal friction, or -- if we prefer the term --
viscosity of the fluid. Now the viscosity of gases has
been explained on the kinetic theory of gases, and in
the case of a liquid we cannot well doubt that it is
connected with the constitution of the substance as not
being absolutely continuous but molecular. But if the
ether be either non-molecular, or molecular in some
totally different sense from ponderable matter, we
cannot with safety infer that the motion of a solid
through it necessarily implies resistance."[4]
This was the ultimate depth Stokes was to achieve, clearly not on
the level in which modern theory attempts to explain phenomena.
Note also that Stokes was not quite as dogmatic about the ether
as some of our modern incarnations on this group. Stokes admitted
that aberration was more easily explained by the corpuscular
theory, even though he thought the evidence to greatly favor the
undulatory theory of light. But, even accepting waves, Stokes
cautioned:
"We must be aware of applying to the mysterious ether
the gross notions which we get from the study of
ponderable matter. The ether is a substance, if
substance it may be called, respecting the very
existence of which our senses give us no direct
information: it is only through the intellect, by
studying the phenomena which nature presents us, and
finding with what admirable simplicity those of light
are explained by the supposition of the existence of
the ether, that we become convinced that there is such
a thing."[5]
> To what degree were the astronomical consequences of the theory
> tested? I am thinking of aberrations when large bodies passes
> close to the line of sight to distant stars.
>
The classic experiments, such as Arago in 1810, established the
existence of aberration, and although work was done by people
like Bessel and Doppler, everything entered into the world of
electromagnetics on the heels of Faraday and Maxwell. Most
experimental work which was meant to quantify the ether was
terrestrial in origin, though note that Stokes himself used his
almost fifty year-old aether-drag hypothesis to explain the
precession of Encke's comet in 1893. This was, however, atypical
of the times.
> My impression is that Michelson and others were trying to get
> any results at all so that a proper aether theory could then be
> developed.
>
"What would be the use of such extreme refinement in
the science of measurement? Very briefly and in
general terms the answer would be that in this
direction the greater part of all future discovery must
lie. The more important fundamental laws and facts of
physical science have all been discovered, and these
are now so firmly established that the possibility of
their ever being supplanted in consequence of new
discoveries is exceedingly remote."[6]
Michelson continues on to describe that there are exceptions to
these laws and that experimental science continues on with
improved measuring instruments. Though first published in 1903,
these words were first spoken by Michelson in a series of eight
lectures he gave in 1899 at the Lowell Institute.
Michelson was a great experimentalist, not a theorist, and he
lacked both the perspective and knowledge to be able to conceive
of what his theoretical betters could and would achieve. He was a
man who was in love with light, and he devoted most of his life
attempting to uncover more and more facts about same, but he had
a certain naivete when it came to theory. At the very end of
reference [6] which I quoted from above, in the final Lecture
VIII titled, simply, "The Ether," Michelson ends with:
"The phenomenon of the aberration of the fixed stars
can be accounted for on the hypothesis that the ether
does not partake of the earth's motion in its
revolution about the sun. All experiments for testing
this hypothesis have, however, given negative results,
so that the theory may still be said to be in an
unsatisfactory condition."
Michelson simply held onto the Stokes theory until he himself
experimentally invalidated it in 1925. But, Michelson continued
to cling to the ether as a belief, even though he had no theory
anymore to explain what was explained by relativity.
[1] George G. Stokes, "On the Aberration of Light,"
_Philosophical Magazine_, 3rd ser 27: p. 9, July 1845.
[2] Sir Edmund Whittaker, "A History of the Theories of Aether &
Electricity," _Dover_, 1951/1989.
[3] George G. Stokes, "On the Constitution of the Luminiferous
Aether Viewed with Reference to the Phenomenon of the Aberration
of Light," _Philosophical Magazine_, 3rd ser 29: p. 6, July 1846.
[4] George G. Stokes, "Presidential Address at Anniversary
Meeting at Victoria Institute, June 29, 1893," _Nature_, July 27,
1893.
[5] George G. Stokes, "On Light: First Course on the Nature of
Light Delivered at Aberdeen in Novemberer, 1883," p. 17. (This
was the Burnett Lectures at Aberdeen.)
[6] A. A.Michelson, "Light Waves and Their Uses," _The University
of Chicago Press_, 1903.
Abhi
> On Tue, 24 Dec 2002, Martin Hogbin wrote:
>
> "The phenomenon of the aberration of the fixed stars
> can be accounted for on the hypothesis that the ether
> does not partake of the earth's motion in its
> revolution about the sun. All experiments for testing
> this hypothesis have, however, given negative results,
> so that the theory may still be said to be in an
> unsatisfactory condition."
>
Umnn..
Now I will have to read this "aberration" thing. Damn it. You people
make me to work overtime. why don't you just accept my "Time Theory"
and let me go?
-Abhi.
Dirk Van de moortel
They don't accept your theory but let you go nevertheless ;-)
Dirk Vdm
Martin Hogbin
> On Tue, 24 Dec 2002, Martin Hogbin wrote:
Thanks for your comments on Stokes.
[Quote from Stokes]
> "We must be aware of applying to the mysterious ether
> the gross notions which we get from the study of
> ponderable matter. The ether is a substance, if
> substance it may be called, respecting the very
> existence of which our senses give us no direct
> information: it is only through the intellect, by
> studying the phenomena which nature presents us, and
> finding with what admirable simplicity those of light
> are explained by the supposition of the existence of
> the ether, that we become convinced that there is such
> a thing."[5]
It is a pity that some of the aether crackpots do not heed these
wise words.
--------------------------------------------------------------
> Michelson simply held onto the Stokes theory until he himself
> experimentally invalidated it in 1925. But, Michelson continued
> to cling to the ether as a belief, even though he had no theory
> anymore to explain what was explained by relativity.
As an experimentalist Michelson no doubt found a null result
extremely unsatisfying, although it turned out to be one of the
most important null results in the history of physics.
Martin Hogbin
Abhi
No way. My theory does not predict that.
-Abhi.
John Kennaugh
>Second question : I would like to understand the Michaelson Morley
>experiment but I have the impression it's a slightly contentious issue
>- is there a "mainstream" explanation for this experiment that most
>the result of the experiment - preferably something suitable for a
>person not directly involved in physics or mathematics.
OK the starting point is that it was believed that there is no substance
called light but that it is a disturbance propagated in a medium which
they called the aether. Rather like sound waves travelling through air.
As light travels through a vacuum the assumption was that even a vacuum
is filled with this propagating medium. The speed of propagation of a
disturbance in a medium is constant w.r.t the medium of propagation.
Now as the earth is travelling through space at high speed it must, it
was argued be travelling relative to the aether. The MM experiment was
devised to detect that motion by looking for a difference in time it
takes for light to travel there and back in two arms of the apparatus at
right angles. By turning the apparatus it was assumed that a position
would be reached where one arm was pointing in the earth's direction of
travel through the aether and the other at right angles to it. It was
further assumed that in the highly unlikely event that we happen to be
stationary w.r.t the aether at one point in our orbit we would not be at
another. No matter how they turned the apparatus and no matter what time
of the year they tried it they detected no difference in the two arms of
the apparatus.
Interpretations come into 3 categories.
1/ That there is nothing wrong with the theory as it stands:
1.1 One school of thought is that the experiment was ill conceived and
would not have detected the aether anyway. See posting by John C.
Polasek.
1.2 That although light is a propagated disturbance propagated in the
aether and travelling at a constant speed w.r.t the aether, anything
travelling through the aether is physically shortened in the direction
of travel. This makes one arm of the MM apparatus shorter by just the
amount needed to cancel out the time difference. (Lorenz)
2/ Relativity - That light is a propagated disturbance in a medium but
that for some unexplained reason the medium always appears stationary
w.r.t the observer, making the speed of light constant w.r.t the
observer. This is the origin of relativity. Each observer has his own
aether stretching throughout the universe. The aether has only one
property, it controls the speed at which light travels. Nowadays the
term 'aether' is not used and the term 'frame of reference' is
substituted. Modern ideas as to what light IS are somewhat vague.
3/ Ballistic theory. That light is not a propagated disturbance but a
'substance' in its own right which leaves the source and travels through
space. MM showed that there was no aether, and that there is nothing in
space which can effect the speed of light. You are left with a source
chucking out light at a constant speed c relative to the source
independent of whether anyone observes it or not. This is a perfectly
adequate explanation of the MM null result. This is really a return to
an idea put forward by Newton that light was in fact particles
(corpuscles he called them). They do exist. We now call them photons.
The interesting thing is that at the time relativity was accepted there
was no experimental evidence to rule out option 3. To an objective
observer this would, at that time, seem to be the obvious
interpretation. As relativity required clocks to go at different speeds,
measuring rods to change length, events to take place at different times
for different observers and the same light to leave the same source at
different speeds to travel to different observers no one in his right
mind would opt for Relativity rather than the ballistic theory but they
did. As far as I can see the reason was that no one was willing to
return to a theory which they had rejected 200 years previously.
Einstein started his justification of relativity with 'light is a
propagated wave' showing a certain lack of objectivity.
Of course despite the dubious origins of relativity we all now know that
relativity is right and that anyone who suggests otherwise is a crank.
--
John Kennaugh
Graeme Prentice
It's just occurred to me that I don't know whether a sound wave
*propogates* at a different speed (relative to air) in the direction
the source is moving compared to other directions or whether its just
that the peaks are closer together in that direction. Its a long time
since I did physics at school. Maybe the interferometer in the MM
experiment was detecting a difference in the closeness of the peaks
rather than a difference in propogation time.
>
>Interpretations come into 3 categories.
>
[snip]
>
>2/ Relativity - That light is a propagated disturbance in a medium but
>that for some unexplained reason the medium always appears stationary
>w.r.t the observer, making the speed of light constant w.r.t the
>observer. This is the origin of relativity. Each observer has his own
>aether stretching throughout the universe. The aether has only one
>property, it controls the speed at which light travels. Nowadays the
>term 'aether' is not used and the term 'frame of reference' is
>substituted. Modern ideas as to what light IS are somewhat vague.
>
>3/ Ballistic theory. That light is not a propagated disturbance but a
>'substance' in its own right which leaves the source and travels through
>space. MM showed that there was no aether, and that there is nothing in
>space which can effect the speed of light. You are left with a source
>chucking out light at a constant speed c relative to the source
>independent of whether anyone observes it or not. This is a perfectly
>adequate explanation of the MM null result. This is really a return to
>an idea put forward by Newton that light was in fact particles
>(corpuscles he called them). They do exist. We now call them photons.
>
I don't understand this "ballistic theory" - that implies to me the
"bullet from a gun" mechanics where the speed of the gun adds to the
speed of the bullet - then you'd have to guess at what speed the
"bullet" bounces off the mirrors at. You couldn't actually tell if
the speed of the gun adds to the speed of the bullet because at the
beam splitter, the "bullet" fires off in both directions at the same
speed (perhaps).
>
>Of course despite the dubious origins of relativity we all now know that
>relativity is right and that anyone who suggests otherwise is a crank.
I'm working on that assumption! Everyone says this experiment is
simple but I haven't understood it yet. I'm thinking of hiring a PhD
student from my local university to try to explain it to me.
Thanks for taking the trouble to reply.
Graeme
Martin Hogbin
"Graeme Prentice" <g...@paradise.net.nz> wrote in message news:nv8n0v41jg19f6iup...@4ax.com...
>
> I'm working on that assumption! Everyone says this experiment is
> simple but I haven't understood it yet. I'm thinking of hiring a PhD
> student from my local university to try to explain it to me.
What is it exactly that you do not understand about the MMX?
Is it its original purpose, to measure the aether drift, or do you want
to know how it fits in with relativity?
Martin Hogbin
Martin Hogbin
"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message news:JgjqsSBG...@kennaugh.demon.co.uk...
> Interpretations come into 3 categories.
>
> 1/ That there is nothing wrong with the theory as it stands:
>
> 1.1 One school of thought is that the experiment was ill conceived and
> would not have detected the aether anyway. See posting by John C.
> Polasek.
Graeme asked for a mainstream explanation.
> 1.2 That although light is a propagated disturbance propagated in the
> aether and travelling at a constant speed w.r.t the aether, anything
> travelling through the aether is physically shortened in the direction
> of travel. This makes one arm of the MM apparatus shorter by just the
> amount needed to cancel out the time difference. (Lorenz)
>
> 2/ Relativity - That light is a propagated disturbance in a medium but
> that for some unexplained reason the medium always appears stationary
> w.r.t the observer, making the speed of light constant w.r.t the
> observer.
This is, to say the least, a rather idiosyncratic description of relativity.
> This is the origin of relativity. Each observer has his own
> aether stretching throughout the universe. The aether has only one
> property, it controls the speed at which light travels. Nowadays the
> term 'aether' is not used and the term 'frame of reference' is
> substituted. Modern ideas as to what light IS are somewhat vague.
Your reference to 'what light IS' is somewhat vague.
> 3/ Ballistic theory. That light is not a propagated disturbance but a
> 'substance' in its own right which leaves the source and travels through
> space. MM showed that there was no aether, and that there is nothing in
> space which can effect the speed of light. You are left with a source
> chucking out light at a constant speed c relative to the source
> independent of whether anyone observes it or not. This is a perfectly
> adequate explanation of the MM null result. This is really a return to
> an idea put forward by Newton that light was in fact particles
> (corpuscles he called them). They do exist. We now call them photons.
Newtonian corpuscles and photons are nothing like the same.
> The interesting thing is that at the time relativity was accepted there
> was no experimental evidence to rule out option 3. To an objective
> observer this would, at that time, seem to be the obvious
> interpretation.
Apart from the small matter that Maxwell's equations showed
the existence of electromagnetic waves, travelling at the speed
of light. This and many other wave effects of light tended to
make people think that light should be a wave.
> As relativity required clocks to go at different speeds,
> measuring rods to change length, events to take place at different times
> for different observers and the same light to leave the same source at
> different speeds to travel to different observers no one in his right
> mind would opt for Relativity rather than the ballistic theory but they
> did. As far as I can see the reason was that no one was willing to
> return to a theory which they had rejected 200 years previously.
> Einstein started his justification of relativity with 'light is a
> propagated wave' showing a certain lack of objectivity.
The ballistic theory was disproved in 1913 by de Sitter.
Subsequent experimenters confirmed this.
> Of course despite the dubious origins of relativity
What do you mean by 'dubious origins.of relativity'?
> we all now know that relativity is right
What do you mean by 'relativity is right'?
>and that anyone who suggests otherwise is a crank.
You said it.
Martin Hogbin
Graeme Prentice
I don't like to take up your time as I'm probably slow to pick things up -
but its not the aether side of it that I want to understand, its the
"real" modern day explanation for why the interference fringes don't
change or why there's no phase difference between the two light pulses
when they reach the interferometer. I tried to calculate the length of
the two light paths and got lost. I barely know what an interferometer is
though so I need to read up on that.
In my other post "moving clocks run fast", the answer someone gave me
indicates to me that I don't understand the light clock experiment either.
In that post, I wrote a calculation that was all a "doppler effect" type
calculation yet the person who answered me said there's a time dilation
effect as well - but I can't see what that is yet. I am frustrated with
the explanation in the book I have because it says that a stationary
observer sees the light pulse within the light clock move on a
"hypotenuse" i.e. a greater distance than the person on the train sees -
therefore a clock tick takes a longer time for the stationary observer -
however this seems like a simplification to me because for the stationary
observer to "see the light pulse move on a hypotenuse" he has to see it
start its journey and finish its journey. The information that tells the
observer that journey has started and finished takes a different amount of
time to reach the observer - but the book doesn't mention this and it
doesn't seem to appear in the famous time dilation formula either.
The angle the light pulse within the light clock moves at relative to the
mirrors also puzzles me - if a line were drawn along the path of the
light pulse relative to earth, it intersects the mirrors at an angle -
this means the "initial photon" has to be fired at an angle to start with
- the book doesn't mention this. If you take a stationary train with a
light pulse in it going vertically up and down and give the train
instantaneous horizontal velocity, the light pulse within the clock does
not move with the train. I know the person on the train sees the light
pulse move at 90 degrees with respect to the mirrors. Also I can see that
the person on the train might be "tricked" into thinking that the light
clock is ticking over at the same rate as when the train wasn't moving but
I don't see the significance of this yet.
According to me, if the train goes 100 metres up the track and then 100
metres back to where it started (all at the same theoretical instantaneous
velocity) the stationary observer and the person on the train would count
the same number of clock ticks.
Also I still don't know what it means that "the speed of light is the same
in all frames of reference". Is there some non intuitive magic in this
that I just have to accept because experiments show it to be true or can
it be understood from "logical analysis".
Graeme
Abhi
>
> Also I still don't know what it means that "the speed of light is the same
> in all frames of reference".
> Graeme
It means that if you have two frames and if you move one frame with
velocity v with relative to stationary frame, you will measure same
velocity of both frames.
whatever does that mean. Believe it.
Umnn... What?... You don't believe me?... I am "super
intellectual".... Are you idiot, moron, crank?... You don't understand
such simple things..... Who is your teacher?... Is he crank?..... Are
your friends crank?... You don't understand Einstein, oh my God...
what a idiot person, go away.... run.... in any frame, just with c.
-Abhi.
Martin Hogbin
"Graeme Prentice" <g...@paradise.net.nz> wrote in message news:0aao0vokktu8dnrrt...@4ax.com...
> On Fri, 27 Dec 2002 09:38:56 +0000 (UTC), "Martin Hogbin"
> <sp...@hogbin.org> wrote:
>
> >
> >"Graeme Prentice" <g...@paradise.net.nz> wrote in message news:nv8n0v41jg19f6iup...@4ax.com...
> >>
> >> I'm working on that assumption! Everyone says this experiment is
> >> simple but I haven't understood it yet. I'm thinking of hiring a PhD
> >> student from my local university to try to explain it to me.
> >
> >What is it exactly that you do not understand about the MMX?
> >
> >Is it its original purpose, to measure the aether drift, or do you want
> >to know how it fits in with relativity?
>
> I don't like to take up your time as I'm probably slow to pick things up -
> but its not the aether side of it that I want to understand, its the
> "real" modern day explanation for why the interference fringes don't
> change or why there's no phase difference between the two light pulses
> when they reach the interferometer. I tried to calculate the length of
> the two light paths and got lost. I barely know what an interferometer is
> though so I need to read up on that.
Firstly, at the risk of boring you, let me repeat that the purpose of the
MMX was to measure the aether drift. To see its scientific importance
it should be analysed from the perspective of a 'rigid' aether.
The explanation for there being no fringe shift according to relativity
is really simple. I could turn the question round and ask you why
you think that there should be a fringe shift.
The postulates of relativity say that (non-accelerated) all motion is
relative and that light travels at a constant speed relative to any inertial
observer.
So, in the MMX interferometer, the speed of light down both arms is
exactly c, the speed it always is. When the interferometer is rotated,
the speed remains at c. The direction of the light is unimportant.
> In my other post "moving clocks run fast"...
I have answered your questions in that thread.
> Also I still don't know what it means that "the speed of light is the same
> in all frames of reference". Is there some non intuitive magic in this
> that I just have to accept because experiments show it to be true or can
> it be understood from "logical analysis".
Strictly speaking it is a postulate, or of you prefer and axiom, of relativity.
Einstein just made it up!
Before you throw your arms up in horror, however, let me try to make his
second postulate seem more reasonable to you.
I am going to describe some experiments. Some of them have been done,
some could be done, and some are impractical to do exactly as described,
but in all cases we know what the answer would be from the results of
real experiments (probably more complicated than the ones I describe)
that have actually been performed.
Place two light detectors a measured distance apart. Take two accurate
clocks initially both at the location of one of the light detectors and
synchronise them while they are together. Move one of the clocks slowly
and carefully to the location of the second light detector. Now send
a pulse of light from a laser that is stationary with respect to the light
detectors so that it passes from one detector to the next. Arrange
for the detectors and clocks to record the time that the light pulse passed
by. We now have some apparatus to measure the speed of light.
All tests are done in a vacuum.
Let us call the speed of light that we get from our first experiment c.
We could repeat the experiment with a different colour light, the
result would also be c.
Let us now repeat the experiment but arrange for the laser to be
moving rapidly towards the apparatus along the line of the two
detectors. The result is still c.
Try again with the laser moving away from the apparatus, the
answer is still c.
Move the laser and the measuring apparatus together at some
constant high speed (this is what the MMX did), still c.
Have two sets of apparatus and have one stationary with respect
to the laser and the other moving rapidly towards it. Both get
the same answer, c.
Whatever you do (in a vacuum, not accelerating) you always get
the same answer, c. Remember these are all experiments that, in
principle, could be done and that many actual experiments have
been done that allow us to predict what the results will be.
This is weird, like nothing else in physics, it is not like sound,
it is not like firing bullets.
With this experimental evidence it might be tempting to say
Einstein's postulate about the constant speed of light is not
necessary. If you want I can explain why it is.
Martin Hogbin
John Kennaugh
<sp...@hogbin.org> writes
>
>"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message
>news:JgjqsSBG...@kennaugh.demon.co.uk...
>> Interpretations come into 3 categories.
>>
>> 1/ That there is nothing wrong with the theory as it stands:
>>
>> 1.1 One school of thought is that the experiment was ill conceived and
>> would not have detected the aether anyway. See posting by John C.
>> Polasek.
>
>Graeme asked for a mainstream explanation.
He wasn't getting it as the above mentioned posting indicated. I thought
I would give him a resume of what was available.
>
>> 1.2 That although light is a propagated disturbance propagated in the
>> aether and travelling at a constant speed w.r.t the aether, anything
>> travelling through the aether is physically shortened in the direction
>> of travel. This makes one arm of the MM apparatus shorter by just the
>> amount needed to cancel out the time difference. (Lorenz)
>>
>> 2/ Relativity - That light is a propagated disturbance in a medium but
>> that for some unexplained reason the medium always appears stationary
>> w.r.t the observer, making the speed of light constant w.r.t the
>> observer.
>
>This is, to say the least, a rather idiosyncratic description of relativity.
>
In what way? Please explain?
>> This is the origin of relativity. Each observer has his own
>> aether stretching throughout the universe. The aether has only one
>> property, it controls the speed at which light travels. Nowadays the
>> term 'aether' is not used and the term 'frame of reference' is
>> substituted. Modern ideas as to what light IS are somewhat vague.
>
>Your reference to 'what light IS' is somewhat vague.
>
I have heard various descriptions including that it is a wave of
probability, it is a mathematical wave etc. I do not really understand
what the modern view is. In my simple terms - is it a disturbance in
something where the substance does not move (the old idea) or does
something of substance leave the source and travel through space until
it reaches its destination? Franz Heymann's description went:
"Light is concerned with photons.
Photons are, as best we can determine, point particles.
They are characterised by
Zero mass
Spin 1
Boson statistics
Interact with charge according to the EM vertex function
Being bosons, there is no limit to the number which can occupy one
wave function.
The wave function which specifies the dynamics of a free photon is a
solution of Maxwell's equations.
In general, a beam of light consists of a vast number of such photons
all in the same quantum mechanical state."
That suggests something particle like which leaves the source rather
than a disturbance in something which does not itself move and which
determines its speed. The latter was however central to Einstein's
thinking and has now been abandoned. The problem with the FH description
is that the reason/mechanism why light should travel at a speed constant
w.r.t the observers frame of reference is not obvious.
>> 3/ Ballistic theory. That light is not a propagated disturbance but a
>> 'substance' in its own right which leaves the source and travels through
>> space. MM showed that there was no aether, and that there is nothing in
>> space which can effect the speed of light. You are left with a source
>> chucking out light at a constant speed c relative to the source
>> independent of whether anyone observes it or not. This is a perfectly
>> adequate explanation of the MM null result. This is really a return to
>> an idea put forward by Newton that light was in fact particles
>> (corpuscles he called them). They do exist. We now call them photons.
>
>Newtonian corpuscles and photons are nothing like the same.
>
Explain that. As far as I am concerned they are the same although our
knowledge of photons is obviously greater than Newton's.
>> The interesting thing is that at the time relativity was accepted there
>> was no experimental evidence to rule out option 3. To an objective
>> observer this would, at that time, seem to be the obvious
>> interpretation.
>
>Apart from the small matter that Maxwell's equations showed
>the existence of electromagnetic waves, travelling at the speed
>of light. This and many other wave effects of light tended to
>make people think that light should be a wave.
Maxwell assumed a fixed Aether and that c was the speed of propagation
w.r.t that aether. MM showed it wasn't unless you accept either 1.1 or
1.2. Einstein took Maxwell's Aether and decided it was stationary w.r.t
the observer. I cannot see that mathematically it would make any
difference if you decided to make it stationary w.r.t the source and it
would be the more obvious of the two. The idea that the source would
control the speed of light it emits is surely more reasonable than that
the observer does?
>
>> As relativity required clocks to go at different speeds,
>> measuring rods to change length, events to take place at different times
>> for different observers and the same light to leave the same source at
>> different speeds to travel to different observers no one in his right
>> mind would opt for Relativity rather than the ballistic theory but they
>> did. As far as I can see the reason was that no one was willing to
>> return to a theory which they had rejected 200 years previously.
>> Einstein started his justification of relativity with 'light is a
>> propagated wave' showing a certain lack of objectivity.
>
>The ballistic theory was disproved in 1913 by de Sitter.
>Subsequent experimenters confirmed this.
Many doubts have been expressed regarding de Sitter as I am sure you are
aware. In any case relativity had been generally accepted prior to that.
Had the more logical ballistic theory been accepted and de Sitters work
caused a rethink you would have a point. Subsequent experiments do not
enter into it as my argument is that the decision *at the time* was the
result of an 'unexplained reason', dogma and some exceedingly dubious
reasoning on the part of Einstein while totally ignoring what was a much
simpler explanation. If the result is the right answer it is truly
remarkable.
>
>> Of course despite the dubious origins of relativity
>
>What do you mean by 'dubious origins.of relativity'?
>
see above
>> we all now know that relativity is right
>
>What do you mean by 'relativity is right'?
>
sorry I forgot the :^)
>>and that anyone who suggests otherwise is a crank.
>
>You said it.
--
John Kennaugh
Martin Hogbin
"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message news:FqnJuLGR...@kennaugh.demon.co.uk...
> In message <auhao7$j13$1...@venus.btinternet.com>, Martin Hogbin
> <sp...@hogbin.org> writes
> >
> >"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message
>
> In what way? Please explain?
Nothing in relativity requires light to be a 'propagated disturbance
in a medium', in fact one of the main points of relativity is that a
medium is not required at all.
-----------------------------------------------------------------
> >Your reference to 'what light IS' is somewhat vague.
> >
> I have heard various descriptions including that it is a wave of
> probability, it is a mathematical wave etc. I do not really understand
> what the modern view is.
This seem to me to be because you insist that light must be explained
in terms of everyday concepts.
> In my simple terms - is it a disturbance in
> something where the substance does not move (the old idea) or does
> something of substance leave the source and travel through space until
> it reaches its destination?
Why must it be either? Light is light.
Franz Heymann's description went:
<Snip Heymann's list of what we know about light>
> That suggests something particle like which leaves the source rather
> than a disturbance in something which does not itself move and which
> determines its speed.
Once again you are trying to fit light into your pre-conceived notions.
> The problem with the FH description
> is that the reason/mechanism why light should travel at a speed constant
> w.r.t the observers frame of reference is not obvious.
'Mechanism', there is your problem, you are looking for an
explanation in terms of everyday phenomena.
> >> (corpuscles ...). They do exist. We now call them photons.
> >
> >Newtonian corpuscles and photons are nothing like the same.
> >
> Explain that. As far as I am concerned they are the same although our
> knowledge of photons is obviously greater than Newton's.
Newton's corpuscles were classical objects that would be
expected to obey the laws of classical mechanics. They
would have locations and trajectories just like any other
classical object.
With a photon you must forget many of the classical notions.
A photon does not have a trajectory or a position. It does
however carry momentum.
------------------------------------------------------------
> >> The interesting thing is that at the time relativity was accepted there
> >> was no experimental evidence to rule out [a ballistic theory].
> >> To an objective observer this would, at that time, seem to be
> >> the obvious interpretation.
> >Apart from the small matter that Maxwell's equations showed
> >the existence of electromagnetic waves, travelling at the speed
> >of light. This and many other wave effects of light tended to
> >make people think that light should be a wave.
>
> Maxwell assumed a fixed Aether and that c was the speed of propagation
> w.r.t that aether. MM showed it wasn't...
Yes. Physicists thought they had got it cracked. Light was an EM wave
that travelled at a fixed speed through the rigid aether. But, as you say,
the MMX disproved this.
My point was that, because of Maxwell's equations and interference
phenomena, it was not easy to go back to regarding light as a classical
(the only kind they had then) particle.
----------------------------------------------------------------
> 1.2. Einstein took Maxwell's Aether and decided it was stationary w.r.t
> the observer.
No, Einstein took Maxwell's aether and decided it was unnecessary.
An aether which is stationary with respect to the observer has never
been part of relativity.
> The idea that the source would
> control the speed of light it emits is surely more reasonable than that
> the observer does?
I agree this was an option but it is not the one Einstein took.
> >The ballistic theory was disproved in 1913 by de Sitter.
> >Subsequent experimenters confirmed this.
> Many doubts have been expressed regarding de Sitter as I am sure you are
> aware.
Yes, later it was shown that extinction effects reduce the validity
of his work but that is based on the assumption that light is an EM wave.
> In any case relativity had been generally accepted prior to that.
> Had the more logical ballistic theory been accepted and de Sitters work
> caused a rethink you would have a point. Subsequent experiments do not
> enter into it as my argument is that the decision *at the time* was the
> result of an 'unexplained reason', dogma and some exceedingly dubious
> reasoning on the part of Einstein while totally ignoring what was a much
> simpler explanation.
Einstein was quite clear that his theory was based on postulates.
It is also clear that intuition played an important part in his work but
there is no dogma or 'dubious reasoning'.
I do not understand what your complaint is. Einstein was free
to present his own theory as he saw fit. He did so in a very
proper way, making clear what were postulates and what
were logical deductions from these postulates.
> If the result is the right answer it is truly remarkable.
Agreed.
Nothing that I can see above makes the origins of
relativity dubious
> >> we all now know that relativity is right[:^)]
If by 'right' you mean 'is in agreement with experiment'
then I agree with you.
If by 'right' you mean that relativity is what is written in 'The
Official Cosmic Rule Book', then who knows? Physicists
do not claim to have access to this work.
Martin Hogbin
Abhi
>
> > The idea that the source would
> > control the speed of light it emits is surely more reasonable than that
> > the observer does?
>
> I agree this was an option but it is not the one Einstein took.
>
Umnnn.....????
So laws of this universe can be decided by "choice". I went to buy
T-shirt. I had many options of colors. But I chose only "blue". Now
this "blue" color is the ONLY and ULTIMATE color in this universe for
me which forms second postulate of my "theory of nonsense".
Wow...
-Abhi.
Martin Hogbin
"Abhi" <discov...@yahoo.co.in> wrote in message news:4bd62e7c.02122...@posting.google.com...
> So laws of this universe can be decided by "choice".
Yes. Provided that the laws agree with experiment. It seem that there
are some people who understand this and some who do not.
> Wow...
Some people find this fact remarkable.
Martin Hogbin
Abhi
> "Abhi" <discov...@yahoo.co.in> wrote in message news:4bd62e7c.02122...@posting.google.com...
>
> > So laws of this universe can be decided by "choice".
>
> Yes. Provided that the laws agree with experiment. It seem that there
> are some people who understand this and some who do not.
How about twisting the interpretation of experimental result to fit in
your "choice"?
I mean MMX null result, stellar aberration can be explained other way.
Sorry Martin, you lose.
-Abhi.
Graeme Prentice
<sp...@hogbin.org> wrote:
Thanks for the example of the two clocks. I've replied to you in the
"moving clocks run fast" thread. Hope that's ok.
Graeme
John Kennaugh
>
>"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message
>news:FqnJuLGR...@kennaugh.demon.co.uk...
>> In message <auhao7$j13$1...@venus.btinternet.com>, Martin Hogbin
>> <sp...@hogbin.org> writes
>> >
>> >"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message
>>
>> >This is, to say the least, a rather idiosyncratic description of relativity.
>
>> In what way? Please explain?
>
>Nothing in relativity requires light to be a 'propagated disturbance
>in a medium', in fact one of the main points of relativity is that a
>medium is not required at all.
I am talking about a decision made at a particular point in history and
the thinking behind it. You are confusing modern thinking (which in part
resulted from that decision) with the thinking which contributed to the
decision.
Prior to Maxwell, light was considered to be a mechanical disturbance in
a universal mechanical aether which needed to be a solid with a
stiffness greater than steel. Maxwell's aether was also universal but
had to propagate an electromagnetic disturbance. In Maxwell's equations
c is the speed of propagation of the electromagnetic disturbance in
Maxwell's aether. When MM disproved the universal aether, Einstein
postulated that the speed of light is constant w.r.t the observer. As c
is the speed of propagation in Maxwell's aether, then unless you throw
out Maxwell's equations, saying c is constant w.r.t the observer, is
mathematically the same as saying the observer is stationary w.r.t
Maxwell's aether.
In a book co-authored by Einstein called "The Evolution of Physics" the
argument went as follows:
1/ Light is a propagated wave propagated by a medium called the Aether.
The velocity of a wave is a function of the medium which propagates it
and its velocity can only be effected by the source if the movement of
the source causes movement of the medium. Aether drag experiments,
passing light close to heavy rotating flywheels has shown that they had
no effect on the light passing close to them hence the speed of light
cannot be effected by the speed of the source.
2/ Although the speed of light might be expected to vary with the speed
of the observer Michelson and Morley had shown that not to be the case
so it is a strange but indisputable fact that the velocity of light is
constant independent of the velocity of the source or the observer.
That in a nut shell is both Einstein's justification for relativity and
his reason for rejecting the ballistic alternative. The concept of the
aether is absolutely central to his thinking and was inherent in the
second postulate at the time it was postulated. However:
Q: why is the speed of light constant w.r.t the observer
A: because the observer is always stationary w.r.t the Aether.
Q: why is the observer always stationary w.r.t the aether.
A: Because Einstein postulated that it was,
Q: How did Einstein justify his postulate.
A: You don't have to justify a postulate. If you could it wouldn't be a
postulate it would be a deduction.
If you study that you find that the aether is redundant:
Q: why is the speed of light constant w.r.t the observer
A: Because Einstein postulated that it was.
as you rightly say
>in fact one of the main points of relativity is that a
>medium is not required at all.
However if you refer to the book quoted above Einstein says "it is a
strange but indisputable fact". He was using the word 'postulate' in
accordance with the alternative dictionary definition as 'a self evident
truth' something he didn't have to prove because everyone accepted it to
be the case.
>> >Your reference to 'what light IS' is somewhat vague.
>> >
>> I have heard various descriptions including that it is a wave of
>> probability, it is a mathematical wave etc. I do not really understand
>> what the modern view is.
>
>This seem to me to be because you insist that light must be explained
>in terms of everyday concepts.
>
>> In my simple terms - is it a disturbance in
>> something where the substance does not move (the old idea) or does
>> something of substance leave the source and travel through space until
>> it reaches its destination?
>
>Why must it be either? Light is light.
Light is a real physical phenomena which requires a real physical means
of getting from source to destination. The two possibilities I have
outlined are all I can see. That may be a limitation in my perception.
If you have a third alternative I am perfectly happy to consider it.
"Light gets from A to B by hitching a lift on a postulate" does not
appeal I am afraid. Neither does "it gets from A to B by obeying a
differential equation".
>
>> >> (corpuscles ...). They do exist. We now call them photons.
>> >
>> >Newtonian corpuscles and photons are nothing like the same.
>> >
>> Explain that. As far as I am concerned they are the same although our
>> knowledge of photons is obviously greater than Newton's.
>
>Newton's corpuscles were classical objects that would be
>expected to obey the laws of classical mechanics. They
>would have locations and trajectories just like any other
>classical object.
>
>With a photon you must forget many of the classical notions.
>A photon does not have a trajectory or a position. It does
>however carry momentum.
Again I am talking about a decision made at a particular point in
history and the thinking behind it. You are confusing modern thinking
with the thinking which contributed to the decision. At the time it had
been discovered that light was in discreet lumps. Most unwavelike and
made to measure for the ballistic theory. As for Photons not having a
trajectory nor a position - they go from source to destination in a
straight line and arrive at a specific time which can be detected. That
is as near a classical particle as I require it to be. Or putting it
another way it would be unreasonable to expect Newton to have come any
closer in the 17th century.
>
>Yes. Physicists thought they had got it cracked. Light was an EM wave
>that travelled at a fixed speed through the rigid aether. But, as you say,
>the MMX disproved this.
>
>My point was that, because of Maxwell's equations and interference
>phenomena, it was not easy to go back to regarding light as a classical
>(the only kind they had then) particle.
'it was not easy to go back' = dogma. The wave theory had seemed a
better option than the corpuscular theory *because* of the hypothesis of
the universal aether. Post MM the theory they believed in had been left
with no invisible means of support and the photon had been discovered.
Logically where else was there to go other than the alternative they had
rejected? Headlines - "Wave theory scuppered, corpuscular theory
vindicated".
There is no logic in opting for a theory where the speed of light is
constant w.r.t the observer when there is absolutely no conceivable
reason why it should be. Read again Einstein's justification above. It
doesn't make sense. It is flawed logic. As you say it was not easy to
go back and *anything* was easier to accept than admitting they had been
wrong for 200 years. Abandoning universal time etc. etc. was the price
they were willing to pay to preserve their beliefs. That is what I mean
when I refer to its dodgy origins.
>>Einstein took Maxwell's Aether and decided it was stationary w.r.t
>> the observer.
>
>No, Einstein took Maxwell's aether and decided it was unnecessary.
>An aether which is stationary with respect to the observer has never
>been part of relativity.
See above. I don't believe that Einstein ever completely rejected the
concept of the aether. He is reported as saying "... we have not proven
that the Aether does not exist, we have only proven that we do not need
it (for calculations)".
--
John Kennaugh
Martin Hogbin
"Abhi" <discov...@yahoo.co.in> wrote in message news:4bd62e7c.02122...@posting.google.com...
> "Martin Hogbin" <sp...@hogbin.org> wrote in message news:<auksvl$a4d$1...@helle.btinternet.com>...
> > "Abhi" <discov...@yahoo.co.in> wrote in message news:4bd62e7c.02122...@posting.google.com...
> >
> > > So laws of this universe can be decided by "choice".
> >
> > Yes. Provided that the laws agree with experiment. It seem that there
> > are some people who understand this and some who do not.
>
> How about twisting the interpretation of experimental result to fit in
> your "choice"?
You can complain about twisting the results themselves but the
interpretation of the results is our free choice.
> I mean MMX null result, stellar aberration can be explained other way.
I know, the so called LET is a perfectly good way to explain all
SR results.
Martin Hogbin
Joe Fischer
: There is no logic in opting for a theory where the speed of light is
: reason why it should be.
There is when every measurement of the speed
of light, made 10 different ways, always gives the
same result.
: Read again Einstein's justification above. It
: doesn't make sense. It is flawed logic. As you say it was not easy to
: go back and *anything* was easier to accept than admitting they had been
: wrong for 200 years. Abandoning universal time etc. etc. was the price
: they were willing to pay to preserve their beliefs. That is what I mean
: when I refer to its dodgy origins.
What is "universal time"? If you mean
that time must flow at the same rate everywhere in
the universe, it does, and it actually does so in
General Relativity, the many interpretations are
often partially wrong.
: See above. I don't believe that Einstein ever completely rejected the
: concept of the aether.
Then you haven't read many of the hundreds
of papers he wrote.
: He is reported as saying "... we have not proven
: that the Aether does not exist, we have only proven that we do not need
: it (for calculations)".
Because he was smart enough to know that
proving something does not exist is impossible.
In the "complete papers" volumes you can
find many papers which touch on the issue of an
ether being needed or existing.
No practicing physicist today would even
spend one minute thinking about the existence of
an aether, he needs to spend all his time on things
he can see, measure, feel, hear, touch.
Joe Fischer
--
3
Martin Hogbin
"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message news:jbGQynCU...@kennaugh.demon.co.uk...
> Martin Hogbin writes
> >
> >"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message
> >news:FqnJuLGR...@kennaugh.demon.co.uk...
> >> In message <auhao7$j13$1...@venus.btinternet.com>, Martin Hogbin
> >> <sp...@hogbin.org> writes
> >> >
> >> >"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message
> >>
> >> >This is, to say the least, a rather idiosyncratic description of relativity.
> I am talking about a decision made at a particular point in history and
> the thinking behind it.
Fine, the reasoning behind physicists' decisions is an interesting subject in
its own right but the OP asked for a mainstream explanation and you
put your comments under a sub-heading of 'relativity'. The OP
therefore has a right to expect a modern mainstream explanation.
>
> In Maxwell's equations
> c is the speed of propagation of the electromagnetic disturbance in
> Maxwell's aether.
There has been much pointless discussion of this subject on
another thread. Maxwell's equations give rise to an answer,
in terms of a speed, to an unknown question.
>When MM disproved the universal aether, Einstein
> postulated that the speed of light is constant w.r.t the observer. As c
> is the speed of propagation in Maxwell's aether, then unless you throw
> out Maxwell's equations, saying c is constant w.r.t the observer, is
> mathematically the same as saying the observer is stationary w.r.t
> Maxwell's aether.
Maxwell's equations and Maxwell's concept of an aether
are not the same thing. His equations stand in their own right,
with or without the aether.
> In a book co-authored by Einstein called "The Evolution of Physics" the
> argument went as follows:
<snip>
I have no idea whether your summary of this book is correct but I do
not see what point you are making. Your view on the thought train
that led Einstein to his theory is of little interest to most people.
------------------------------------------------------------
> >in fact one of the main points of relativity is that a
> >medium is not required at all.
>
> However if you refer to the book quoted above Einstein says "it is a
> strange but indisputable fact". He was using the word 'postulate' in
> accordance with the alternative dictionary definition as 'a self evident
> truth' something he didn't have to prove because everyone accepted it to
> be the case.
I am not sure what your complaint is here. Is it that Einstein
had no right to postulate what he did?
------------------------------------------------------------
> >
> >Why must it be either? Light is light.
>
> Light is a real physical phenomena which requires a real physical means
> of getting from source to destination. The two possibilities I have
> outlined are all I can see. That may be a limitation in my perception.
I think that it is. By 'real physical means' you seem to mean
'using a concept with which I am already familiar'.
> If you have a third alternative I am perfectly happy to consider it.
> "Light gets from A to B by hitching a lift on a postulate" does not
> appeal I am afraid. Neither does "it gets from A to B by obeying a
> differential equation".
How about just 'light gets from A to B'.
> >Newton's corpuscles were classical objects that would be
> >expected to obey the laws of classical mechanics. They
> >would have locations and trajectories just like any other
> >classical object.
> >
> >With a photon you must forget many of the classical notions.
> >A photon does not have a trajectory or a position. It does
> >however carry momentum.
>
> Again I am talking about a decision made at a particular point in
> history and the thinking behind it. You are confusing modern thinking
> with the thinking which contributed to the decision. At the time it had
> been discovered that light was in discreet lumps. Most unwavelike and
> made to measure for the ballistic theory. As for Photons not having a
> trajectory nor a position - they go from source to destination in a
> straight line and arrive at a specific time which can be detected.
There is no justification for saying that photons goes from A to B in
in a straight line.
>
> >
> > Physicists thought they had got it cracked. Light was an EM wave
> >that travelled at a fixed speed through the rigid aether. But, as you say,
> >the MMX disproved this.
> >
> >My point was that, because of Maxwell's equations and interference
> >phenomena, it was not easy to go back to regarding light as a classical
> >(the only kind they had then) particle.
>
> 'it was not easy to go back' = dogma.
No. Maxwell's equations and interference did not disappear because of
the MMX.
> The wave theory had seemed a
> better option than the corpuscular theory *because* of the hypothesis of
> the universal aether. Post MM the theory they believed in had been left
> with no invisible means of support and the photon had been discovered.
> Logically where else was there to go other than the alternative they had
> rejected? Headlines - "Wave theory scuppered, corpuscular theory
> vindicated".
If you had been the writer of the headlines of the day you would have
been perfectly entitled to write that. Mind you, a few years later you
would have had to have written 'Corpuscular theory scuppered. Help!'
> There is no logic in opting for a theory where the speed of light is
> constant w.r.t the observer when there is absolutely no conceivable
> reason why it should be. Read again Einstein's justification above. It
> doesn't make sense. It is flawed logic.
It was Einstein's postulate
> As you say it was not easy to
> go back and *anything* was easier to accept than admitting they had been
> wrong for 200 years. Abandoning universal time etc. etc. was the price
> they were willing to pay to preserve their beliefs. That is what I mean
> when I refer to its dodgy origins.
What you seem to mean to me is that you do not like your own
particular interpretation of the thought processes that led
Einstein to his theory.
---------------------------------------------------------------------------
> >>Einstein took Maxwell's Aether and decided it was stationary w.r.t
> >> the observer.
> >
> >Einstein took Maxwell's aether and decided it was unnecessary.
>
> [Einstein] is reported as saying "... we have not proven
> that the Aether does not exist, we have only proven that we do not need
> it (for calculations)".
That is why I used the word 'unnecessary'.
John Kennaugh
<grav...@shell1.iglou.com> writes
>John Kennaugh <jo...@kennaugh.demon.co.uk> wrote:
>: There is no logic in opting for a theory where the speed of light is
>: constant w.r.t the observer when there is absolutely no conceivable
>: reason why it should be.
>
> There is when every measurement of the speed
>of light, made 10 different ways, always gives the
>same result.
>
All such measurements were at that time made between a source and a
detector a fixed distance apart. MM had shown that the speed was not
effected by the space between so the speed must be constant w.r.t either
the source or the observer. Such apparatus could not distinguish which.
The source is emitting the light so one can see that it could control
the speed it is emitted at, but how can an observer in any way effect
the light before it reaches him? The idea that he can is very silly.
If they had been forced to consider it because of experimental evidence
which had ruled out all sane alternatives then I would be happy, or at
least happier. That was not the case.
Pre MM light was an electromagnetic disturbance in the aether but you
cannot continue to argue (as AE does) that the speed of light cannot be
effected by the speed of the source because it is constant w.r.t the
medium when MM had just demonstrated that it wasn't. The belief survived
the MM experiment when it had no right to do so.
--
John Kennaugh
Joe Fischer
:Joe Fischer <grav...@shell1.iglou.com> writes
:>John Kennaugh <jo...@kennaugh.demon.co.uk> wrote:
:>: There is no logic in opting for a theory where the speed of light is
:>: constant w.r.t the observer when there is absolutely no conceivable
:>: reason why it should be.
:>
:> There is when every measurement of the speed
:>of light, made 10 different ways, always gives the
:>same result.
:
: All such measurements were at that time made between a source and a
: detector a fixed distance apart.
My statement was about measurements of the
speed of light, and the MMX was not primarily
about measuring the speed of light.
How is your knowledge of astronomy history?
: MM had shown that the speed was not
: effected by the space between so the speed must be constant w.r.t either
: the source or the observer. Such apparatus could not distinguish which.
Nonsense, the speed of light is simply always
measured as c, no matter how, when or where.
That simply means that c is a function of
the length of the meter, or any other standard
unit of length measure, and the length of the
second.
Nothing else can be assumed, and space
or distance really has little to do with it.
: The source is emitting the light so one can see that it could control
: the speed it is emitted at, but how can an observer in any way effect
: the light before it reaches him? The idea that he can is very silly.
Right, and the idea that the motion of the source
could affect the speed it is emitted at is equally silly.
: If they had been forced to consider it because of experimental evidence
: which had ruled out all sane alternatives then I would be happy, or at
: least happier. That was not the case.
Now you want natural physical processes to
conform to your impression of "sane"?
: Pre MM light was an electromagnetic disturbance in the aether but you
: cannot continue to argue (as AE does) that the speed of light cannot be
: effected by the speed of the source because it is constant w.r.t the
: medium when MM had just demonstrated that it wasn't. The belief survived
: the MM experiment when it had no right to do so.
There is no medium, perhaps you can get
more agreeable discussion in the aether newsgroups.
Frankly, I don't even know what you mean
by "speed of the source", it is only your concepts
of space and aether that produce such nonsensical
statements.
If the speed of light was not measured as
a constant, the spectrum would be totally screwed up,
we would not be able to even use it as a scientific
tool for astronomical objects.
The fact that the spectrum can be used as a
tool is evidence that the speed of light is always
measured as c, even without making a measurement
of speed.
Joe Fischer
--
3
John Kennaugh
>>
>> In Maxwell's equations
>> c is the speed of propagation of the electromagnetic disturbance in
>> Maxwell's aether.
>
>There has been much pointless discussion of this subject on
>another thread. Maxwell's equations give rise to an answer,
>in terms of a speed, to an unknown question.
I think I would go along with that. It doesn't stop people claiming that
Maxwell's equations ruled out the ballistic theory on the grounds that
it shows the speed of light is c which is independent of the speed of
the source. It is independent of the speed of the observer also but that
doesn't seem to bother them.
Einstein used a similar argument ".... he could think of no form of
differential equation which could have solutions representing waves
whose velocity depended on the motion of the source".
>
>> In a book co-authored by Einstein called "The Evolution of Physics" the
>> argument went as follows:
><snip>
>
>I have no idea whether your summary of this book is correct but I do
>not see what point you are making. Your view on the thought train
>that led Einstein to his theory is of little interest to most people.
I believe that my summery is accurate. You are free to speak for
yourself but not for others. Surely anyone in Physics is interested in
where the idea came from and the fact that AE was capable of seriously
dodgy thinking is worrying. Many of course dare not think the
unthinkable.
>------------------------------------------------------------
>> >
>> >Why must it be either? Light is light.
>>
>> Light is a real physical phenomena which requires a real physical means
>> of getting from source to destination. The two possibilities I have
>> outlined are all I can see. That may be a limitation in my perception.
>
>I think that it is. By 'real physical means' you seem to mean
>'using a concept with which I am already familiar'.
>
>> If you have a third alternative I am perfectly happy to consider it.
>> "Light gets from A to B by hitching a lift on a postulate" does not
>> appeal I am afraid. Neither does "it gets from A to B by obeying a
>> differential equation".
>
>How about just 'light gets from A to B'.
If you just accept that things happen without asking why or how surly
you have removed the need for science. Plants just grow! Volcanos just
erupt.
>> As for Photons not having a
>> trajectory nor a position - they go from source to destination in a
>> straight line and arrive at a specific time which can be detected.
>
>There is no justification for saying that photons goes from A to B in
>in a straight line.
It is a justifiable assumption unless there is definite evidence to the
contrary. Light travels in straight lines, light is made up of photons
so photons must travel in a straight line. Or alternatively if
there is nothing by way of a medium in a vacuum which can effect the
motion of light what could possible cause a photon to change direction.
>
>> The wave theory had seemed a
>> better option than the corpuscular theory *because* of the hypothesis of
>> the universal aether. Post MM the theory they believed in had been left
>> with no invisible means of support and the photon had been discovered.
>> Logically where else was there to go other than the alternative they had
>> rejected? Headlines - "Wave theory scuppered, corpuscular theory
>> vindicated".
>
>If you had been the writer of the headlines of the day you would have
>been perfectly entitled to write that.
That is the essence of the point I was making.
> Mind you, a few years later you
>would have had to have written 'Corpuscular theory scuppered. Help!'
When do you think that would be I wonder? de Sitter perhaps?
Let us hypothesise that in a parallel universe my headline did in fact
appear and that sufficient time elapsed for the Ballistic theory to be
established before de Sitter. Anything which seemed to undermine
established theory would have been treated with the same lack of
objectivity as normally shown. The evidence interpreted in terms of the
theory which existed and subject to hostile scrutiny. It probably
wouldn't even get published because of the referee system or at least
until every possible objection had been addressed to the nth degree. If
it ever emerged from obscurity I think the headlines would go:
Ballistic Theory under Scrutiny?
================================
"In an interview Professor A.N.Other, the leading authority on light
phenomena stated that it was an interesting result worthy of further
study but that he attached no great significance to it. When asked to
comment on the claim that it supported the alternative, so called
'Relativity' theory Prof.Other stated "That is a daft theory thought up
by a German Patent clerk which appeals to a small number of crackpots
who are unable to accept that the wave theory was dead. Its starting
premise is not supported by experiment, it has no real theoretical basis
and bears no relationship to reality whatsoever. It cannot even give a
reasonable explanation of Doppler shift. If you switch a light on it
requires it to come on at different times and the light to travel from
it at different speeds for each and every observer. I don't think we are
ready to abandon real science and launch ourselves into the realms of
pseudo science just because we do not have an immediate explanation for
an obscure bit of research based on rather fuzzy data."
Happy New Year in this universe.
--
John Kennaugh
John Kennaugh
>John Kennaugh <jo...@kennaugh.demon.co.uk> wrote:
>:Joe Fischer <grav...@shell1.iglou.com> writes
>:>John Kennaugh <jo...@kennaugh.demon.co.uk> wrote:
>:>: There is no logic in opting for a theory where the speed of light is
>:>: constant w.r.t the observer when there is absolutely no conceivable
>:>: reason why it should be.
>:>
>:> There is when every measurement of the speed
>:>of light, made 10 different ways, always gives the
>:>same result.
>:
>: All such measurements were at that time made between a source and a
>: detector a fixed distance apart.
>
> My statement was about measurements of the
>speed of light, and the MMX was not primarily
>about measuring the speed of light.
>
> How is your knowledge of astronomy history?
My knowledge of astronomy history is not that detailed although I am
aware that James Bradley 1728 got the first really accurate value for
the speed of light by assuming that the speed of light was c+v. May I
remind you that I am talking about a decision made at a particular point
in time. I am not aware of any measurements of the speed of light from a
moving source prior to that which would justify your claim. Maybe you
would care to enlighten me?
>: The source is emitting the light so one can see that it could control
>: the speed it is emitted at, but how can an observer in any way effect
>: the light before it reaches him? The idea that he can is very silly.
>
> Right, and the idea that the motion of the source
>could affect the speed it is emitted at is equally silly.
>
No it isn't. If a gun shoots a bullet, it, and nothing else, will effect
the speed of the bullet. If a source emits a photon it not silly to
suppose that it can determine the speed at which it leaves the source.
Perfectly sensible in fact.
>: If they had been forced to consider it because of experimental evidence
>: which had ruled out all sane alternatives then I would be happy, or at
>: least happier. That was not the case.
>
> Now you want natural physical processes to
>conform to your impression of "sane"?
No I require normal scientific method. Consider all alternatives chose
the simplest explanation first and do not progress to the more elaborate
ones until the simplest has been disproved.
>
>: Pre MM light was an electromagnetic disturbance in the aether but you
>: cannot continue to argue (as AE does) that the speed of light cannot be
>: effected by the speed of the source because it is constant w.r.t the
>: medium when MM had just demonstrated that it wasn't. The belief survived
>: the MM experiment when it had no right to do so.
>
> There is no medium, perhaps you can get
>more agreeable discussion in the aether newsgroups.
You should try reading a posting before commenting on it. I would be the
last person to argue that there is an aether. Einstein dismissed the
ballistic theory on the grounds that the speed of light could not be
effected by the speed of the source because it was constant w.r.t the
aether. There is no aether/medium. I agree. Therefore Einstein's reason
for rejecting the ballistic theory was invalid.
> If the speed of light was not measured as
>a constant, the spectrum would be totally screwed up,
>we would not be able to even use it as a scientific
>tool for astronomical objects.
>
> The fact that the spectrum can be used as a
>tool is evidence that the speed of light is always
>measured as c, even without making a measurement
>of speed.
OK you are into astronomy. Something I raised in this NG. The Universe
is about 15 billion years old. Astronomers claim to be able to see back
to say 1 billion years after the big bang. My question was - In order to
see that far back the source must be 14 billion light years away from us
and yet had only 1 billion years since the big bang to get there = a
separation velocity = 14c. No I was told. I had forgotten about time
dilation. Because it is travelling away from us at nearly the speed of
light it doesn't age as quickly as we do so we see it as much younger
than one might expect. So I did the sums:
------------------------------------------------------
The story according to relativity
=================================
If the universe started at time 0
If the Age of the Universe is Tau
If we and a Far Galaxy have been separating at speed v
and light has just reached us which left at time T
Then we were separated by distance vT when the light left.
It has been travelling for (Tau - T) at speed c.
so vT = c(Tau-T) = cTau - cT
T(c+v) = c.Tau
T = c.Tau/(c+v)
However due to time dilation the age we observe will be
Age = T.sqr(1-vv/cc) = [c.Tau/(c+v)].sqr(1-vv/cc)
Suppose we take Tau = 15x10^9
Age we see of Far Galaxy = (15.c/c+v).sqr(1-vv/cc) billion years
if say v = 0.900c then Age = 3.441236 billion years
----------------------------------------------------------------
Now we cannot directly measure the speed of a receding galaxy we
calculate its speed using Doppler.
The relativistic Doppler equation for a receding source is
fo = fs. sqr(1-vv/cc)/(1+v/c)
If in the above analysis v was calculated from the relativistic Doppler
equation then 0.9c resulted from a Doppler shift fo/fs = 0.2294157.
The Ballistic Doppler shift equation is much simpler than the
Relativistic one:
fo = fs((c-v)/c)
That same Doppler shift would be interpreted by the Ballistic theory as
v = 0.770584266c
------------------------------------------------------------------------
The story According to the Ballistic theory
===========================================
The Ballistic explanation is that if the far galaxy is travelling away
from us at near c then its light takes longer to travel to us because it
is only travelling at c-v relative to us. Note that the limiting factor
of both theories when v = c we see time zero. Relativity - because time
stops. Ballistic because our relative velocity to the light image is
zero.
If the universe started at time 0
If the age of the universe is Tau
If we and a Far Galaxy have been separating at speed v
and light has just reached us which left FG at time T
Then we were separated by distance vT when it left.
It has been travelling for (Tau - T) at speed c-v.
so vT = (c-v)(Tau-T)
T(v/(c-v)) = Tau - T
T( v/(c-v) + 1 ) = Tau
T( c/(c-v)) = Tau
T = Tau.(c-v)/c
Age seen of Far Galaxy = 15 (c-v)/c billion years
Now for the same Doppler shift we calculated v = 0.770584266c
and we calculate the Age of the Far Galaxy as 3.441236 billion years.
Compared to the value from Relativity of 3.441236 billion years.
---------------------------------------------------------------------
So whether you do the calculation using Relativity or using the
ballistic theory, far from screwing things up you end up with exactly
the same result. Compare the complexity of the equations:
Relativity Ballistic
Age (Tau.c/c+v).sqr(1-vv/cc) Tau(c-v)/c
Doppler sqr(1-vv/cc)/(1+v/c) (c-v)/c)
I did the sums out of curiosity but the result was not unexpected. The
ballistic theory usually does give the same result. The explanation
behind the maths differs. Relativity requires time dilation to explain
the result the ballistic theory requires nothing out of the ordinary.
Your comment implies that you have been taken in by propaganda.
--
John Kennaugh
Stephen Speicher
> Martin Hogbin writes
> >
> >"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message
> >news:jbGQynCU...@kennaugh.demon.co.uk...
> >
> >> In a book co-authored by Einstein called "The Evolution of Physics" the
> >> argument went as follows:
> ><snip>
> >
> >I have no idea whether your summary of this book is correct but I do
> >not see what point you are making. Your view on the thought train
> >that led Einstein to his theory is of little interest to most people.
>
> I believe that my summery is accurate. You are free to speak for
> yourself but not for others. Surely anyone in Physics is interested in
> where the idea came from and the fact that AE was capable of seriously
> dodgy thinking is worrying. Many of course dare not think the
> unthinkable.
I have not seen your "summery [sic]," but if taken from this book
then it is not valid. I have written about this many times: "The
Evolution of Physics" was written entirely by Leopold Infeld, and
Einstein lent his name to the book in order to keep Infeld, a
Jew, from being sent back to Poland. It is not valid to use any
quotations from that book unless the same idea is explicitly
echoed in material we know that Einstein actually wrote,
elsewhere.
--
Stephen
s...@speicher.com
Ignorance is just a placeholder for knowledge.
Printed using 100% recycled electrons.
-----------------------------------------------------------
John Kennaugh
<Pine.LNX.4.33.030102...@localhost.localdomain>,
Stephen Speicher <s...@speicher.com> writes
>On Thu, 2 Jan 2003, John Kennaugh wrote:
>
>> Martin Hogbin writes
>> >
>> >"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message
>> >news:jbGQynCU...@kennaugh.demon.co.uk...
>> >
>> >> In a book co-authored by Einstein called "The Evolution of Physics" the
>> >> argument went as follows:
>> ><snip>
>> >
>> >I have no idea whether your summary of this book is correct but I do
>> >not see what point you are making. Your view on the thought train
>> >that led Einstein to his theory is of little interest to most people.
>>
>> I believe that my summery is accurate. You are free to speak for
>> yourself but not for others. Surely anyone in Physics is interested in
>> where the idea came from and the fact that AE was capable of seriously
>> dodgy thinking is worrying. Many of course dare not think the
>> unthinkable.
>
>I have not seen your "summery [sic],"
I no longer have the book so I cannot check the actual wording. My
summery was:
1/ Light is a propagated wave propagated by a medium called the Aether.
The velocity of a wave is a function of the medium which propagates it
and its velocity can only be effected by the source if the movement of
the source causes movement of the medium. Aether drag experiments,
passing light close to heavy rotating flywheels has shown that they had
no effect on the light passing close to them hence the speed of light
cannot be effected by the speed of the source.
2/ Although the speed of light might be expected to vary with the speed
of the observer Michelson and Morley had shown that not to be the case
so it is a strange but indisputable fact that the velocity of light is
constant independent of the velocity of the source or the observer.
>but if taken from this book
>then it is not valid. I have written about this many times: "The
>Evolution of Physics" was written entirely by Leopold Infeld, and
>Einstein lent his name to the book in order to keep Infeld, a
>Jew, from being sent back to Poland. It is not valid to use any
>quotations from that book unless the same idea is explicitly
>echoed in material we know that Einstein actually wrote,
>elsewhere.
>
I assumed that having put his name to the book that Einstein would have
written the relevant bit on relativity if he contributed nothing else or
at the very least read and approved it. It was not an unreasonable
assumption, but I accept that it might be wrong in the extreme
circumstances which you describe.
Maybe you are in a position to quote Einstein directly. I am most
interested in his earliest thoughts on the subject. What his starting
point was. What led him to formulate his 2nd postulate and why he
rejected the Ballistic/emission theory. The technique used in the
average text book goes like this.
Chapter on MM concludes with a statement
"...... and thus it was shown that the speed of light is always found to
be constant independent of the motion of the observer." Which IN CONTEXT
is not untrue. There is then a good bit of text dealing with other
things so that the context of the statement is forgotten before you get
to the chapter on relativity. Here an almost identical statement is
found "As it was shown that the speed of light is always found to be
constant independent of the motion of the observer." this time it is
used to mean "... found to be constant independent of the motion of the
observer [relative to the source]." - and straight into relativity.
While the statement in the MM chapter is not untrue taken in context. If
you add the assumptions inherent in the context it should say:
"...... and thus it was shown that the speed of light, when measured
between a source and detector a fixed distance apart, is constant
independent of the motion of the observer/apparatus w.r.t the rest of
the universe." It can say nothing about the situation where there is
relative motion between source and observer. There was none.
I was a student more than 40 years ago. I do not understand why every
student hasn't spotted the same bit of deception and shouted 'foul'. At
the time I assumed I had a third rate text book but most text books use
the same ploy. The only text book which tried to justify it is the one
quoted above and as far as I am concerned it is twaddle whoever wrote it
but I suspect it is extremely close to the actual thinking of the day.
1/ The speed of light cannot be effected by the source - statement of
universal faith/dogma despite the fact that the justification for such
faith had been totally demolished.
2/ MM showed it isn't constant w.r.t the universal aether.
3/ That leaves 'constant w.r.t the observer'. - silly though it may
seem.
If I was writing a physics text book today I still do not know of a
legitimate way of bridging the gap between MM and relativity and I have
been looking for more than 40 years.
--
John Kennaugh
John C. Polasek
Minkowski's expression for velocity is V = v + ic, is it not? Let v be
the composite velocity vector we can measure. ic is permanently,
monotonously, irrevocably, unarguably at right angles to any velocity
you can name, by virtue of the i in ic.
Therefore the MM experiment had no hope of finding an ether drift. But
the v + ic thing was not known in 1887. And after 1905, apparently it
has not been back-applied to the MM experiment. The MM experiment was
based on some v + c arithmetic, which is now replaced by v + ic.
Rotate v in any direction you please as Michelson did, and nothing
happens. Hence my claim that c is "not one of our velocities".
Mr. Dual Space
(If you have something to say, write an equation.
If you have nothing to say, write an essay).
Martin Hogbin
"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message news:h1lwJjEA...@kennaugh.demon.co.uk...
> Martin Hogbin writes
>
> Surely anyone in Physics is interested in
> where the idea came from and the fact that AE was capable of seriously
> dodgy thinking is worrying. Many of course dare not think the
> unthinkable.
You may chose to think of Einstein as a lucky chancer, others
may call him an inspired genius but nobody does it by logic alone.
He did , however, present his theory properly in that he did
not claim that the constancy of light speed was a proven fact,
he quite correctly put it forward as a postulate.
------------------------------------------------------------
I have deleted the bit about photons as this is really a QM issue.
We can discuss it on another thread if you want.
----------------------------------------------------------------
> Let us hypothesise that in a parallel universe my headline did in fact
> appear and that sufficient time elapsed for the Ballistic theory to be
> established before de Sitter.
That would not be so easy. The ballistic theory already had several
problems. How does light speed up after passing through a
glass block into air.
How would it explain the results of Fresnel?
> Anything which seemed to undermine
> established theory would have been treated with the same lack of
> objectivity as normally shown.
Shown where, and by whom?
> The evidence interpreted in terms of the
> theory which existed and subject to hostile scrutiny.
Scrutiny, of course. Hostile, no.
> It probably
> wouldn't even get published because of the referee system or at least
> until every possible objection had been addressed to the nth degree.
Like the MMX was not published?
> If it ever emerged from obscurity I think the headlines would go:
> Ballistic Theory under Scrutiny?
> ================================
> "In an interview Professor A.N.Other, the leading authority on light
> phenomena stated that it was an interesting result worthy of further
> study but that he attached no great significance to it. When asked to
> comment on the claim that it supported the alternative, so called
> 'Relativity' theory Prof.Other stated "That is a daft theory thought up
> by a German Patent clerk which appeals to a small number of crackpots
> who are unable to accept that the wave theory was dead. Its starting
> premise is not supported by experiment, it has no real theoretical basis
> and bears no relationship to reality whatsoever.
What experiment do you claim does not support SR.?
> It cannot even give a
> reasonable explanation of Doppler shift.
Why do you say this?
> If you switch a light on it
> requires it to come on at different times and the light to travel from
> it at different speeds for each and every observer. I don't think we are
> ready to abandon real science and launch ourselves into the realms of
> pseudo science just because we do not have an immediate explanation for
> an obscure bit of research based on rather fuzzy data."
I that these are the words of an imagined professor who was supporting
the ballistic theory but I have a sneaking suspicion that you believe some of it.
Martin Hogbin
Martin Hogbin
"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message news:h1lwJjEA...@kennaugh.demon.co.uk...
> Martin Hogbin writes
>
> Surely anyone in Physics is interested in
> where the idea came from and the fact that AE was capable of seriously
> dodgy thinking is worrying. Many of course dare not think the
> unthinkable.
You may chose to think of Einstein as a lucky chancer, others
may call him an inspired genius but nobody does it by logic alone.
He did , however, present his theory properly in that he did
not claim that the constancy of light speed was a proven fact,
he quite correctly put it forward as a postulate.
------------------------------------------------------------
I have deleted the bit about photons as this is really a QM issue.
We can discuss it on another thread if you want.
----------------------------------------------------------------
> Let us hypothesise that in a parallel universe my headline did in fact
> appear and that sufficient time elapsed for the Ballistic theory to be
> established before de Sitter.
That would not be so easy. The ballistic theory already had several
problems. How does light speed up after passing through a
glass block into air.
How would it explain the results of Fresnel?
> Anything which seemed to undermine
> established theory would have been treated with the same lack of
> objectivity as normally shown.
Shown where, and by whom?
> The evidence interpreted in terms of the
> theory which existed and subject to hostile scrutiny.
Scrutiny, of course. Hostile, no.
> It probably
> wouldn't even get published because of the referee system or at least
> until every possible objection had been addressed to the nth degree.
Like the MMX was not published?
> If it ever emerged from obscurity I think the headlines would go:
> Ballistic Theory under Scrutiny?
> ================================
> "In an interview Professor A.N.Other, the leading authority on light
> phenomena stated that it was an interesting result worthy of further
> study but that he attached no great significance to it. When asked to
> comment on the claim that it supported the alternative, so called
> 'Relativity' theory Prof.Other stated "That is a daft theory thought up
> by a German Patent clerk which appeals to a small number of crackpots
> who are unable to accept that the wave theory was dead. Its starting
> premise is not supported by experiment, it has no real theoretical basis
> and bears no relationship to reality whatsoever.
What experiment do you claim does not support SR.?
> It cannot even give a
> reasonable explanation of Doppler shift.
Why do you say this?
> If you switch a light on it
> requires it to come on at different times and the light to travel from
> it at different speeds for each and every observer. I don't think we are
> ready to abandon real science and launch ourselves into the realms of
> pseudo science just because we do not have an immediate explanation for
> an obscure bit of research based on rather fuzzy data."
I that these are the words of an imagined professor who was supporting
Stephen Speicher
> In message
> <Pine.LNX.4.33.030102...@localhost.localdomain>,
> Stephen Speicher <s...@speicher.com> writes
> >On Thu, 2 Jan 2003, John Kennaugh wrote:
> >
> >> Martin Hogbin writes
> >> >
> >> >"John Kennaugh" <jo...@kennaugh.demon.co.uk> wrote in message
> >> >news:jbGQynCU...@kennaugh.demon.co.uk...
> >> >
> >> >> In a book co-authored by Einstein called "The Evolution of Physics" the
> >> >> argument went as follows:
> >> ><snip>
> >> >
> >> >I have no idea whether your summary of this book is correct but I do
> >> >not see what point you are making. Your view on the thought train
> >> >that led Einstein to his theory is of little interest to most people.
> >>
> >> I believe that my summery is accurate. You are free to speak for
> >> yourself but not for others. Surely anyone in Physics is interested in
> >> where the idea came from and the fact that AE was capable of seriously
> >> dodgy thinking is worrying. Many of course dare not think the
> >> unthinkable.
> >
> >I have not seen your "summery [sic]," but if taken from this
> >book then it is not valid. I have written about this many
> >times: "The Evolution of Physics" was written entirely by
> >Leopold Infeld, and Einstein lent his name to the book in
> >order to keep Infeld, a Jew, from being sent back to Poland.
> >It is not valid to use any quotations from that book unless
> >the same idea is explicitly echoed in material we know that
> >Einstein actually wrote, elsewhere.
> >
>
> I assumed that having put his name to the book that Einstein would have
> written the relevant bit on relativity if he contributed nothing else or
> at the very least read and approved it. It was not an unreasonable
> assumption, but I accept that it might be wrong in the extreme
> circumstances which you describe.
>
You did make a reasonable assumption -- I was not criticizing you
for that -- but if you accept what I say then you should not
continue to use material from that book as being Einstein's
formulations, unless corroborated by actual writings by Einstein,
elsewhere.
> Maybe you are in a position to quote Einstein directly. I am most
> interested in his earliest thoughts on the subject. What his starting
> point was. What led him to formulate his 2nd postulate and why he
> rejected the Ballistic/emission theory. The technique used in the
> average text book goes like this.
>
These are very interesting issues -- all of which I have
discussed before -- but I will make this very short, without
references. I will ignore the emission theory issue directly,
because I discussed this with you previously in regard to Ritz,
and, as I recall, you seemed to have some difficulty following
along. I have no time now for prolonged and difficult
discussions.
As to Einstein's starting point: it depends upon what you mean by
that term. Einstein credits the null result of the
Michelson-Morley experiment as "the first path which led me to
the special theory of relativity." As a student Einstein
discovered the MMX and he realized that "our idea about the
motion of the earth with respect to the ether is incorrect." On
the other hand, Einstein credits his "direct path to the special
theory of relativity" was via the phenomena of electromagnetic
induction, and it was this which led to the first postulate.
As to the second postulate: Einstein always used the MMX as
support for the first postulate, not the second postulate.
Briefly, building on the Fitzeau experiment, and aberration,
Einstein found great value in what was known as the
Maxwell-Lorentz electromagnetic theory (Lorentz in 1895), except
that it did not integrate with the principle of relativity, and
he saw the contraction hypothesis as being quite ad hoc. He
understood the constancy of c required of Maxwell's equations,
and found no reasonable approach towards an electromagnetic
theory based on an emission hypothesis. Einstein realized that he
needed to modify Lorentz' approach to resolve the incompatibilty
of the principle of relativity with the constancy of light, which
after great struggle he resolved through the issue of relativity
of simultaneity.
John Kennaugh
>> Martin Hogbin writes
>>
>> Surely anyone in Physics is interested in
>> where the idea came from and the fact that AE was capable of seriously
>> dodgy thinking is worrying. Many of course dare not think the
>> unthinkable.
>
>You may chose to think of Einstein as a lucky chancer, others
>may call him an inspired genius but nobody does it by logic alone.
>
>He did , however, present his theory properly in that he did
>not claim that the constancy of light speed was a proven fact,
>he quite correctly put it forward as a postulate.
>
Assuming Stephen Speicher is correct I was making a false assumption in
that regard.
>------------------------------------------------------------
>I have deleted the bit about photons as this is really a QM issue.
>We can discuss it on another thread if you want.
>----------------------------------------------------------------
>
>> Let us hypothesise that in a parallel universe my headline did in fact
>> appear and that sufficient time elapsed for the Ballistic theory to be
>> established before de Sitter.
>
>That would not be so easy. The ballistic theory already had several
>problems. How does light speed up after passing through a
>glass block into air.
You are applying double standards. The 'postulate' on which the
Ballistic theory would be based is that c is the natural speed at which
light is emitted/ejected from a solid into vacuum. The glass acts the
same as any other source in that respect. As it is a 'postulate' it does
not need to be justified.
From my point of view relativity 'has several problems' one is 'why is
the speed of light constant w.r.t the observers frame of reference'
another is 'how does light get from A to B'. Your suggestion for the
latter was:
"How about just 'light gets from A to B'".
Fine - How about just 'light leaves glass at c'
Once relativity had been accepted the tendency has been to introduce
whatever degree of 'flexible thinking' is necessary to keep it
acceptable. If the Ballistic theory had been accepted would the degree
of flexibility required to keep it acceptable be any greater than that
demanded by relativity?
>
>How would it explain the results of Fresnel?
>
I don't think it would be too difficult. 'Provided you don't insist that
it must be explained in terms of everyday concepts'. I will give you a
chance to pull my ideas to shreds at a later date.
>> Anything which seemed to undermine
>> established theory would have been treated with the same lack of
>> objectivity as normally shown.
>
>Shown where, and by whom?
There is a long history of Science not being objective because of deeply
held belief. The classical example is the total rejection of continental
drift by the geological community. The idea was ridiculed. It has now
spawned a new science but it would still be gathering dust if it had
been left to the geologists. There are many examples a lot nearer home
but you and I would probably not see them the same.
>
>> The evidence interpreted in terms of the
>> theory which existed and subject to hostile scrutiny.
>Scrutiny, of course. Hostile, no.
>> It probably
>> wouldn't even get published because of the referee system or at least
>> until every possible objection had been addressed to the nth degree.
>Like the MMX was not published?
I don't think they had invented the referee system then.
>> If it ever emerged from obscurity I think the headlines would go:
>
>> Ballistic Theory under Scrutiny?
>> ================================
>> "In an interview Professor A.N.Other, the leading authority on light
>> phenomena stated that it was an interesting result worthy of further
>> study but that he attached no great significance to it. When asked to
>> comment on the claim that it supported the alternative, so called
>> 'Relativity' theory Prof.Other stated "That is a daft theory thought up
>> by a German Patent clerk which appeals to a small number of crackpots
>> who are unable to accept that the wave theory was dead. Its starting
>> premise is not supported by experiment, it has no real theoretical basis
>> and bears no relationship to reality whatsoever.
>
>What experiment do you claim does not support SR.?
>
I said its starting *premise* is not supported by experiment. To quote
you:
>he did
>not claim that the constancy of light speed was a proven fact,
>> It cannot even give a
>> reasonable explanation of Doppler shift.
>
>Why do you say this?
>
Because I have never seen a text book description. They usually talk
about train whistles and say that similar principles apply!!!!. I came
up with my own:
The same light leaves the same source at both c and c+v in order to
travel to two observers 'A' stationary and 'B' moving away from the
source. 'A' cannot see the light travelling to 'B' and 'B' can't see the
light travelling to 'A'. The number of observers is unlimited so the
different speeds at which light leaves the source is unlimited. Despite
the fact that an observer can only see the light travelling at c w.r.t
himself and none other the intensity seen is the same as if he were the
only observer.
Don't tell me, I am trying to explained it in terms of everyday
concepts. What is your version?
>> If you switch a light on it
>> requires it to come on at different times and the light to travel from
>> it at different speeds for each and every observer. I don't think we are
>> ready to abandon real science and launch ourselves into the realms of
>> pseudo science just because we do not have an immediate explanation for
>> an obscure bit of research based on rather fuzzy data."
>
>I that these are the words of an imagined professor who was supporting
>the ballistic theory but I have a sneaking suspicion that you believe
>some of it.
Anyone seriously studying the ballistic theory must conclude that it is
worthy of consideration. It may ultimately come second but it would come
a very close second. Close enough to maybe speculate that in the right
hands it might have/still come first or that if it had been accepted
initially that there is serious doubt that Relativity would have
displaced it.
The reaction I get in bringing up the subject is typified by Joe
Fischer's outburst. He clearly sees nothing wrong in vilifying me
despite the fact he hasn't got a clue about the theory he is attacking.
A not untypical hostile response. He is acting like a 'true believer'
dealing with a 'heretic' confident that whatever the heretic says must
be nonsense.
In my response to him I explored an implication of relativity which has
only recently come to my notice by using the same starting point for
both the relativity and the ballistic theory standpoints. Both gave the
same end result. The ballistic theory gets there with much simpler
equations and a common sense explanation. It doesn't prove anything of
course (apart from saying something about Joe Fisher and his kind) but
it is suggestive I think to those who do not have a closed mind.
I am not a physicist. I am not a teacher of science. I am not a
mathematician. I think for a hobby and have decided to explore one of
the side roads of physics as far as my limited ability will allow. I
hope to broaden the outlook of people like yourself that relativity is
not all there is. I have respect for you in that you have tried to
answer me objectively rather than call me names.
I realised some time ago that the only difference between the ballistic
concept and relativity is the direction of time.
Relativity
A -----> B
Light travels from A to B at speed c constant w.r.t B.
The time = (the distance A to B at the time the light leaves A)/c
independent of the relative speed of A and B.
Ballistic
A <------B
Light travels from B to A at speed c constant w.r.t B.
The time = (the distance A to B at the time the light arrives at A)/c
independent of the relative speed of A and B. See Appendix I
Reversing the direction of time on one (playing the film backwards)
gives the other. It is for that reason I was not surprised that I got
the same result for both theories in my response to Joe Fisher. If both
theories result in the same mathematics (note I did say IF) then one
should ask which theory looks as if time is going backwards. The effect
of time going backwards is that everything would look very strange
compared to every day experience. A very accurate description of
Relativity.
-------------------------------------------------------------------
Appendix I
Ballistic
A <--B Light sets out
A<-----------------B <--v it reaches A
|< d >|< vt >|
Light travels from B at c+v relative to A and reaches A when B
is d away from A.
Thus t = (d + vt)/(c+v)
tc + tv = d + vt
tc = d
t = d/c
--
John Kennaugh
John Kennaugh
<Pine.LNX.4.33.030103...@localhost.localdomain>,
Stephen Speicher <s...@speicher.com> writes
>On Fri, 3 Jan 2003, John Kennaugh wrote:
>
>You did make a reasonable assumption -- I was not criticizing you
>for that -- but if you accept what I say then you should not
>continue to use material from that book as being Einstein's
>formulations, unless corroborated by actual writings by Einstein,
>elsewhere.
>
>> Maybe you are in a position to quote Einstein directly. I am most
>> interested in his earliest thoughts on the subject. What his starting
>> point was. What led him to formulate his 2nd postulate and why he
>> rejected the Ballistic/emission theory. The technique used in the
>> average text book goes like this.
>>
>
>These are very interesting issues -- all of which I have
>discussed before -- but I will make this very short, without
>references. I will ignore the emission theory issue directly,
>because I discussed this with you previously in regard to Ritz,
>and, as I recall, you seemed to have some difficulty following
>along.
I have not had time to follow up the references you gave me but I do not
think you attempted to answer my main point.
<snip bit on first postulate which I am happy follows sensibly from MMX>
>
>As to the second postulate: Einstein always used the MMX as
>support for the first postulate, not the second postulate.
>Briefly, building on the Fitzeau experiment, and aberration,
I interested specifically in why he rejected the ballistic theory. I
don't quite see the relevance of the Fitzeau experiment to SR which is
only about the speed of light in vacuum. James Bradley 1728 got the
first really accurate value for c by assuming star aberration was due to
the vector sum of the speed of light from stars and that of the earth
i.e. the ballistic theory gave the right answer.
>Einstein found great value in what was known as the
>Maxwell-Lorentz electromagnetic theory (Lorentz in 1895), except
>that it did not integrate with the principle of relativity, and
>he saw the contraction hypothesis as being quite ad hoc.
agreed see below.
> He
>understood the constancy of c required of Maxwell's equations,
I beg to differ. He didn't understand it. You quoted Robert Shankland
interview with Einstein Feb 1950.
"[Einstein] could think of no form of differential
equation which could have solutions representing waves
whose velocity depended on the motion of the source. In
this case, the emission theory would lead to phase
relations such that the propagated light would be all
badly "mixed up' and might even 'back up on itself.' He
asked me, 'Do you understand that ?' I said no and he
carefully repeated it all. When he came again to the
'mixed up' part he waved his hands before his face and
laughed, an open hearty laugh at the idea!"
Maxwell believed his equations related to the aether. One particular
solution must be for an observer stationary w.r.t the aether and another
with the source stationary w.r.t the aether. There can be no difference
in difficulty in producing differential equation with solutions
representing waves whose velocity depended on the motion of the source,
or the observer. There is difficulty if it depend on the velocity of the
observer. If there isn't an observer I can't see how the equation can
have a solution. Have I perhaps missed the bit in relativity which says
that light which is not going to be observed cannot be emitted.
While I accept that you may have a valid point regarding the text in
'The Evolution of Physics' what Einstein says in the above interview is
still twaddle. It relates to the same issue, probably the most important
decision in Physics, the rejection of the ballistic theory in favour of
the really wacky theory of relativity. I, like Shankland, don't
understand what he is on about but I have a strong suspicion that he is
basically using the same argument as in 'The Evolution of Physics' but
wrapping it up in technical jargon. He is thinking in terms of a source
moving relative to an aether.
MMX posed a problem. Lorenz proposed a solution which made it *appear*
that the speed of light is constant w.r.t the observer (no question of
abandoning the concept of the aether). Einstein took that one stage
further and said - suppose the speed of light *is actually* constant
w.r.t the observer. At the time everyone was comfortable with the idea
of the Aether. They were after all desperately looking for an
explanation as to why MM hadn't found it! He was not interested in
ballistic theory. It did not fit in with the dogma of the day. As far as
he was concerned MMX had not shown there was no aether. It had not shown
that light is not an EM disturbance propagated in that aether. He was
trying to improve on the aether based Lorenz theory and concluded that
the reason for the null result of MMX is that for some unaccountable
reason the aether always appears stationary w.r.t the observer. The
aether concept may have become unpopular since but I believe that is the
way it was.
--
John Kennaugh
John C. Polasek
<jo...@kennaugh.demon.co.uk> wrote:
>In message
><Pine.LNX.4.33.030103...@localhost.localdomain>,
>Stephen Speicher <s...@speicher.com> writes
>>On Fri, 3 Jan 2003, John Kennaugh wrote:
>>
snip
>
>I interested specifically in why he rejected the ballistic theory. I
>don't quite see the relevance of the Fitzeau experiment to SR which is
>only about the speed of light in vacuum. James Bradley 1728 got the
>first really accurate value for c by assuming star aberration was due to
>the vector sum of the speed of light from stars and that of the earth
>i.e. the ballistic theory gave the right answer.
James Bradley used the vector sum of the two velocities, because this
sum was of two vectors at right angles. In other words, he measured,
not velocity sums, but rather the aberration angle v/c which is about
20 arc seconds (40 for measurements 6 months apart).
That does not justify the MM assumption of using v+c and v-c as vector
sums. Those quantities do not exist. As I pointed out, v + ic and
v - ic are the same value. Now that we know that v and c are always at
right angles, we can see why the MM experiment had to fail.
The fact that v and c are always at right angles leads directly to the
Lorentz contraction, which is really an angular transformation.
snip
>
>MMX posed a problem. Lorenz proposed a solution which made it *appear*
>that the speed of light is constant w.r.t the observer (no question of
>abandoning the concept of the aether). Einstein took that one stage
>further and said - suppose the speed of light *is actually* constant
>w.r.t the observer. At the time everyone was comfortable with the idea
>of the Aether. They were after all desperately looking for an
>explanation as to why MM hadn't found it! He was not interested in
>ballistic theory. It did not fit in with the dogma of the day. As far as
>he was concerned MMX had not shown there was no aether. It had not shown
>that light is not an EM disturbance propagated in that aether. He was
>trying to improve on the aether based Lorenz theory and concluded that
>the reason for the null result of MMX is that for some unaccountable
>reason the aether always appears stationary w.r.t the observer. The
>aether concept may have become unpopular since but I believe that is the
>way it was.
>
>
>--
>John Kennaugh
Bilge
>That does not justify the MM assumption of using v+c and v-c as vector
>sums. Those quantities do not exist. As I pointed out, v + ic and
>v - ic are the same value.
That's not true. Those quantities have the same magnitude. The magnitude
is larger than c. The phase angles differ by \pi. We don't measure a
magnitude larger than c. What you are saying is equivalent to saying that
a capacitor and an inductor with the same impedance are equivalent because
impedance because the magnitudes are the same and only differ by a phase
of \pi.
> Now that we know that v and c are always at
>right angles, we can see why the MM experiment had to fail.
>
>The fact that v and c are always at right angles leads directly to the
>Lorentz contraction, which is really an angular transformation.
So long as you define angular to include hyperbolic rotations:
+ v/ic = -i(v/c) = tan(A)
/|
/A| v/c = i tan(A)
/ | ic = tanh(iA)
/ |
+----+
v
Stephen Speicher
post responses, but this has been sitting here for a couple of
days. Because of several of your disrespectful comments (for
instance, calling what Einstein wrote "twaddle," which is
particularly annoying since you yourself have demonstrated such a
lack of understanding of the historical context and the technical
issues surrounding relativity), I was going to simply just ignore
your post. I decided, however, to give you one more try, but let
me say I will have no more patience for this sort of attitude
from you. If you want to benefit from what I know, act more
respectfully towards the things I value.
With that said, I still have little time and will therefore deal
with just one issue which seems to be your biggest area of
confusion.
On Sat, 11 Jan 2003, John Kennaugh wrote:
> In message
> <Pine.LNX.4.33.030103...@localhost.localdomain>,
> Stephen Speicher <s...@speicher.com> writes
>
> >
> >As to the second postulate: Einstein always used the MMX as
> >support for the first postulate, not the second postulate.
> >Briefly, building on the Fitzeau experiment, and aberration,
>
> I interested specifically in why he rejected the ballistic
> theory. I don't quite see the relevance of the Fitzeau
> experiment to SR which is only about the speed of light in
> vacuum.
I have previously given you several reasons for Einstein's
rejection of the emission theory, but I will here give you a few
more, and then connect it up with the Fitzeau experiment. Some
of Einstein's thinking in this area was tied into the issue of
light quanta. In a 1922 letter Einstein says:
"I rejected this [emission] hypothesis at that time,
because it leads to tremendous theoretical difficulties
(e.g., the explanation of shadow formation by a screen
that moves relative to the light source." [1]
In an earlier letter to Paul Efrenfest, Einstein explains the
simplicity and practicality associated with the velocity of light
being independent of the motion of source, and explains that if
you give this hypothesis up, then shadow formation requires "that
one introduce the ugly assumption that the light emitted by a
resonator depends on the kind of excitation (excitation by
'moving' radiation or excitation of another kind)." [2]
Another reason for rejecting the emission hypothesis had to do
with the expectation of interference if light from a moving
source is modified while passing through a thin stationary film.
"Further, an ever so permeable film would modify the
velocity of 'moving' light by a finite amount, so that
the interference ... would give rise to an entirely
unbelievable phenomena." [3]
In this same letter Einstein also identified his concern that if
the emission hypothesis were true, then why should the velocity
of light emitted from a stationary body be independent of the
color?
"But the strongest argument seemed to me: If in general
there is no fixed light velocity, then why should it be
that all light which is emitted by 'stationary bodies'
has a velocity _completely independent of the color_?
This seemed absurd to me." [3]
Also, in the same letter to Ehrenfest which I referenced above,
Einstein clarifies the issue further.
"I knew well that the principle of the constancy of the
velocity of light is completely independent of the
relativity postulate, and I considered what is more
probable, the principle of the constancy of c as
demanded by Maxwell's equations, or the constancy of c
exclusively for an observer sitting at the light
source. I decided on the former because I was convinced
that all light is defined by frequency and intensity
alone, completely independently of whether it comes
from a moving or resting light source. Further, it did
not occur to me to consider that deflected radiation
might behave differently with regard to propagation
from radiation newly emitted at the point in question.
Complications of this kind looked to me much more
unwarranted than those that the new concept of time
brings in its train."
Unfortunately, I am out of time, so I will have to deal with the
Fizeau experiment separately when I have some more time (perhaps
later tonight or tomorrow).
[1] April 1922 letter to Viscardini, Einstein Archives:
EA 25-301.
[2] Before 20 June 1912 letter to Paul Ehrenfest, Doc.
409, "The Collected Papers of Albert Einstein," Vol. 5,
The Swiss Years: Correspondence, 1902-1914, Ana Beck,
Translator, _Princeton University Press_, 1995.
[3] February 1952 letter to C.O. Hines, Einstein
Archives: EA 12-251.
John Kennaugh
>John, I hardly have time to read the group right now, much less
>post responses, but this has been sitting here for a couple of
>days. Because of several of your disrespectful comments (for
>instance, calling what Einstein wrote "twaddle," which is
>particularly annoying since you yourself have demonstrated such a
>lack of understanding of the historical context and the technical
>issues surrounding relativity), I was going to simply just ignore
>your post. I decided, however, to give you one more try, but let
>me say I will have no more patience for this sort of attitude
>from you. If you want to benefit from what I know, act more
>respectfully towards the things I value.
Thank you for taking the time to reply. It is genuinely appreciated.
I will give your comments more careful consideration but I too am up to
my neck in work at present. My problem is a very simple one however so
maybe you could concentrate your limited time in dealing with that.
Prior to the MM experiment the belief was that the speed was constant
w.r.t the aether therefore it could not be effected by the speed of the
source (ruling out the ballistic theory) and would be effected by the
speed of the observer relative to the aether (ruling out relativity).
MMX meant two things
1/ The expected dependence on the speed of the observer had not
materialised.
2/ The rationale that the speed of light cannot be effected by the speed
of the source because it is constant w.r.t the aether no longer holds.
There are two specific solutions to Maxwell's equations which might
still prove helpful.
Solution 1 - where the observer is stationary w.r.t the aether.
Solution 2 - where the source is stationary w.r.t the aether.
In the bit I quoted
>He gave up this approach
> because he could think of no form of differential
> equation which could have solutions representing waves
> whose velocity depended on the motion of the source.
Is he not basically saying that Solution 2 does not exist? Maybe I have
misunderstood but unless you can suggest a different meaning to mine his
statement makes no sense.
Relativity is based on solution 1 but that 'leads to tremendous
theoretical difficulties'. How can there be a form of differential
equation which could have solutions representing waves whose velocity
depended on the motion of the observer in the case where there isn't an
observer.
Either one can say that light cannot be emitted unless there is an
observer because the differential equation has no solution, which is
nonsense, or that when light is emitted from a source all possible
solutions exist simultaneously. You then have the problem that if an
observer can only see the light conforming to the solution which applies
to him i.e. light travelling at c relative to him, he cannot see the
light conforming to the infinite number of other solutions. He can
therefore see only 1/(infinity-1) of the total emitted light. i.e. None!
If you take Solution 2 there is no problem in resolving the difficulty
because one can say legitimately say that light cannot be emitted unless
there is a source so the fact that no solutions exist when there isn't
one is not a problem.
From my perspective Einstein seems very selective in deciding what is
'absurd' and 'entirely unbelievable' and 'leads to tremendous
theoretical difficulties'. That is a very human reaction.
You seem to be putting yourself in the position of a Einsteinian
fundamentalist. To prove a point all you have to do is quote the gospel
according to AE.
I don't know what that means. Do You?
>
>Another reason for rejecting the emission hypothesis had to do
>with the expectation of interference if light from a moving
>source is modified while passing through a thin stationary film.
>
> "Further, an ever so permeable film would modify the
> velocity of 'moving' light by a finite amount, so that
> the interference ... would give rise to an entirely
> unbelievable phenomena." [3]
>
>In this same letter Einstein also identified his concern that if
>the emission hypothesis were true, then why should the velocity
>of light emitted from a stationary body be independent of the
>color?
Even with my limited knowledge I could have a pretty good shot at
explaining that.
>
> "But the strongest argument seemed to me: If in general
> there is no fixed light velocity, then why should it be
> that all light which is emitted by 'stationary bodies'
> has a velocity _completely independent of the color_?
> This seemed absurd to me." [3]
>
Same point as above.
>Also, in the same letter to Ehrenfest which I referenced above,
>Einstein clarifies the issue further.
>
> "I knew well that the principle of the constancy of the
> velocity of light is completely independent of the
> relativity postulate, and I considered what is more
> probable, the principle of the constancy of c as
> demanded by Maxwell's equations, or the constancy of c
> exclusively for an observer sitting at the light
> source. I decided on the former because I was convinced
> that all light is defined by frequency and intensity
> alone, completely independently of whether it comes
> from a moving or resting light source.
This seems to deny the existence of Doppler! He also raises that old
chestnut that in some way the 'c' in Maxwell's equations supports
relativity. It doesn't. I have shown quite simply above that Maxwell's
equations are more at home with the ballistic theory.
>Further, it did
> not occur to me to consider that deflected radiation
> might behave differently with regard to propagation
> from radiation newly emitted at the point in question.
> Complications of this kind looked to me much more
> unwarranted than those that the new concept of time
> brings in its train."
>
>Unfortunately, I am out of time, so I will have to deal with the
>Fizeau experiment separately when I have some more time (perhaps
>later tonight or tomorrow).
>
>[1] April 1922 letter to Viscardini, Einstein Archives:
> EA 25-301.
>
>[2] Before 20 June 1912 letter to Paul Ehrenfest, Doc.
> 409, "The Collected Papers of Albert Einstein," Vol. 5,
> The Swiss Years: Correspondence, 1902-1914, Ana Beck,
> Translator, _Princeton University Press_, 1995.
>
>[3] February 1952 letter to C.O. Hines, Einstein
> Archives: EA 12-251.
>
--
John Kennaugh
Robert Kolker
John Kennaugh wrote:
> This seems to deny the existence of Doppler! He also raises that old
> chestnut that in some way the 'c' in Maxwell's equations supports
> relativity. It doesn't. I have shown quite simply above that Maxwell's
> equations are more at home with the ballistic theory.
If that were the case the Maxwells equations would be Galilean
invariant. A simple mathematical excercise shows this not to be the
case. Maxwellian Electromagnetics is Lorentzian right from the shipping
crate.
Bob Kolker
Bilge
Re: Gravity experiment / Michaelson Morley to usenet:
> MMX meant two things
>
>1/ The expected dependence on the speed of the observer had not
>materialised.
>
>2/ The rationale that the speed of light cannot be effected by the speed
>of the source because it is constant w.r.t the aether no longer holds.
>
>There are two specific solutions to Maxwell's equations which might
>still prove helpful.
>
>Solution 1 - where the observer is stationary w.r.t the aether.
>
>Solution 2 - where the source is stationary w.r.t the aether.
[...]
>In the bit I quoted
>
>> "He gave up this approach because he could think of no form
>> of differential equation which could have solutions representing
>> waves whose velocity depended on the motion of the source."
>
>Is he not basically saying that Solution 2 does not exist? Maybe I have
>misunderstood but unless you can suggest a different meaning to mine his
>statement makes no sense.
>
>Relativity is based on solution 1 but that 'leads to tremendous
>theoretical difficulties'.
Relativity is based upon both of what you term Solution 1 and
Solution 2.
> How can there be a form of differential
>equation which could have solutions representing waves whose velocity
>depended on the motion of the observer in the case where there isn't an
>observer.
>
> Either one can say that light cannot be emitted unless there is an
>observer because the differential equation has no solution, which is
Electromagnetic radiation is the emission of energy which can "escape"
to infinity. It doesn't depend upon an observer to receive it. However,
you should note that the emission of radiation requires an interaction
between two charges. It's not possible for a single charge to emit
radiation or else a charged particle would radiate away all of its mass.
>nonsense, or that when light is emitted from a source all possible
>solutions exist simultaneously. You then have the problem that if an
>observer can only see the light conforming to the solution which applies
>to him i.e. light travelling at c relative to him, he cannot see the
>light conforming to the infinite number of other solutions. He can
>therefore see only 1/(infinity-1) of the total emitted light. i.e. None!
The observervation of the light requires no knowledge of its origin.
Furthermore, the radiation is emitted in a direction which is tangential
to the acceleration of charge which emits the radiation.
>If you take Solution 2 there is no problem in resolving the difficulty
>because one can say legitimately say that light cannot be emitted unless
>there is a source so the fact that no solutions exist when there isn't
>one is not a problem.
Since that requires every source to be stationary with respect to the
ether, there certainly would be no problem, since every source would
be stationary and there would be no radiation at all. The only problem
occurs when comparing that to the real universe in which we observe
electromagnetic radiation.
[...]
>This seems to deny the existence of Doppler! He also raises that old
>chestnut that in some way the 'c' in Maxwell's equations supports
>relativity. It doesn't. I have shown quite simply above that Maxwell's
>equations are more at home with the ballistic theory.
A ballistic theory doesn't requuire any ether and since electromagnetic
radiation is quantized via the photon in qed, which is a relativistic
theory, why is that an argument against relativity?
John Kennaugh
<ro...@radioactivex.lebesque-al.net> writes
>John Kennaugh said some stuff about
>Re: Gravity experiment / Michaelson Morley to usenet:
>
> > MMX meant two things
> >
> >1/ The expected dependence on the speed of the observer had not
> >materialised.
> >
> >2/ The rationale that the speed of light cannot be effected by the speed
> >of the source because it is constant w.r.t the aether no longer holds.
> >
> >There are two specific solutions to Maxwell's equations which might
> >still prove helpful.
> >
> >Solution 1 - where the observer is stationary w.r.t the aether.
> >
> >Solution 2 - where the source is stationary w.r.t the aether.
>
>[...]
> >In the bit I quoted
> >
> >> "He gave up this approach because he could think of no form
> >> of differential equation which could have solutions representing
> >> waves whose velocity depended on the motion of the source."
> >
> >Is he not basically saying that Solution 2 does not exist? Maybe I have
> >misunderstood but unless you can suggest a different meaning to mine his
> >statement makes no sense.
> >
> >Relativity is based on solution 1 but that 'leads to tremendous
> >theoretical difficulties'.
>
> Relativity is based upon both of what you term Solution 1 and
>Solution 2.
** You will have to explain what you mean by that.
>
> > How can there be a form of differential
> >equation which could have solutions representing waves whose velocity
> >depended on the motion of the observer in the case where there isn't an
> >observer.
> >
> > Either one can say that light cannot be emitted unless there is an
> >observer because the differential equation has no solution, which is
>
> Electromagnetic radiation is the emission of energy which can "escape"
>to infinity. It doesn't depend upon an observer to receive it. However,
>you should note that the emission of radiation requires an interaction
>between two charges. It's not possible for a single charge to emit
>radiation or else a charged particle would radiate away all of its mass.
>
I am not questioning what you say but can see no relevance to the
argument.
> >nonsense, or that when light is emitted from a source all possible
> >solutions exist simultaneously. You then have the problem that if an
> >observer can only see the light conforming to the solution which applies
> >to him i.e. light travelling at c relative to him, he cannot see the
> >light conforming to the infinite number of other solutions. He can
> >therefore see only 1/(infinity-1) of the total emitted light. i.e. None!
>
> The observervation of the light requires no knowledge of its origin.
>Furthermore, the radiation is emitted in a direction which is tangential
>to the acceleration of charge which emits the radiation.
>
I am not questioning what you say but can see no relevance to the
argument.
> >If you take Solution 2 there is no problem in resolving the difficulty
> >because one can say legitimately say that light cannot be emitted unless
> >there is a source so the fact that no solutions exist when there isn't
> >one is not a problem.
>
> Since that requires every source to be stationary with respect to the
>ether,
You have missed the point. Maxwell believed in an aether and believed
his equations related to that aether. MMX showed that belief to be
misplaced. There must be solutions 1 and 2 of Maxwell's equations.
Following MMX those solutions represent two possibilities *the
equivalent of* each source being stationary w.r.t to its own aether and
*the equivalent of* each observer being stationary w.r.t his own aether.
The term aether is very unfashionable but if one accepts that all the
aether now is, is 'whatever it is which makes light travel at c',
Relativity requires an infinite number of aethers so that an infinite
number of observers can each be stationary w.r.t their own. All that
relativity has done is to rename the aether 'the frame of reference'
'The speed of light is always constant w.r.t the observers frame of
reference'
has simply replaced
'the speed of light is always constant w.r.t. the aether'.
Solution 1 gives you - The speed of light is always c w.r.t the
observers frame of reference.
Solution 2 gives you - The speed of light is always c w.r.t the sources
frame of reference.
If relativity can have as many frames of reference as it likes moving
relative to each other then so can the ballistic theory.
>there certainly would be no problem, since every source would
>be stationary and there would be no radiation at all.
I do not follow that argument at all.
>The only problem
>occurs when comparing that to the real universe in which we observe
>electromagnetic radiation.
>
>[...]
>
> >This seems to deny the existence of Doppler! He also raises that old
> >chestnut that in some way the 'c' in Maxwell's equations supports
> >relativity. It doesn't. I have shown quite simply above that Maxwell's
> >equations are more at home with the ballistic theory.
>
> A ballistic theory doesn't requuire any ether
No but one has to assume that in bulk photons can be modelled by a wave
equation. If you want a short cut to a suitable differential equation
with solutions representing waves whose velocity is constant w.r.t. the
source, the easiest route to find one is to assume that mathematically
it would be *the same as* using Solution 2 of Maxwell's equation and
assuming every source is stationary w.r.t its own independent aether.
>and since electromagnetic
>radiation is quantized via the photon in qed, which is a relativistic
>theory, why is that an argument against relativity?
What I am saying is that Maxwell's equations favour neither relativity
nor the ballistic theory. Martin Hogbin put it rather well "Maxwell's
equations give rise to an answer, in terms of a speed, to an unknown
question." Take away the universal aether then there is nothing in the
equations themselves which indicate what c is referenced to.
As far as I am concerned Relativity is based only on solution 1. [See my
comment above marked **. I don't understand your statement.] The problem
with relating c to the speed of the observer are:
1/ There is no conceivable reason why it should be.
2/ The equations become meaningless in the case where there isn't an
observer.
Neither of which apply in the case of the ballistic theory which is why
I suggested that Maxwell's equations were actually 'more at home with'
the Ballistic theory. That doesn't stop text book writers (and Martin
Hogbin recently) from saying:
>
>One feature of Maxwell's equations is that they did not include any
>terms which relate to the velocity of the source of the waves,
without adding "...nor any terms which relate to the velocity of the
observer."
--
John Kennaugh
Marion Hobba
Bilge wrote:
> Electromagnetic radiation is the emission of energy which can "escape"
> to infinity. It doesn't depend upon an observer to receive it. However,
> you should note that the emission of radiation requires an interaction
> between two charges. It's not possible for a single charge to emit
> radiation or else a charged particle would radiate away all of its mass.
>
Could someone clarify that for me thanks. Are you assuming all the mass is
of eltromagnetic origin or am I missing something. I know Feynman had a
absorber type theory that dealt with this type of thing is that what your
referring to. I have a lot of books on electromagnetism a simple reference
to one would suffice.
Thanks
Bill
Bilge
could be stationary with the respect to any ether?
[...]
>>
>> Electromagnetic radiation is the emission of energy which can "escape"
>>to infinity. It doesn't depend upon an observer to receive it. However,
>>you should note that the emission of radiation requires an interaction
>>between two charges. It's not possible for a single charge to emit
>>radiation or else a charged particle would radiate away all of its mass.
>I am not questioning what you say but can see no relevance to the
>argument.
OK, then nevermind. I was anticipating a possible subsequent
question.
>> >nonsense, or that when light is emitted from a source all possible
>> >solutions exist simultaneously. You then have the problem that if an
>> >observer can only see the light conforming to the solution which applies
>> >to him i.e. light travelling at c relative to him, he cannot see the
>> >light conforming to the infinite number of other solutions. He can
>> >therefore see only 1/(infinity-1) of the total emitted light. i.e. None!
>
>>
>> The observervation of the light requires no knowledge of its origin.
>>Furthermore, the radiation is emitted in a direction which is tangential
>>to the acceleration of charge which emits the radiation.
>I am not questioning what you say but can see no relevance to the
>argument.
Then, I'm not sure what to say, since that answered your question
in the only way I could make sense out of the question.
[...]
>> Since that requires every source to be stationary with respect to the
>>ether,
>
>You have missed the point. Maxwell believed in an aether and believed
>his equations related to that aether.
What maxwell believed, really is irrelevant.
> MMX showed that belief to be
>misplaced. There must be solutions 1 and 2 of Maxwell's equations.
>Following MMX those solutions represent two possibilities *the
>equivalent of* each source being stationary w.r.t to its own aether and
>*the equivalent of* each observer being stationary w.r.t his own aether.
Doesn't that seem rather a rather far-fetched property for the ether
which was supposed to function as a medium in order to understand the
propagation of light in terms of waves propagating in media? Having to
invent a "material" with such bizzare properties would seem to be
more effort than it's worth and even less physically appealing, since
the idea of the ether was an attempt to reduce the propagation of
light to someething more familiar, not more esoteric.
>The term aether is very unfashionable but if one accepts that all the
>aether now is, is 'whatever it is which makes light travel at c',
>Relativity requires an infinite number of aethers so that an infinite
>number of observers can each be stationary w.r.t their own. All that
>relativity has done is to rename the aether 'the frame of reference'
That doesn't solve anything. It only adds numerous other questions.
For example, the weak interaction is a force just like electromagnetism
is a force. The photon is massless and therefore electromagnetism has
an infinite range. The W+/- and Z are massive, and the weak force only
has a range of about 0.001 fm. Why should electromagnetism be special?
Despite the fact that einstein chose the speed of light to represnt
the quantity `c', it's really not what special relativity is about.
Special relativity is about a spacetime geometry in which the number
`c' represents some finite speed. Einstein knew of no other forces
at the time, so he had no reason to question why E&M should be special.
It was a logical assumption, given what was known and what he was
trying to explain (maxwell's equations).
However, _any_ massless particle will propagate at `c' and whether or
not light propagates at that speed depends upon the photon being massless.
Experiments place an upper limit on the photon mass around 1 x 10^-17 ev
(or possibly even less). So, to the best we can determine, light does
propagate at `c', but no relativistic theory hinges on this. The value `c'
represents the speed required for energy to propagate to infinity. A
massless photon is required if electric charge is conserved. So, if charge
is conserved, then light propagates at `c'.
>'The speed of light is always constant w.r.t the observers frame of
>reference' has simply replaced 'the speed of light is always constant
>w.r.t. the aether'.
And the puropse of the ether is what? To insure that light propagates
at `c'? Don't you think that there be some deeper connection to other
physical phenomena? I mean, simply inventing a very bizzare medium to
explain maxwell's equations is placing the equations before the physics.
It would be different if maxwell's equations pointed to an ether which
was then discovered, but instead, the reasons advanced by proponents
of an ether for not discovering it, become more and more elaborate
and are completely fixated on a single phenomena - the propagation
of light.
[...]
>If relativity can have as many frames of reference as it likes moving
>relative to each other then so can the ballistic theory.
What does "ballistic" have to do with anything?
[...]
>> A ballistic theory doesn't requuire any ether
>
>No but one has to assume that in bulk photons can be modelled by a wave
>equation.
So what? As far as that goes, newton's corp8scular theory of light
is equally satifactory.
[...]
> What I am saying is that Maxwell's equations favour neither relativity
>nor the ballistic theory.
Maxwell's equations favor light propagating at a fixed velocity.
At the time, special relativity offered the most economical explanation.
An ether theory is plauged with lots of additional difficulties, like
the transversality of light, the lack of any dispersion in the ether,
etc. Since that time, the principles underlying special relativity
(like invariance and symmetry) have been exploited repeatedly to the
extent that we now have a model which contains all forces but gravity,
and which does not rely on the photon being massless amd propagating
at `c'. Invariance requires light to propagate at `c' if charge is
conserved. On the other hand, inventing an ether for the sole purpose
of explaining the propagation speed of light at a constant speed,
requires inventing an unobservable and very bizarre material which
cannot be used to make any predictions about anything else but
the propagation speed of light.
> Martin Hogbin put it rather well "Maxwell's
>equations give rise to an answer, in terms of a speed, to an unknown
>question." Take away the universal aether then there is nothing in the
>equations themselves which indicate what c is referenced to.
The quantity `c' is referenced to any inertial observer.
>As far as I am concerned Relativity is based only on solution 1. [See my
>comment above marked **. I don't understand your statement.] The problem
>with relating c to the speed of the observer are:
>
>1/ There is no conceivable reason why it should be.
>2/ The equations become meaningless in the case where there isn't an
>observer.
>
>Neither of which apply in the case of the ballistic theory which is why
>I suggested that Maxwell's equations were actually 'more at home with'
>the Ballistic theory. That doesn't stop text book writers (and Martin
>Hogbin recently) from saying:
Maxwell's equations don't care. In order to properly explain
electromagnetic radiation, one needs a field theory. Maxwell's
equations say nothing about interference beyond that obtained
using geometric optics, for example. Geometric optics can be
formulated equally well in terms of classical waves and _classical_
particles. Maxwell's equations only alter that by requiring the
particles to be massless. The real importance of special relativity
enters only after you use to obtain a quantum mechanical description
which is relativistic.
>>One feature of Maxwell's equations is that they did not include any
>>terms which relate to the velocity of the source of the waves,
>
>without adding "...nor any terms which relate to the velocity of the
>observer."
Because no sources are present in free space and it's rather difficult
to see how light apparently propagates at the same speed regardless of
the source chosen to use for a measurement. Even if the earth were
"stationary" in the ether, the fact that we observe the extraterrestrial
sources of light shift in the sky as the earth rotates, indicates
the sources have some relative velocity with respect to us. If the
speed of light appears to be constant in spite of the relative velocites
of a lot of different sources, then a logical assumption is that the
speed of light is independent of the motion of those sources.
Stephen Speicher
>
> You seem to be putting yourself in the position of a Einsteinian
> fundamentalist. To prove a point all you have to do is quote the gospel
> according to AE.
>
You wanted to know what Einstein's thinking was in regard to a
particular issue ("I [am] interested specifically in why he
rejected the ballistic theory."), so I provided a series of
relevant quotes, and interspersed my comments. For this I am
rewarded with being called a "fundamentalist" quoting the
"gospel." In the future you can do your own damn research, or
remain just as ignorant and confused as you are. Instead I'll
devote my effort where it is both understood, and appreciated.
Bilge
Re: Gravity experiment / Michaelson Morley to usenet:
>
>> Electromagnetic radiation is the emission of energy which can "escape"
>> to infinity. It doesn't depend upon an observer to receive it. However,
>> you should note that the emission of radiation requires an interaction
>> between two charges. It's not possible for a single charge to emit
>> radiation or else a charged particle would radiate away all of its mass.
>>
>
>Could someone clarify that for me thanks. Are you assuming all the mass is
>of eltromagnetic origin or am I missing something.
Assume that you have an electron which emits a photon. Then, from the
conservation of the four-momentum, we have (supressing the indicies
and using `.' or simply a ^2 to denote the scalar product of two
four-vectors where it's not confusing, ):
p = initial electron momentum
p^2 = (p' + q)^2 p' = final electron momentum
q = photon momentum
p^2 = p'^2 + 2p.q + q^2
Since all of these are frame invariant quantities, and in any frame,
p^2 = p'^2 = m^2, and for a massless photon, q^2 = 0, we get:
m^2 = m^2 + 2p.q + 0
or:
p.q = \gamma m\hbar w - \gamma\beta m\hbar w = 0
\beta = 0
So an electron cannot emit a massless photon and conserve energy and
momentum. That goes for two or more photons as well. While it's possible
to conserve momentum by emitting two photons, one can't conserve energy.
On the other hand, if the photon had a mass, then the electron could
radiate one, provided the electron became a lighter particle.
It did just occur to me that there are two more possibilities. The
electron could emit two photons if it did radiate _all_ of it's mass into
the two photons, except for two problems. (1) the process wouldn't
conserve angular momentum, and (2) it wouldn't conserve charge. The first
could be dispensed with if the decay were to two photons + neutrino, but
the second problem can't be avoided.
>I know Feynman had a
>absorber type theory that dealt with this type of thing is that what your
>referring to. I have a lot of books on electromagnetism a simple reference
>to one would suffice.
If you are referring to the need for an interaction, the reason is
the following. From above, we know that the electron must emit a
particle of some finite mass in order to "radiate" one (I'm using
the term radiate somewhat loosely here). But then the electron would
have to lose some mass in the process. If on the otherhand, you have
a second, charge, the interaction produces the radiated photon as:
~ The virtual photon connecting the two vertices
\ ~ / transfers some momentum between the two charges.
|~ / If the charge depicted on the right is much heavier
/ ~~~~~\ than the electron, like a proton, the interaction
cause the electron to accelerate (or be off mass-shell).
So, it will have to radiate a photon so that the
interaction will be lorentz invariant.
John Kennaugh
<Pine.LNX.4.33.03011...@localhost.localdomain>, Stephen
Speicher <s...@speicher.com> writes
>On Fri, 17 Jan 2003, John Kennaugh wrote:
>>
>> You seem to be putting yourself in the position of a Einsteinian
>> fundamentalist. To prove a point all you have to do is quote the gospel
>> according to AE.
>>
>
>You wanted to know what Einstein's thinking was in regard to a
>particular issue ("I [am] interested specifically in why he
>rejected the ballistic theory."), so I provided a series of
>relevant quotes, and interspersed my comments. For this I am
>rewarded with being called a "fundamentalist" quoting the
>"gospel." In the future you can do your own damn research, or
>remain just as ignorant and confused as you are. Instead I'll
>devote my effort where it is both understood, and appreciated.
>
I apologise if I have upset you. I do appreciate your help. Maybe I have
misunderstood your position. If you do not, and have never, claimed to
endorse the arguments provided by the quotes and are simply providing me
with quotes you feel are relevant to my search then I apologise that I
have misunderstood and I must indeed seem very ungrateful. I am not I
assure you.
The position as I saw it, (mistakenly?) was that you were claiming that
Einstein had indeed given the ballistic theory proper consideration and
the quotes you provided showed, *to your own satisfaction* that to be
the case. I therefore assumed that when I spotted what appears to me to
be a major flaw that you would be prepared to defend what Einstein said
and show me the error of my thinking. Instead you gave me some more
quotes. Obviously if I have misread your role it was unreasonable of me
to expect you to clarify what Einstein meant.
--
John Kennaugh