Gravity

[Metspitzer]

Lawrence Krauss said in a TV show that if the sun were to disappear,
it would take the earth 8 min to react. This would suggest that
gravity moves at the speed of light.

Does everyone agree?

[Michael Siemon]

In article <dg1587h13tsv5u20s...@4ax.com>,

yes.

[Mitchell Coffey]

Yes, but I do believe in teaching the controversy.

Mitchell Coffey

[alextangent]

A bit simplistic, and as such I disagree with Krauss. Assume that the
sun suddenly stops shining to illustrate. From the perspective of
someone standing on the sun, it would take the earth 16 minutes to go
dark from a local "now"; 8 minutes for the last photon to make it to
earth, and 8 minutes for the reflected photon to make it back. From
the perspective of someone standing on the earth, it would go dark
"now", with no delay and no warning.

Only for observers that are equidistant to both earth and sun is the
answer is 8 minutes. From their local "now", they will see the sun go
out first (the direct light taking a path length of 1), and the earth
8 minutes later (a path length of 2 for the reflected light).

There's no such thing as a universal "now" by which to clock this kind
of event.

But yes, gravity appears to propagate at the speed of light.

[jillery]

On Tue, 27 Sep 2011 22:30:59 -0400, Metspitzer <kilo...@charter.net>
wrote:

Almost certainly not, but FWIW I am one who does.

[pgmoni]

There is an interesting discussion about the speed of gravity
(infinite or light speed) at

http://www.intalek.com/Index/Projects/Research/TheSpeedofGravity-WhattheExperimentsSay.htm

Philippe

[Burkhard]

It is true for the free version of gravity that most people use. The
paid-for "executive" version is faster though, and has fewer bugs.

[Ernest Major]

In message <dg1587h13tsv5u20s...@4ax.com>, Metspitzer
<kilo...@charter.net> writes

The scientific consensus is that changes in gravitational fields
propagate at the speed of light.
--
alias Ernest Major

[Robert Carnegie: Fnord: cc talk-origins@moderators.isc.org]

On Sep 28, 3:30 am, Metspitzer <kilow...@charter.net> wrote:

It is not possible for the sun, or rather its mass, to disappear. In
certain circumstances we can imagine it accelerating away rapidly.
For instance, if the sun was large enough to explode as a supernova,
which it isn't, a large proportion of its mass would be rapidly
ejected outwards, after which, in Newton's terms, we would not feel
its gravity. It may be more complicated with Einstein. (If the Sun
is converted to an evenly distributed hollow sphere of expanding gas
containing a vacuum, and the Earth is anywhere in the vacuum space
inside the sphere, Newton's laws say that there is no force of gravity
on the Earth from the mass of gas around it, or, rather, the gravity
of the mass in different directions cancels out. I think the same
applies if it's a ring instead of a sphere, but it must be
symmetrical.)

So, so far, I disagree; the sun's mass cannot disappear from its
present location, all at once. At most, it could move, or explode.
And that demands energy, and that has mass too - sort of.

The sun in fact is very gradually losing mass, both as energy, and as
the "solar wind" of the stuff of the sun blowing away, basically. But
most of its mass will still be there when it expands to red giant
size, then ejects a "planetary nebula", and contracts to a white
dwarf, about five billion years from now.

I'm led to believe that in the meantime it will get gradually hotter,
and in about one billion years all of the water on Earth's surface
will be evaporated, presumably rendering it uninhabitable to life if
that isn't already the case for other reasons.

So much for the Sun, then. And the Earth.

Massive objects moving around in certain ways theoretically generates
gravity waves, but these have not been detected.

Gravity in General Relativity is considered to be not a force but the
shape of spacetime, and objects are not pulled by gravity but follow a
straight line, but a straight line through bent spacetime looks like a
curve.

Some particular implications of the theory of relativity have been
tested by observing odd objects in deep space such as pulsars (rapidly
rotating neutron stars) with companion stars, but I don't know if that
includes the finite speed of gravity.

I gather that a planet was very recently detected orbiting in a binary
star system. Extended study of its motion, which probably would be
extremely difficult, might give a clue as to whether its orbit around
two "moving" stars is consistent with a finite speed of propagation of
gravity.

[J. J. Lodder]

Van Flandern is a notorious crackpot,
don't take his word for it,

Jan

[J. J. Lodder]

That's not just a consensus,
it's a must, if you want to have general relativity.

Anyone who want something else
has to formulate another theory of gravity,

Jan

[Bill]

Well, for most gravity, yes, but for the gravity produced by the
neutrino, that goes just a wee bit faster.

[Mark Buchanan]

Put me firmly in the don't know camp (mainly because I don't know much
about it).

Do gravitons exist?

http://en.wikipedia.org/wiki/Graviton

Mark

[VoiceOfReason]

On Sep 27, 10:30 pm, Metspitzer <kilow...@charter.net> wrote:

But what's the speed of levity?

[J. J. Lodder]

If that means detectable, no,
not for the forseeeable future.
-Classical- gravitational waves may be detected
in the near future,

Jan

[Dakota]

On 9/28/2011 5:48 AM, Robert Carnegie: Fnord: cc

talk-o...@moderators.isc.org wrote:
> On Sep 28, 3:30 am, Metspitzer<kilow...@charter.net> wrote:
>> Lawrence Krauss said in a TV show that if the sun were to disappear,
>> it would take the earth 8 min to react. This would suggest that
>> gravity moves at the speed of light.
>>
>> Does everyone agree?
>
> It is not possible for the sun, or rather its mass, to disappear. In
> certain circumstances we can imagine it accelerating away rapidly.
> For instance, if the sun was large enough to explode as a supernova,
> which it isn't, a large proportion of its mass would be rapidly
> ejected outwards, after which, in Newton's terms, we would not feel
> its gravity. It may be more complicated with Einstein. (If the Sun
> is converted to an evenly distributed hollow sphere of expanding gas
> containing a vacuum, and the Earth is anywhere in the vacuum space
> inside the sphere, Newton's laws say that there is no force of gravity
> on the Earth from the mass of gas around it, or, rather, the gravity
> of the mass in different directions cancels out. I think the same
> applies if it's a ring instead of a sphere, but it must be
> symmetrical.)
>
> So, so far, I disagree; the sun's mass cannot disappear from its
> present location, all at once. At most, it could move, or explode.
> And that demands energy, and that has mass too - sort of.
>

You aren't taking the popular 'goddidit' possibility into consideration. :)

[Dakota]

On 9/27/2011 11:43 PM, alextangent wrote:
> On Sep 27, 7:30 pm, Metspitzer<kilow...@charter.net> wrote:
>> Lawrence Krauss said in a TV show that if the sun were to disappear,
>> it would take the earth 8 min to react. This would suggest that
>> gravity moves at the speed of light.
>>
>> Does everyone agree?
>
> A bit simplistic, and as such I disagree with Krauss. Assume that the
> sun suddenly stops shining to illustrate. From the perspective of
> someone standing on the sun, it would take the earth 16 minutes to go
> dark from a local "now"; 8 minutes for the last photon to make it to
> earth, and 8 minutes for the reflected photon to make it back. From
> the perspective of someone standing on the earth, it would go dark
> "now", with no delay and no warning.
>

It seems to me that a person on the lit side of Earth would continue to
see light from the Sun until the last photon arrived 8 minutes after the
Sun went dark.

[r norman]

About a half century ago, I heard Feynman give a talk on the quantum
theory of gravity -- on gravitons. I could understand essentially
nothing of the content except for his triumphant conclusion. (quoting
as closely as I can recall) "As you can see, the theory predicts that
all these properties of gravitons are far too small to be detected. We
have never detected these properties. So the experimental evidence
proves my theory is correct!"

[Harry K]

> > But yes, gravity appears to propagate at the speed of light.- Hide quoted text -
>
> - Show quoted text -

True but as Alex pointed out, to that observer it would be
instantaneous. He wouldn't know that the sun went out 8 minutes
prior.

Harry K

[r norman]

On the other hand, to an observer riding on the last photon to leave
the sun, it would never get dark. "What do you mean the sun
disappears? I was just there!"

[Harry K]

Depends on the density of the audiance.

Harry K

[Kalkidas]

It's the other way around: light moves at the speed of gravity.

[Glenn]

"Metspitzer" <kilo...@charter.net> wrote in message
news:dg1587h13tsv5u20s...@4ax.com...

That would depend on how the Earth reacted. May I pass?

[Glenn]

"r norman" <r_s_n...@comcast.net> wrote in message
news:idd6879p6i4oqj9k1...@4ax.com...

How often do you see observers riding photons, Richard?

[r norman]

They go by so quickly it is hard to tell.

[Burkhard]

My mother used to make a gravity with the Sunday roast that tasted
just great, but the pounds ended up on your hips faster than the
speed of light

[Glenn]

"r norman" <r_s_n...@comcast.net> wrote in message

news:cue687h1nd3skfa8m...@4ax.com...

> >> >True but as Alex pointed out, to that observer it would be
> >> >instantaneous. He wouldn't know that the sun went out 8 minutes
> >> >prior.
> >> >
> >>
> >> On the other hand, to an observer riding on the last photon to leave
> >> the sun, it would never get dark. "What do you mean the sun
> >> disappears? I was just there!"
> >>
> >How often do you see observers riding photons, Richard?
> >
>
> They go by so quickly it is hard to tell.
>

How do you know you aren't suffering from an illusion?

[alextangent]

On Sep 28, 8:46�am, "Glenn" <glennshel...@invalid.invalid> wrote:
> "r norman" <r_s_nor...@comcast.net> wrote in message

>
> news:cue687h1nd3skfa8m...@4ax.com...
>
>
>
>
>
>
>
> > On Wed, 28 Sep 2011 08:17:55 -0700, "Glenn"

> > <glennshel...@invalid.invalid> wrote:
>
> > >"r norman" <r_s_nor...@comcast.net> wrote in message

Optical illusion?

[r norman]

On Wed, 28 Sep 2011 08:46:26 -0700, "Glenn"

It was a photon. You could actually see it with your own eyes.

[Dakota]

It depends on when you start the clock. I was thinking in terms of
Metspitzer' post about Krauss's statement the it would take the Earth 8
minutes to react.

Whether an observer knew it or not, it would take 8 minutes for him to
react.

I certainly don't want to pursue the matter. I understand and accept
both points of view. Thanks for posting.

[Glenn]

"alextangent" <bl...@rivadpm.com> wrote in message
news:46caf6a6-8455-4ec7...@8g2000yqm.googlegroups.com...

How would you know?

[James Beck]

This spans the crack between a priori and a posteriori.

[Glenn]

"James Beck" <jdbec...@gmail.com> wrote in message
news:c7b2bbfb-70b7-4dfd...@i33g2000yqm.googlegroups.com...

Take a bow!

[Glenn]

"r norman" <r_s_n...@comcast.net> wrote in message

news:mfh687l2nh6uhfphg...@4ax.com...

How do you know I wasn't suffering from an illusion? Besides, I wasn't even
there.

[wiki trix]

> Harry K- Hide quoted text -

>
> - Show quoted text -

Simultaneity is not absolute.

[Bob Casanova]

On Wed, 28 Sep 2011 02:41:44 -0700 (PDT), the following
appeared in talk.origins, posted by Burkhard
<b.sc...@ed.ac.uk>:

>On Sep 28, 3:30 am, Metspitzer <kilow...@charter.net> wrote:
>> Lawrence Krauss said in a TV show that if the sun were to disappear,
>> it would take the earth 8 min to react.  This would suggest that
>> gravity moves at the speed of light.
>>
>> Does everyone agree?
>

>It is true for the free version of gravity that most people use. The
>paid-for "executive" version is faster though, and has fewer bugs.

Is the ability to turn it off at will and soar with the
eagles included in the full-up version? If so I'll need to
re-think my budget.
--

Bob C.

"Evidence confirming an observation is
evidence that the observation is wrong."
- McNameless

[Mark Buchanan]

On Sep 27, 10:30 pm, Metspitzer <kilow...@charter.net> wrote:
> Lawrence Krauss said in a TV show that if the sun were to disappear,
> it would take the earth 8 min to react.  This would suggest that
> gravity moves at the speed of light.
>
> Does everyone agree?

In Tony's universe Earth would not react at all. There would be a
slight chance that Mercury or Venus would nail us though.

Mark

[Bob Casanova]

On Wed, 28 Sep 2011 10:45:16 -0400, the following appeared
in talk.origins, posted by r norman
<r_s_n...@comcast.net>:

Feynman was notorious for his wit, and this is a perfect
example. Thanks!

I will now go sit and contemplate the number of undetectable
FSM clones which can occupy the point of a pin...

[Bob Casanova]

On Wed, 28 Sep 2011 07:48:52 -0700 (PDT), the following
appeared in talk.origins, posted by Harry K
<turnk...@hotmail.com>:

>On Sep 28, 7:42 am, Dakota <ma...@NOSPAMmail.com> wrote:
>> On 9/27/2011 11:43 PM, alextangent wrote:> On Sep 27, 7:30 pm, Metspitzer<kilow...@charter.net>  wrote:
>> >> Lawrence Krauss said in a TV show that if the sun were to disappear,
>> >> it would take the earth 8 min to react.  This would suggest that
>> >> gravity moves at the speed of light.
>>
>> >> Does everyone agree?

>> > A bit simplistic, and as such I disagree with Krauss. Assume that the
>> > sun suddenly stops shining to illustrate. From the perspective of
>> > someone standing on the sun, it would take the earth 16 minutes to go
>> > dark from a local "now"; 8 minutes for the last photon to make it to
>> > earth, and 8 minutes for the reflected photon to make it back. From
>> > the perspective of someone standing on the earth, it would go dark
>> > "now", with no delay and no warning.

>> It seems to me that a person on the lit side of Earth would continue to
>> see light from the Sun until the last photon arrived 8 minutes after the
>> Sun went dark.

>> > Only for observers that are equidistant to both earth and sun is the
>> > answer is 8 minutes. From their local "now", they will see the sun go
>> > out first (the direct light taking a path length of 1), and the earth
>> > 8 minutes later (a path length of 2 for the reflected light).
>>
>> > There's no such thing as a universal "now" by which to clock this kind
>> > of event.

>> > But yes, gravity appears to propagate at the speed of light.

>True but as Alex pointed out, to that observer it would be
>instantaneous. He wouldn't know that the sun went out 8 minutes
>prior.

Sure he would, if he knew both the distance to the sun and
the value of c. He just wouldn't know it in advance; the
observation and the knowledge would occur simultaneously (or
as close to simultaneously as nerve propagation and memory
retrieval allow). ;-)

[Bob Casanova]

On Wed, 28 Sep 2011 08:15:28 -0700, the following appeared
in talk.origins, posted by Kalkidas <e...@joes.pub>:

Gravity, at least the sort under consideration here, doesn't
"move" at all; it's a property of mass, not a force
propagated by particles, virtual or otherwise.

[r norman]

On Wed, 28 Sep 2011 10:57:37 -0700, Bob Casanova <nos...@buzz.off>
wrote:

>On Wed, 28 Sep 2011 08:15:28 -0700, the following appeared
>in talk.origins, posted by Kalkidas <e...@joes.pub>:
>
>>On 9/27/2011 7:30 PM, Metspitzer wrote:
>>> Lawrence Krauss said in a TV show that if the sun were to disappear,
>>> it would take the earth 8 min to react. This would suggest that
>>> gravity moves at the speed of light.
>>>
>>> Does everyone agree?
>>>
>>
>>It's the other way around: light moves at the speed of gravity.
>
>Gravity, at least the sort under consideration here, doesn't
>"move" at all; it's a property of mass, not a force
>propagated by particles, virtual or otherwise.

Charge, at least the sort under consideration here, doesn't "move" at
all. It is a property of some fundamental particles, not a force

propagated by particles, virtual or otherwise.

No, somehow that doesn't work. Neither does the gravity one.

[alextangent]

On Sep 28, 10:55 am, Bob Casanova <nos...@buzz.off> wrote:
> On Wed, 28 Sep 2011 07:48:52 -0700 (PDT), the following
> appeared in talk.origins, posted by Harry K

> <turnkey4...@hotmail.com>:

Distance is defined in terms of c.

> He just wouldn't know it in advance; the
> observation and the knowledge would occur simultaneously (or
> as close to simultaneously as nerve propagation and memory
> retrieval allow). ;-)

That's true.

[Glenn]

"r norman" <r_s_n...@comcast.net> wrote in message

news:c2p687l34du515gl8...@4ax.com...

What is under "consideration" is the sudden absence of the gravitational
effect of the Sun on the Earth. In that respect, speed is relevant.

"the speed at which changes in a gravitational field propagate."
http://en.wikipedia.org/wiki/Speed_of_gravity

[RichD]

On Sep 27, Metspitzer <kilow...@charter.net> wrote:
> Lawrence Krauss said in a TV show that if the sun were to
> disappear, it would take the earth 8 min to react.  This would
> suggest that gravity moves at the speed of light.
>
> Does everyone agree?

No, I disagree. Gravity propagates at a different speed.

That's my opinion, which I'm entitled to, and
deserves respect, as does every opinion.

Thank you for asking.

--
Rich

[Mike Painter]

On 9/27/2011 7:53 PM, Mitchell Coffey wrote:

> On 9/27/2011 10:30 PM, Metspitzer wrote:
>> Lawrence Krauss said in a TV show that if the sun were to disappear,
>> it would take the earth 8 min to react. This would suggest that
>> gravity moves at the speed of light.
>>
>> Does everyone agree?
>

> Yes, but I do believe in teaching the controversy.
>
> Mitchell Coffey
>
>
It does not matter when it happens
The important thing is that the earth and everybody on it would finally
go straight.
(This would work better if the two biblical lights in the sky the sun
and the moon disappeared.)

[Rolf]

We always have to consider relativity; we are not living in a
three-dimensional universe, with the speed of light just tacked on to it. It
is integrated, making it a four-dimensional "thing". That's at least what I
think, but I know very little about such things...

[alextangent]

On Sep 28, 9:13 am, "Glenn" <glennshel...@invalid.invalid> wrote:
> "alextangent" <b...@rivadpm.com> wrote in message

You'd hear it, like the joke, go whooshing over your head.

[alextangent]

I've got a theory that really thin people move much faster than fat
folks. Perhaps it's the speed of their local gravity.

[Glenn]

"alextangent" <bl...@rivadpm.com> wrote in message

news:b3f83039-f98f-4171...@m37g2000yqc.googlegroups.com...

You seem to know a lot.

[Paul J Gans]

Burkhard <b.sc...@ed.ac.uk> wrote:

>On Sep 28, 3:30 am, Metspitzer <kilow...@charter.net> wrote:
>> Lawrence Krauss said in a TV show that if the sun were to disappear,
>> it would take the earth 8 min to react.  This would suggest that
>> gravity moves at the speed of light.
>>
>> Does everyone agree?

>It is true for the free version of gravity that most people use. The
>paid-for "executive" version is faster though, and has fewer bugs.

Now THAT is funny!

--
--- Paul J. Gans

[Paul J Gans]

So THAT is where the hips are! Who knew?

[alextangent]

I make light of it.

[Harry K]

On Sep 28, 8:16 am, "Glenn" <glennshel...@invalid.invalid> wrote:
> "Metspitzer" <kilow...@charter.net> wrote in message
>
> news:dg1587h13tsv5u20s...@4ax.com...> Lawrence Krauss said in a TV show that if the sun were to disappear,

> > it would take the earth 8 min to react.  This would suggest that
> > gravity moves at the speed of light.
>
> > Does everyone agree?
>

> That would depend on how the Earth reacted. May I pass?

Depends on what you want to pass.

Harry K

[John S. Wilkins]

Glenn <glenns...@invalid.invalid> wrote:

> "r norman" <r_s_n...@comcast.net> wrote in message

> news:cue687h1nd3skfa8m...@4ax.com...
> > On Wed, 28 Sep 2011 08:17:55 -0700, "Glenn"

> > <glenns...@invalid.invalid> wrote:
> >
> > >"r norman" <r_s_n...@comcast.net> wrote in message
> > >news:idd6879p6i4oqj9k1...@4ax.com...
...

> > >> On the other hand, to an observer riding on the last photon to leave
> > >> the sun, it would never get dark. "What do you mean the sun
> > >> disappears? I was just there!"
> > >>
> > >How often do you see observers riding photons, Richard?
> > >
> > They go by so quickly it is hard to tell.
> >
> How do you know you aren't suffering from an illusion?

They wave as they go past.
--
John S. Wilkins, Associate, Philosophy, University of Sydney
http://evolvingthoughts.net
But al be that he was a philosophre,
Yet hadde he but litel gold in cofre

[John S. Wilkins]

Harry K <turnk...@hotmail.com> wrote:

And that depends on what you ate.

[jillery]

Yeppers!

[timoth...@gmail.com]

Quote from paper:

"How then does the direction of Earth's acceleration compare with the direction of the visible Sun? By direct calculation from geometric ephemerides fitted to such observations, such as those published by the U.S. Naval Observatory or the Development Ephemerides of the Jet Propulsion Laboratory, the Earth accelerates toward a point 20 arc seconds in front of the visible Sun, where the Sun will appear to be in 8.3 minutes. In other words, the acceleration now is toward the true, instantaneous direction of the Sun now, and is not parallel to the direction of the arriving solar photons now. This is additional evidence that forces from electromagnetic radiation pressure and from gravity do not have the same propagation speed."

Apropos of the geocentric looniness elsewhere in t.o., this observed phenomenon would not occur if the Earth was stationary and the Sun was doing the accelerating, yes?

[Walter Bushell]

In article <1k8d0y6.1dccxl08t9i3gN%jo...@wilkins.id.au>,

jo...@wilkins.id.au (John S. Wilkins) wrote:

> Harry K <turnk...@hotmail.com> wrote:
>
> > On Sep 28, 8:16 am, "Glenn" <glennshel...@invalid.invalid> wrote:
> > > "Metspitzer" <kilow...@charter.net> wrote in message
> > >
> > > news:dg1587h13tsv5u20s...@4ax.com...
> > > > Lawrence Krauss said in a TV show that if the sun were to disappear,
> > > > it would take the earth 8 min to react. This would suggest that
> > > > gravity moves at the speed of light.
> > >
> > > > Does everyone agree?
> > >
> > > That would depend on how the Earth reacted. May I pass?
> >
> > Depends on what you want to pass.
> >
> And that depends on what you ate.

And, of course, the state of your digestive system.

--
Ignorance is no protection against reality. -- Paul J Gans

[Glenn]

"Walter Bushell" <pr...@panix.com> wrote in message
news:proto-6D16FD....@news.panix.com...

You have to know these things when you're a king, you know.

[Robert Carnegie: Fnord: cc talk-origins@moderators.isc.org]

Is this an "observed phenomenon", or is it an error in constructing
the predictions in ephemerides, for this very reason?

Incidentally, I've been told (as a viewer of the _QI_ television
programme) that when you see the sun set on the horizon, even /
without/ that eight light-minutes factor, it"s "really" below the
horizon. That is, the light is bent in the atmosphere, so that you
see the Sun higher than it actually is.

Or was it the other way around...

That should also apply when you see a satellite such as the
International Space Station close to the horizon...?

[alextangent]

On Sep 28, 9:15 pm, j...@wilkins.id.au (John S. Wilkins) wrote:
> Glenn <glennshel...@invalid.invalid> wrote:

> > "r norman" <r_s_nor...@comcast.net> wrote in message

> >news:cue687h1nd3skfa8m...@4ax.com...
> > > On Wed, 28 Sep 2011 08:17:55 -0700, "Glenn"

> > > <glennshel...@invalid.invalid> wrote:
>
> > > >"r norman" <r_s_nor...@comcast.net> wrote in message

> > > >news:idd6879p6i4oqj9k1...@4ax.com...
> ...
> > > >> On the other hand, to an observer riding on the last photon to leave
> > > >> the sun, it would never get dark.  "What do you mean the sun
> > > >> disappears?  I was just there!"
>
> > > >How often do you see observers riding photons, Richard?
>
> > > They go by so quickly it is hard to tell.
>
> > How do you know you aren't suffering from an illusion?
>
> They wave as they go past.
> --

> John S. Wilkins, Associate, Philosophy, University of Sydneyhttp://evolvingthoughts.net

> But al be that he was a philosophre,
> Yet hadde he but litel gold in cofre

They're quite particular about waving.

[James Beck]

On Sep 28, 8:23 pm, Paul J Gans <gan...@panix.com> wrote:

Hmm. I'm suspect that we should program that question to an interface
rather than a concrete class. Both lead and gravitas cause the GPS
(gluteal positioning system) to return variable results.

[alextangent]

On Sep 28, 10:33 pm, timothya1...@gmail.com wrote:
> Quote from paper:
>
> "How then does the direction of Earth's acceleration compare with the direction of the visible Sun? By direct calculation from geometric ephemerides fitted to such observations, such as those published by the U.S. Naval Observatory or the Development Ephemerides of the Jet Propulsion Laboratory, the Earth accelerates toward a point 20 arc seconds in front of the visible Sun, where the Sun will appear to be in 8.3 minutes. In other words, the acceleration now is toward the true, instantaneous direction of the Sun now, and is not parallel to the direction of the arriving solar photons now. This is additional evidence that forces from electromagnetic radiation pressure and from gravity do not have the same propagation speed."

I've read and re-read that paragraph, and for the life of me I can't
make sense of it. The Moon and other planets will have considerable
influence too, and I would expect a constant 20arc seconds to be --
well, not constant.

I think it's complete whizzo grade A tosh.

[Paul J Gans]

Mine is almost always in the same state I'm in.

[Bob Casanova]

On Wed, 28 Sep 2011 14:16:55 -0400, the following appeared
in talk.origins, posted by r norman
<r_s_n...@comcast.net>:

Charge doesn't necessarily move, but when it does it's
carried by charged particles.

>No, somehow that doesn't work. Neither does the gravity one.

So gravitons are real and accepted as the carriers of
gravity? I thought that was restricted to ideas about
quantum gravity, with the GR version the result of the
deformation of space by mass (the "rubber sheet" analogy),
and no carriers required.

[Bob Casanova]

On Wed, 28 Sep 2011 11:24:21 -0700 (PDT), the following
appeared in talk.origins, posted by alextangent
<bl...@rivadpm.com>:

It certainly can be. It can also be defined using the
distance from the nose to the tip of the thumb of a selected
dead monarch. Either works for describing the relationship
of two bodies at rest with respect to each other, although
using c is likely to be more practical in many instances,
especially those involving astronomical distances (but not
the height of my ceiling).

[r norman]

There are border cases.

[r norman]

On Thu, 29 Sep 2011 09:55:17 -0700, Bob Casanova <nos...@buzz.off>

Gravitons exist assuming some reconciliation between quantum mechanics
and general relativity.

[Kleuskes & Moos]

On Tue, 27 Sep 2011 19:40:59 +0000, Michael Siemon wrote:

> In article <dg1587h13tsv5u20s...@4ax.com>,

> Metspitzer <kilo...@charter.net> wrote:
>
>> Lawrence Krauss said in a TV show that if the sun were to disappear, it
>> would take the earth 8 min to react. This would suggest that gravity
>> moves at the speed of light.
>>
>> Does everyone agree?
>

> yes.

Just being curious, but is there actually a practical way to measure that or
does it follow from accepted theory and Einsteins sayso? The speed of light
can be measured to a high degree of precision, but it's not easy to make objects
vanish which are big enough to exert a measurable gravity field.

And, AFAIK, a gravity wave has never been detected. Am I wrong?

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[J. J. Lodder]

Kleuskes & Moos <kle...@somewhere.else.net> wrote:

> On Tue, 27 Sep 2011 19:40:59 +0000, Michael Siemon wrote:
>
> > In article <dg1587h13tsv5u20s...@4ax.com>,
> > Metspitzer <kilo...@charter.net> wrote:
> >
> >> Lawrence Krauss said in a TV show that if the sun were to disappear, it
> >> would take the earth 8 min to react. This would suggest that gravity
> >> moves at the speed of light.
> >>
> >> Does everyone agree?
> >
> > yes.
>
> Just being curious, but is there actually a practical way to measure that

Yes, but no result, so far.

> or does it follow from accepted theory and Einsteins sayso?

That too.

> The speed of light
> can be measured to a high degree of precision,

Not really. It can't be measured at all.

> but it's not easy to make objects
> vanish which are big enough to exert a measurable gravity field.

You can't make anything vanish.

> And, AFAIK, a gravity wave has never been detected. Am I wrong?

No, except indirectly, by otherwise unexplainable energy loss,

Jan

[J. J. Lodder]

The problem with dead kings
is that they don't reproduce well,

Jan

[Burkhard]

On Sep 29, 7:20 pm, nos...@de-ster.demon.nl (J. J. Lodder) wrote:
> Bob Casanova <nos...@buzz.off> wrote:
> > On Wed, 28 Sep 2011 11:24:21 -0700 (PDT), the following
> > appeared in talk.origins, posted by alextangent

> > <b...@rivadpm.com>:

While that used to be the case, it ain't any longer

[Glenn]

"r norman" <r_s_n...@comcast.net> wrote in message

news:b69987155t05k2oi4...@4ax.com...

And disputes.

[carlip...@physics.ucdavis.edu]

Metspitzer <kilo...@charter.net> wrote:
> Lawrence Krauss said in a TV show that if the sun were to disappear,
> it would take the earth 8 min to react. This would suggest that
> gravity moves at the speed of light.

> Does everyone agree?

There's a discussion of this on the sci.physics FAQs,
http://math.ucr.edu/home/baez/physics/Relativity/GR/grav_speed.html
The short answer is that

1. there has been no direct measurement of the speed of gravity;
2. according to our best existing theory of gravity, general relativity,
gravity propagates at the speed of light;
3. observations of the Solar System are inconsistent with Newtonian
gravity with a speed-of-light propagation speed stuck in (this was
van Flandern's point, but he didn't understand enough general
relativity to realize that it didn't apply there);
4. observations of the Solar System are completely consistent with
general relativity, with speed-of-light propagation of gravity.

Masochists can look at my technical paper on point 4, at
http://arxiv.org/abs/gr-qc/9909087.

Steve Carlip

[Robert Carnegie: Fnord: cc talk-origins@moderators.isc.org]

On Sep 29, 7:20 pm, nos...@de-ster.demon.nl (J. J. Lodder) wrote:

> Bob Casanova <nos...@buzz.off> wrote:
> > On Wed, 28 Sep 2011 11:24:21 -0700 (PDT), the following
> > appeared in talk.origins, posted by alextangent

> > <b...@rivadpm.com>:

>
> > >Distance is defined in terms of c.
>
> > It certainly can be. It can also be defined using the
> > distance from the nose to the tip of the thumb of a selected
> > dead monarch. Either works for describing the relationship
> > of two bodies at rest with respect to each other, although
> > using c is likely to be more practical in many instances,
> > especially those involving astronomical distances (but not
> > the height of my ceiling).
>
> The problem with dead kings
> is that they don't reproduce well,

<http://www.goodreads.com/quotes/show/66881>
explains that monarchy travels faster than light.
"You can't have more than one king, and tradition demands that there
is no gap between kings, so when a king dies the succession must
therefore pass to the heir *instantaneously*."

[Walter Bushell]

In article <glennsheldon-j62s37$ii4$1...@dont-email.me>,

And borders in you intestines.

[Paul J Gans]

Henry I of England had 22 *known* bastards. That's royal
reproduction at its best.

[Mitchell Coffey]

Did Henry II have any sons who weren't bastards?

Mitchell

[Walter Bushell]

In article <j632r3$q68$1...@dont-email.me>,

Mitchell Coffey <mitchell...@gmail.com> wrote:

> Did Henry II have any sons who weren't bastards?
>
> Mitchell

Few are the monarchs that have sons that aren't bastards.

[John S. Wilkins]

Robert Carnegie: Fnord: cc talk-o...@moderators.isc.org
<rja.ca...@excite.com> wrote:

Kingeons are therefore superluminal. I wonder if the latest neutrino
result passed through any monarchs on the way?

[Mitchell Coffey]

Oh common, Wilkins! Everyone knows neutrinos can't pass through anything
super-dense!

Mitchell Coffey

[Mitchell Coffey]

On 9/29/2011 9:30 PM, Walter Bushell wrote:
> In article<j632r3$q68$1...@dont-email.me>,
> Mitchell Coffey<mitchell...@gmail.com> wrote:
>
>> Did Henry II have any sons who weren't bastards?
>>
>> Mitchell
>
> Few are the monarchs that have sons that aren't bastards.

Yeah, but check out The Lion in Winter and any Robin Hood movie.

Mitchell Coffey

[J. J. Lodder]

Robert Carnegie: Fnord: cc talk-o...@moderators.isc.org
<rja.ca...@excite.com> wrote:

Sure, but he doesn't know it yet,
unless it was his dagger,

Jan

[Paul J Gans]

I don't think so, except possibly for his son Henry, who died
relatively young.

[Paul J Gans]

Walter Bushell <pr...@panix.com> wrote:
>In article <j632r3$q68$1...@dont-email.me>,
> Mitchell Coffey <mitchell...@gmail.com> wrote:

>> Did Henry II have any sons who weren't bastards?
>>
>> Mitchell

>Few are the monarchs that have sons that aren't bastards.

Back then, if you were not a bastard, you didn't last long.

[Paul J Gans]

Odds are against it, but still...

[Paul J Gans]

That's Congress, not kings.

[Bob Casanova]

On Thu, 29 Sep 2011 20:20:43 +0200, the following appeared
in talk.origins, posted by nos...@de-ster.demon.nl (J. J.
Lodder):

Two points for the play on words. And...

True. Irrelevant to the question at hand, but true.

[Bob Casanova]

On Thu, 29 Sep 2011 13:04:16 -0400, the following appeared

OK. But pending that reconciliation (string theory seems
currently the best bet) I'd argue that there's no evidence
in "Relativity World" that gravitons exist, and no need for
them there, which was the starting point for my post.

[Bob Casanova]

On Fri, 30 Sep 2011 00:12:55 +0000 (UTC), the following
appeared in talk.origins, posted by Paul J Gans
<gan...@panix.com>:

And every single one was measurable *without* knowing the
value of c.

[Mitchell Coffey]

Last year's unfortunate Ridley Scott/Russell Crowe/Cate Blanchett Robin
Hood movie <spoiler>
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

begins shortly before the death of Cœur de Lion, which it depicts with
vague accuracy. King John is, as usual, the Center of All Evil in the
film, but, with big brother deceased, without the
awaiting-Richard's-Return-From-Captivity-or-the-Crusades MacGuffin that
usually works so well. (This is presumably better to allow for sequels.)

There is an Agent of All Evil, but curiously it is not The Sheriff of
Nottingham, who, curiously, is played as a comic butt. (Probably so as
not to remind audiences of Severus Snape's show-stealing turn in the
role for Kevin Costner's otherwise maximally unfortunate Robin Hood
flick 20 years ago.) Instead, the bad, bad guy - badder than King John,
who at least is anachronistically patriotic - is a guy nominally doing
stuff for John: one "Sir Godfrey." Sir Godfrey is really plotting to
betray John and the kingdom by selling out England's French possession
to Phillip II, then using Phillips assistance to make himself King of
England. This is to say, Sir Godfrey is playing roughly the game Henry
II's son Godfrey was historically conniving at upon his death while
Henry II was still alive.

We presumably see in the Godfrey transposition artifacts of the
evolution of the script, but my point here is that Mr. & Ms. Henry II's
Plantagenet boys were possessing of so much unpleasantness that to put a
new and nasty take on the franchise, Ridley and staff mined the real
Godfrey's activities from the period prior to the generally accepted
Robin Hood timeline.

By the way, the film ends with Mr. Hood having saved the kingdom -
having been allowed by John and all the loyal nobles to lead the main
English army against the invading French, despite Hood's previous
military experience having been limited to having been a longbowman in
Richard's crusading army. John nonetheless outlaws Hood for his Chartist
activities (this is really in the film, really). At the very end, Hood
and Blanchett (as Lady Marian - not Maid, she's a widow, and you're
already supposed to feel sorry enough for her) have encamped the merry
guys and local population in Sherwood Forest, as an anarcho-syndicalist
commune. (No, it doesn't explicitly say anarcho-syndicalist, but it's
there in the film.)

Great cast. Max von Sydow is in as Marian's Father-in-Law. William Hurt
plays William Marshal - who would have been astounded to know he been
portrayed in two major theatrical releases, having been done by Nigel
Stock in Lion in Winter - back in the '60s, when Peter O'Toole /owned/
the role of Henry II!

</spoiler>

Mitchell

[Bob Casanova]

On Thu, 29 Sep 2011 21:30:49 -0400, the following appeared
in talk.origins, posted by Walter Bushell <pr...@panix.com>:

>In article <j632r3$q68$1...@dont-email.me>,
> Mitchell Coffey <mitchell...@gmail.com> wrote:
>
>> Did Henry II have any sons who weren't bastards?

>Few are the monarchs that have sons that aren't bastards.

Measurably so...

[Bob Casanova]

On Fri, 30 Sep 2011 16:23:55 +0000 (UTC), the following
appeared in talk.origins, posted by Paul J Gans
<gan...@panix.com>:

>Walter Bushell <pr...@panix.com> wrote:

>>In article <j632r3$q68$1...@dont-email.me>,
>> Mitchell Coffey <mitchell...@gmail.com> wrote:
>
>>> Did Henry II have any sons who weren't bastards?

>>Few are the monarchs that have sons that aren't bastards.

>Back then, if you were not a bastard, you didn't last long.

"Back then"? You must live a sheltered life, my son... ;-)

[r norman]

On Fri, 30 Sep 2011 11:02:17 -0700, Bob Casanova <nos...@buzz.off>

There are two issues. Carlip, the final arbiter on all things physic,
declared that gravity does, indeed, propagate at the speed of light
according to general relativity. Gravity waves are part of general
relativity.

A separate issue is whether gravity, like all other phenomena which
appear in our own world to involve forces between particles, involves
an exchange of particles in the quantum mechanical - standard model
sense. Do you really believe that there can be no reconciliation ever
between between the two physics?

[RichD]

On Sep 29, carlip-nos...@physics.ucdavis.edu wrote:
> > Lawrence Krauss said in a TV show that if the sun were to disappear,
> > it would take the earth 8 min to react.  This would suggest that
> > gravity moves at the speed of light.
>

> There's a discussion of this on the sci.physics FAQs

> http://math.ucr.edu/home/baez/physics/Relativity/GR/grav_speed.html
> The short answer is that
>
> 1. there has been no direct measurement of the speed of gravity;
> 2. according to our best existing theory of gravity, general relativity,
>     gravity propagates at the speed of light;
> 3. observations of the Solar System are inconsistent with Newtonian
>     gravity with a speed-of-light propagation speed stuck in (this was
>     van Flandern's point, but he didn't understand enough general
>     relativity to realize that it didn't apply there);
> 4. observations of the Solar System are completely consistent with
>     general relativity, with speed-of-light propagation of gravity.
>
> Masochists can look at my technical paper on point 4,

> http://arxiv.org/abs/gr-qc/9909087.

Pretty interesting.

Do you follow the LIGO experiment? Do they have any data?

-
Rich

[Harry K]

On Sep 30, 9:26 am, Paul J Gans <gan...@panix.com> wrote:

> Mitchell Coffey <mitchelldotcof...@gmail.com> wrote:
> >On 9/29/2011 10:28 PM, John S. Wilkins wrote:

> >> Robert Carnegie: Fnord: cc talk-orig...@moderators.isc.org
> >> <rja.carne...@excite.com>  wrote:

>    --- Paul J. Gans- Hide quoted text -
>
> - Show quoted text -

That aside I find congress rather pleasureable. Wife may not agree.

Harry K

[Paul J Gans]

Amazing, isn't it?

[Paul J Gans]

Bob Casanova <nos...@buzz.off> wrote:
>On Fri, 30 Sep 2011 16:23:55 +0000 (UTC), the following
>appeared in talk.origins, posted by Paul J Gans
><gan...@panix.com>:

>>Walter Bushell <pr...@panix.com> wrote:

>>>In article <j632r3$q68$1...@dont-email.me>,
>>> Mitchell Coffey <mitchell...@gmail.com> wrote:
>>
>>>> Did Henry II have any sons who weren't bastards?

>>>Few are the monarchs that have sons that aren't bastards.

>>Back then, if you were not a bastard, you didn't last long.

>"Back then"? You must live a sheltered life, my son... ;-)

Most European monarchies have been relatively stable since
the 1600's.

One of the major, but usually unmentioned advantages of recognized
bastards (who were often granted titles and lands) is that their
power came from their father and later, the half-brother who
became king.

Thus they could usually be trusted not to sell out the monarchy
since nobody else would trust them.

As the medieval period waned, so did this advantage.

[Paul J Gans]

I believe that the general rule is that all fields have a particle
that "carries" them. Thus electromagnetic waves have photons.

[r norman]

Is that true of general relativity? Gravity has not yet been
integrated into the system of fields and force carrying particles. Of
course I am here arguing against myself and the case for gravitons,
but they are really have less reality now than, say, the Higgs boson.