How fast is gravity?

[fuhrerkeebs]

Obviously it means that it cannot be instantaneous, but you specifically mention gravity traveling to earth in 8 minutes, but that is not what you demonstrated in your explanation.

[ydoaPs]

in what way?

[fuhrerkeebs]

here is a simple explaination. information cannot travel at speeds above c.

 

Your explanation only demonstrates that it is only possible for gravity to reach the earth in greater than or equal to 8 minutes.

[ydoaPs]

really? i took this directly from my simple explaination

 

(gravitons, if they exist, are believed to travel at c)

 

it kinda says 8 minutes. :Þ

[fuhrerkeebs]

Exactly, it kinda says 8 minutes. The main thing to look at in that sentence is "if they exist." No one has observed one, there is no proof they exist, and the only reason they were though of in the first place was for the purpose of symmetry. AlGore was asking for proof, and proof requires the use of established theoroms.

[ydoaPs]

well, you cannot PROVE anything. there is no proof that you exist. your posts could be created by a bot or even my own imagination. for all i know, the entire universe could be my dream.

[fuhrerkeebs]

Hahaha this caught me off guard. Don't you think it is a little immature to resort to Kantian philosophy when backed into a corner? You know what was meant by proof, you're not that stupid.

[algore]

Edward Duffy, thanks for your input .. I'd never heard of tensegrity and am not too inclined to study it, since it appears to contradict some pretty well-established facts. There are a lot of alternate theories out there which, if true, would turn modern physics upside down; some are much better supported than this one, and perhaps I'll discuss them on this forum another time. As I mentioned above modern physicists have gotten far ahead of actual experimental verification, leaving the field wide open to far-out speculations .. one of which might actually be correct. Many of the brightest physicists today have (in my opinion) "fallen in love" with their theories and therefore have closed their minds to these alternatives; that's unfortunate. Still, (if you want my advice) make sure you are familiar with the accepted facts before speculating; otherwise you invite ridicule.

[ydoaPs]

what corner? i am not backed into anything.

[fuhrerkeebs]

Which would imply that you actually did not what is meant by proof in physics. Wow...

 

A quick refresher: A proof is anything that proves a conjecture correct using well-established theoroms. Your proof didn't work. Gravitons are conjecture, not well-established theory.

[ydoaPs]

hold on didn't we have the same answer to the question? then why are you trolling?

[fuhrerkeebs]

I was merely pointing out that your answer wasn't based on an actual proof.

[fuhrerkeebs]

Ah, let's quit it...we're obviously not going to convince each other of the others viewpoint...and I'm damned tired...

[ydoaPs]

it wans't supposed to be.

 

KISS

 

Keep

It

Short and

Simple

 

there are several people (citing the invasion of the 14 yr. olds and multitudes of "i have no training in science or math") that would have no clue if i had a post full of equations, so i merely provided a short, simple concept showing why it cannot be instantainious.

[algore]

yourdadonapagos, there are two problems that I can see with your "proof" (I put the word in quotes out of respect for Kant .

 

First, the restriction on speed of information is only a principle, or theory. You can't use a theory to prove an experimental fact; instead, it's the other way around. When I first asked this question, years ago, I argued (correctly) that gravity speed was still an open issue. Of course, as mentioned above, it turns out we now have experimental proof that it's limited to c (1.06 c, to be exact). This constitutes more (real) proof that the theory of limited informational speed is correct. However, suppose some new "fifth force" were discovered - then we can't just assume it's limited by c because an existing theory says it ought to be; instead we'll have to verify it experimentally, thus making the theory even more certain. I'm sure Kant would agree!

 

Second, you have to show that even if gravity were instantaneous, we could use it to actually convey information. I won't go into that issue since it's become a moot point; if we ever get to a "fifth force" I'll be happy to revisit some of the complications involved. A related issue is quantum non-locality - at first glance it seems to violate the restriction on speed of information but detailed analysis shows that it doesn't. The point is that you have to do that detailed analysis to finish your attempted proof.

 

Thanks again for your input .. and thanks also for yours, fuhrerkeebs. I can see you're a valuiable resource and will return in the future with some more dumb questions!

[Cap'n Refsmmat]

hold on didn't we have the same answer to the question? then why are you trolling?

I may not be a moderator, but I'd like to say something here:

You are the one trolling. You make a post, supposed to prove a point, that's based on a theory with no evidence to support it whatsoever. Then you say that is proof. Unless you're Jean Chretien ( "A proof is a proof. What kind of a proof? It's a proof. A proof is a proof. And when you have a good proof, it's because it's proven.") you really shouldn't say that.

And then arguing that it's the easy way and you might befuddle him with a complicated answer is just dumb, because a previous answer with a good explanation did not baffle him.

Please don't waste our time like this.

[ydoaPs]

i never said it was proof.

 

my post was based on common information, therefore i didn't need to cite proof.

[Cap'n Refsmmat]

i never said it was proof.

 

my post was based on common information' date=' therefore i didn't need to cite proof.[/quote']

Can you justify your answer by solving GR equations?

[ydoaPs]

as i said before, it was for the multitudes of people that start their posts with "i have no training in math or science..." and for the invasion of the 14 year olds.

[swansont]

Which would imply that you actually did not what is meant by proof in physics. Wow...

 

A quick refresher: A proof is anything that proves a conjecture correct using well-established theoroms. Your proof didn't work. Gravitons are conjecture' date=' not well-established theory.[/quote']

 

Is General Relativity not considered well-established? It predicts that gravity acts at c. There was an experiment about 2 years ago, though there was criticism that the results weren't interpreted properly.

[algore]

Yes, swansont, GR <i>predicts</i> that that gravity acts at c but the underlying point of my question was that prediction is not proof. Proof must ultimately come from experiment (according to Sir Francis Bacon, who invented the scientific method, and also according to common sense). If you review the actual experiments which ratify GR, none of them depends on the speed of gravity - that is, until the recent one 2 years ago that you cite (which I stupidly had overlooked; I should have googled before posting). I'm pretty sure one could formulate an "alternate GR", allowing instantaneous gravity, which is compatible with all those experiments (but don't ask me to do it). Perhaps I should have made my underlying point explicit but I "cleverly" intended to let someone answer something like "GR predicts gravity acts at c" and then make the above argument.

 

Now the focus shifts to the Formalont-Kopeikin experiment. Could you please give a link to the "criticism that the results weren't interpreted properly"? Perhaps this is still an open question after all.

 

Just to clarify, I don't doubt that gravity really does act at light-speed; that's been pretty obvious for many years. I was just playing devil's advocate - legitimately, I think. Accepting "obvious", but experimentally unconfirmed "truths" has been the bane of science many times in the past few centuries.

[fuhrerkeebs]

Is General Relativity not considered well-established? It predicts that gravity acts at c. There was an experiment[/url'] about 2 years ago, though there was criticism that the results weren't interpreted properly.

 

I was referring to yourdadonapogosticks proof when I said his proof did not use well-established theoroms...if you were not posting to me, then please ignore

[swansont]

Yes, swansont, GR <i>predicts</i> that that gravity acts at c but the underlying point of my question was that prediction is not proof. Proof must ultimately come from experiment (according to Sir Francis Bacon, who invented the scientific method, and also according to common sense). If you review the actual experiments which ratify GR, none of them depends on the speed of gravity - that is, until the recent one 2 years ago that you cite (which I stupidly had overlooked; I should have googled before posting). I'm pretty sure one could formulate an "alternate GR", allowing instantaneous gravity, which is compatible with all those experiments (but don't ask me to do it). Perhaps I should have made my underlying point explicit but I "cleverly" intended to let someone answer something like "GR predicts gravity acts at c" and then make the above argument.

 

Let me preface this by saying that GR is not my area. But I think that there is a binary pulsar observation, where they measure the orbit decay that is predicted by GR, and gravity radiation is predicated on gravity not being instantaneous; further, I believe the results are consistent with the speed of propagation being c with a high degree of precision.

 

I think that any GR that had instantaneous propagation would run afoul of that observation. But feel free to try.

 

As for "A quick refresher: A proof is anything that proves a conjecture correct using well-established theoroms. Your proof didn't work." Theorems and proofs are math, not science. But I concede that gravitons are not part of GR; I was reading it more generally (as it were).

 

 

 

Now the focus shifts to the Formalont-Kopeikin experiment. Could you please give a link to the "criticism that the results weren't

 

Here you go

[Crash]

I didnt have time to read the whole thread but according to "the elegant univese" (String theory) Gravity acts at c.

[JHAQ]

Gravity travels at light speed as per Einstein who revolutionized Newtons concept that it was instantaneous .