Rotating Disk Method to Attain Light Speed?

[PeterDonis]

I wonder... what's the speed of sound in unobtainium?

It can't be greater than or equal to the speed of light--that's the ultimate relativistic limit, even for unobtainium, superbium, idealmaterialium, etc.

 

[Jaime Rudas]

I wonder... what's the speed of sound in unobtainium?

Sound doesn't propagate through the unobtainium.

 

[FactChecker]

Well, we don't have an actual test lab here, so all we can tell you is what the theory says.

Particles have been accelerated to near the speed of light, so it is known how much energy and force is needed. The results agree with the theory to an impressive degree.

 

[Ibix]

Particles have been accelerated to near the speed of light, so it is known how much energy and force is needed. The results agree with the theory to an impressive extent.

Bertozzi even filmed a simple test of this, and somebody put it on YouTube:

 

[aLeaf]

We've already given you the results that this lab produces--they're the results that relativity predicts.

That’s fine... Everyone has their limits, and an actual test would not be feasible. Thanks and best wishes to you...

 

[aLeaf]

Experimentally, rotating disks break apart when their tangential velocity is on the order of the speed of sound in the material. Even the speed of sound in diamond is not relativistic, let alone close to c.

Thanks. This is useful, practical information.

 

[aLeaf]

Perhaps one of the first to analyze this situation was Paul Ehrenfest in his 1909 paper "Uniform rotation of rigid bodies and the theory of relativity" which is why it is now called the Ehrenfest paradox.

Thanks for sharing the paper. Unfortunately, I don’t read German, but Google Translate was able to make some sense of the text.
"Now, in a recently published work1) a definition of the relative rigidity, which makes all possible movements. Mr. Born has Definition - the basic idea of the Relati- theory - not to the system of measurement of a stationary observer, but on the (Minkowski) standards moods, so to speak, of a continuum of infinitesimal observers who are connected to the points of the unevenly moving body. ' each of them shall in his or her own measure its infinitesimal environment..."
Do you have any more pages, or a link to the full article?

 

[aLeaf]

Thanks for sharing the paper. Unfortunately, I don’t read German, but Google Translate was able to make some sense of the text.
"Now, in a recently published work1) a definition of the relative rigidity, which makes all possible movements. Mr. Born has Definition - the basic idea of the Relati- theory - not to the system of measurement of a stationary observer, but on the (Minkowski) standards moods, so to speak, of a continuum of infinitesimal observers who are connected to the points of the unevenly moving body. ' each of them shall in his or her own measure its infinitesimal environment..."
Do you have any more pages, or a link to the full article?

Ahh, just found a translated version!
https://en.wikisource.org/wiki/Tran..._of_Rigid_Bodies_and_the_Theory_of_Relativity
Hopefully it’s accurate, at least relatively speaking...

 

[aLeaf]

As Peter has pointed out, in this thread all you can do is apply the theory. You can call this "doing a thought experiment" if you like, but it's still just applying the theory. And the theoretical implications of relativity are clear - the kinetic energy of the disc depends on the linear speed of its parts and diverges as you approach $c$, as do the stresses on the disc. So the disc will disintegrate, and even if you just pretend it won't disintegrate it still can't reach $c$ because no amount of energy is sufficient.

You would need to do a real experiment and show that its results are inconsistent with relativistic predictions to challenge this.

Not interested in challenging the established theory, actually. To quote you, "just applying the theory" is not likely to provide any insights beyond those allowed within the theory. Fortunately, theories are imperfect, hence cannot support absolute statements of negation. Innovation tends to require re-examination of fundamental precepts, like the early geocentric concepts of astrophysics and its "perfect" crystal spheres.

 

[berkeman]

Thread is closed for Moderation...

 

[PeterDonis]

Not interested in challenging the established theory, actually.

Um, yes, you are:

To quote you, "just applying the theory" is not likely to provide any insights beyond those allowed within the theory. Fortunately, theories are imperfect, hence cannot support absolute statements of negation. Innovation tends to require re-examination of fundamental precepts, like the early geocentric concepts of astrophysics and its "perfect" crystal spheres.

This is challenging the established theory--just with nothing to back the challenge up but vague generalities.

Thread will remain closed.