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Speed of light not the upper limit

Snick

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Astronomer said:
Oh, absolutely. I would never argue to the contrary. But aether didn't actually appear to exist. It was merely presumed to be necessary for the propagation of light. And please don't get me wrong, here: I believe that at the time, it was a perfectly valid assumption to make, and a perfectly valid theory to test.
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The idea that there was some sort of medium through which light went was based on observations. Newton originally thought that light was composed of particles, but it was found that light also behaved like waves, so something had to be put there for the waves to flow through. It still is a valid theory, and someone should actually ttest it.

No, there's not. (Are you sure you're not still talking about aether here?) But there is considerable elegance in running an existing theory through all its conditions and having something utterly surprising fall out of the math -- like black holes, or new particles -- only to be confirmed later by observation. That's the elegance I'm talking about. Aether theory is rather the opposite of that, though we certainly couldn't have known that at the time. Live and learn.
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I was thinking of some of the more mathmatical models that come up with "dimensions" that are curld in on themelves. I believe that some versions of string theory have 11 dimensions. There are other such things that probably are simply accidental results of math to which Ocam's Razor was not put.
 

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Maxx said:
Light (which in common use means huge numbers of photons) does various things that look like waves, but the actual light particles as single units move through empty space like any particles. So there is no medium required to explain how light particles move through space.
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And why not call it a mediu, if it acts like one?

There is ver little difference between space=time and aether. The biggest difference is the name. If Einstein hadn't assumed that there couldn't be an inertials fram of reference, or if someone had immediately said: "Fine, aether isn't an inertial frameof refernece.", then the term aether might be the current for space-time.
 

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benbradley said:
What's the difference between quantum mechanics and normal space?
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There is no necessary difference. I was using the terminology that Maxx used in refernece to what is something called "quantum foam".

This was the original justification for the hypothesis of ether/aether, that because mechanical waves go through a medium, that electromagnetic waves must also have a medium to travel through.
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Yes, and it still is a perfectly reasonable point. I don't think that anyone has explained waves in a way that does not require a medium of some sort.
 
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Snick said:
I don't think that anyone has explained waves in a way that does not require a medium of some sort.
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It might be useful to distinguish between media strictly speaking and other things and between waves strictly speaking and things that have wave-like characteristics.

So: spacetime is not a medium in the same way that water and air are media that translate sound.
AND: light waves and gravity waves are not waves in the same way that sound waves are waves.

There are analogies, and you can find many aether-like and wave-like things about spacetime, light and gravity, but light is made of photons which are essentially particles and spacetime is not (strictly speaking) a medium, but a series of topologies and coordinate systems that are used to look at interactions and fields.
 

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Maxx said:
It might be useful to distinguish between media strictly speaking and other things and between waves strictly speaking and things that have wave-like characteristics.
Click to expand...

Yes, being to differentiate things is a good idea.

So: spacetime is not a medium in the same way that water and air are media that translate sound.
AND: light waves and gravity waves are not waves in the same way that sound waves are waves.
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Space-time is not a medium; that is not among the characteristics that it is defined as having.

While gravity waves are not transverse waves on water, they appear to be compressional waves like sound waves.

Light is different, and I think that it is uncertain whether it travels un waves, but, if it does, then it uses transverse waves. Those waves are not completely like waves on water, but they doo act like transverse waves in some medium.

There are analogies, and you can find many aether-like and wave-like things about spacetime, light and gravity, but light is made of photons which are essentially particles and spacetime is not (strictly speaking) a medium, but a series of topologies and coordinate systems that are used to look at interactions and fields.
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Yes, and space on the smallest scale is something lese, but we don't know what. Strictly speaking space-time is simply a theoretical thing that is defined as having certain characteristics. It has all of the characteristics of aether, except that it is not the medium through which light waves moves. The more I think about the more intriguing the whole matter becomes.
 
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brkingsolver said:
I believe there is some concern that their measurements are a result of faulty equipment.
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I heard on the radio recently that the person who headed the group had resigned. It would have been more interesting if someone had confirmed the results.
 
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I found that story:

Leader of Controversial 'Faster-Than-Light' Physics Experiments Resigns
http://www.voanews.com/english/news...ht-Physics-Experiments-Resigns-146020965.html

If another group had confirmed the results, there would be a lot of scrutiny of both experiments, especially of the techniques and equipment they have in common, and replication by yet others using the least amount of common equipment and techniques possible, as it would STILL be a very doubtful conclusion and a continued strong suspicion in experimental error. After all, it's an extraordinary claim.
http://en.wikipedia.org/wiki/Marcello_Truzzi#.22Extraordinary_claims.22
 

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It isn't really an extraordinary claim. While there are some theories that require that the speed of light be the maximum speed that anything could be accelerated to, there may be other explanations for the same phenomena that would not require that. I'm just hoping that the universe is even stranger than it seems
 

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Snick said:
It isn't really an extraordinary claim. While there are some theories that require that the speed of light be the maximum speed that anything could be accelerated to, there may be other explanations for the same phenomena that would not require that.
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There's exactly one theory, supported both by vast amounts of scientific observation, and by solid mathematics, that supports the theory that the speed of light is the limit beyond which no physical material can be accelerated. There exist exactly zero explanations from realistic physics which suggest otherwise. Faster-than-light travel remains a science-fiction concept, and nothing more.

caw
 
RichardGarfinkle

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Snick said:
It isn't really an extraordinary claim. While there are some theories that require that the speed of light be the maximum speed that anything could be accelerated to, there may be other explanations for the same phenomena that would not require that. I'm just hoping that the universe is even stranger than it seems
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It's actually a very extraordinary claim. Relativity is as pointed out confirmed by a lot of observation (and nowadays experimentation). Special relativity predicts a number of changes in characteristics of objects as they move faster (these are the characteristics as they are observed by other objects).

There is a single factor used in these changes. This quantity is either multiplied by the characteristic (length is multiplied for example) or divided (mass is divided). The quantity is

Sqrt(1 - v[SUP]2[/SUP]/ c[SUP]2[/SUP])
Where sqrt is sqrt, v is the object's speed and c is the speed of light.

When v is greater than c this quantity becomes imaginary which is essentially meaningless in the context of our physical universe. And, in order to get to these imaginary quantities the objects have to accelerate through c, a speed where they would have infinite mass and no length.

This isn't to say it's impossible only that the claim is extraordinary and requires a whole lot of proof before tearing down the entire structure of relativity.
 
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