- #1
wolram
Gold Member
- 4,267
- 557
Is it true that the speed of light is only dependent on the size of the universe, if the universe were much smaller would the speed of light be faster?
Not according to our best current measurements. As far as we can tell, the speed of light is constant and does not depend on the size of the universe.Is it true that the speed of light is only dependent on the size of the universe
These models are speculative and do not have any experimental data in their favor at this point.
Where did you read this?Is it true that the speed of light is only dependent on the size of the universe, if the universe were much smaller would the speed of light be faster?
This particular theory was debunked by Bill Anders.Ranks right up there with the green cheese moon theory.
Has the wavefunction collapsed yet?Surely the cheese could be both American and green without violating any known laws?
It will in about 10 minutes, my girl friend has advised me so. Goodnight.Has the wavefunction collapsed yet?![]()
This doesn't make sense as you state it, because the "consequences" of a Lorentz transformation depend on the value of ##\gamma##. Different ##\gamma##, different consequences.If the value of c changed, but was the same throughout the universe over small ranges of time, meaning any experiment I could do would return 'c' as the speed of light, we would end up with the same lorentz transformation and same consequences, just with a different value for gamma.
Unless you have an actual acceptable reference describing a theory that shows this, I would be very careful making such claims. Certainly standard SR (or GR) is not such a theory.If c changes, then so will the numerical value of gamma, but time dilation between frames is still a thing.
Same comment as above. Please bear in mind the PF rules about personal theories.Interestingly, though, is that this implies a "god frame" so to speak. An "absolutely stationary" frame in which the size of the universe is measured in order to determine c.
The Wikipedia article you linked to earlier talks about speculative models predicting a variable speed of light (more precisely a variable fine structure constant). But we don't know if those are what the OP was asking about; he hasn't said.I linked to "variable speed of light theories" previously, and that is what this thread is about, no?
You're not even talking about them, as far as I can see. You're just waving your hands about what you think some imaginary theory in which ##c## varies might look like. What you should be doing, if you're really interested in the (speculative) theories along these lines already advanced, is to read the actual papers proposing them and see what they say, and then base your discussion on that (with references).I'm not advocating for the theories
Reminds me of a "game" some college students made where the value of c was much, much smaller. Something like 10 mph or something. The player controlled a character who had to walk/run around and perform some (usually) trivial tasks. But with the reduced speed of light, relativistic effects were very noticeable, making these trivial tasks not so trivial anymore.If c changes, then so will the numerical value of gamma, but time dilation between frames is still a thing.
You're right, I just assumed and since I wasn't ever corrected, assumed that to be the case.But we don't know if those are what the OP was asking about; he hasn't said.
I suppose it is a little bit out there. I'm assuming that the observational consequences of SR still need to be intact. In the ways that I know how to derive the Lorentz transformations via light clocks and the like, at any value of t in some frame, if an observer measures c in that frame and then in another, nearly-simultaneously for the observer in question, they will notice that time and length are both distorted. The postulates of SR, in fact, do assume that "c is constant". However, in practice, it doesn't seem to be utilized as strongly. "c is constant" means, to me, constant through both space and time. It seems to be used meaning constant through space. This may or may not be the case with GR. I'm not very far into GR as of right now.You're not even talking about them, as far as I can see. You're just waving your hands about what you think some imaginary theory in which ##c## varies might look like. What you should be doing, if you're really interested in the (speculative) theories along these lines already advanced, is to read the actual papers proposing them and see what they say, and then base your discussion on that (with references).
Yes, you are. Please look at the actual papers.I might be spouting off again.
In progress...Yes, you are. Please look at the actual papers.
...Joao Magueijo said:This remark was clearly made by Bekenstein [11], who pointed out that the “observation” of a varying dimensional constant is at best a tautology, since it relies on the definition of a system of units.
However, in his example, the meter was defined in terms of c. Of course c is constant if c is defined as a function of c!Joao Magueijo said:it is always possible to define units such that c remains a constant.