- #36
NoahsArk
Gold Member
- 249
- 22
I've ordered the Asimov and Pais books. Thank you for the suggestions.
NoahsArk,NoahsArk said:I've ordered the Asimov and Pais books. Thank you for the suggestions.
Time dilation was proposed by Joseph Larmor in 1897 after George Fitzgerald announced the idea of length contraction in 1889. They and Hendrik Lorentz were trying to explain why luminiferous aether could not be detected, and why the speed of light was frame-independent.NoahsArk said:... the most profound part of special relativity is that the passage of time between any two things happening is not the same for everyone, and depends on their relative motion.
David Lewis said:Time dilation was proposed by Joseph Larmor in 1897 after George Fitzgerald announced the idea of length contraction in 1889. They and Hendrik Lorentz were trying to explain why luminiferous aether could not be detected, and why the speed of light was frame-independent.
The whole of special relativity is implicit in the structure of Maxwell's equations. But up until Einstein, no-one realized that the incompatibility of Maxwell's equations with Galilean relativity (and hence Newtonian physics) was a problem with Newton and Galileo, not with Maxwell. Einstein seems to have been the first to realize that you could shouldn't regard (what we now call) the Lorentz transforms as a mysterious mathematical patch for Maxwell, but rather that they are a replacement for the Galilean transforms.NoahsArk said:Is it correct to say that the evidence was there before, but he took the leap of faith before anyone else to come to that conclusion?
This is a somewhat inaccurate description of the equivalence principle. That principle is, however, a key insight that leads to the possibility of modelling gravity as spacetime curvature.NoahsArk said:I was just reading in an article that his other key insight was that acceleration and gravitation are two ways of describing the same force.
NoahsArk said:One of Einstein's key insights, that he got while walking with his friend Michele Besso, is that time is in fact different in different frames.
NoahsArk said:I was just reading in an article that his other key insight was that acceleration and gravitation are two ways of describing the same force.
Ibix said:But up until Einstein, no-one realized that the incompatibility of Maxwell's equations with Galilean relativity (and hence Newtonian physics) was a problem with Newton and Galileo, not with Maxwell.
PeterDonis said:"Time is different" is ambiguous.
Yes. More specifically that Maxwell’s equations were only valid in the rest frame of the aether.NoahsArk said:Were others thinking that Maxwell was wrong
Wrong is too strong a word, IMO - the equations clearly worked. The problem was that they were not invariant under the Galilean transforms, which suggested (as Dale observes) that they were missing some terms (small ones, because they worked well enough as was) related to your velocity relative to... something, which got christened "aether". The outcome of Michelson-Morley led to Fitzgerald contraction and eventually Lorentz' transforms. But as far as I understand, the latter were treated as a relationship between Newtonian time and space coordinates and the x and t parameters in Maxwell's equations (which everyone had regarded as position and time).NoahsArk said:Were others thinking that Maxwell was wrong
NoahsArk said:Were others thinking that Maxwell was wrong (and also that the results of Michelson and Morley's experiment were wrong) because the speed of light can't be constant without contradicting Newton and Galileo's statements that time is absolute?
That's just a consequence of taking the finite constancy of light seriously as he did together with the relativity postulate that rejects unique privileged rest frames like the aether. Once it was empirically clear that the speed of light was not infinite it could either depend on the sources privileging some frame or else follow a relativity principle like the galilean but with a finite speed of light instead(Einstein way).Mister T said:The notion of the speed of light being independent of the speed of the source was something that Einstein came up with, as far as I know.
Tendex said:That's just a consequence of taking the finite constancy of light seriously as he did together with the relativity postulate that rejects unique privileged rest frames like the aether.
What did you think "taking the finite constancy of light seriously " mean here?Mister T said:Einstein was careful to state his 2nd Postulate as an assertion that the speed of light is independent of the speed of the source. It's not a consequence in his theory, it's a postulate.