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Originally Posted by Sam5
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Originally Posted by Ut
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So he postulated the speed of light to be “c” relative to “empty space”, thinking that “empty space” was pretty much “stationary” with all the stationary and “fixed” stars.
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No. No no no no no. SR doesn't say anything about space. |
Here’s a direct quote of the original “constancy” postulate, from “On the Electrodynamics of Moving Bodies”, 1905:
”light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body.” |
Yes, yes. So what does that say about space? Nothing. Rather, it says that the speed of light is a definite, constant value c in the absence of any medium.
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You should say “atomic clock rate”. The Lorentz-force atomic clock rule, as used by Einstein, applies to atomic clocks only, i.e. to atomic oscillation rates. It does not apply to pendulum clocks, mechanical clocks, balance wheel clocks, thermodynamic clocks, etc., etc.
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I'd love to know where you got the idea that clocks could be fundamentally different from each other. They are measurers of time. That's what makes them a clock.
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Well, tell us what you found out from your experiment.
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That -- surprise, surprise -- a wire moving through a magnetic field has a current induced inside it, which induces a magnetic field around it, which opposes the motion of the wire through the field. This "urban legend" is taking place in high school and undergraduate physics labs the world over.
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No, the stronger the field, the more slowly light propagates, and the stronger the field the more slowly the atoms oscillate, and they emit light at a lower frequency. The “redshift” occurs as the light is being emitted by a slowly oscillating atom. The slow speed of the light emerging from a gravity well does not contribute to the redshift. The light is emitted already redshifted. Read Einstein’s 1911 theory about this. He explains it.
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Because you're obviously an observant and well read individual, I'll assume that you simply misinterpreted the idea behind changing the colour of the text there, and saying 'forget that bit, I was wrong'.
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Do you know who called it the “aether” first, in relation to gravity fields? Do you know who first said that light beams will bend when they pass near astronomical bodies? Do you know who said that the “gravity fields” are responsible for such bending?
Newton.
Read his “Optics”, 1704 edition.
Geepers! Go to a big library and read some good books, instead of getting all your information off the internet. Turn your computer off and go to a library.
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Strangely, I
did know that Newton called it the aether. I also know that people respectfully spell it "aether" because there's a group of chemicals known as "ethers". See that? Applied knowledge!
Newton's theory was that light particles had mass, with red being the most massive. Thus, any beam of light passing through a gravitational field should be spread out into its spectrum. From what I understand of GR, though, this prism effect shouldn't be observed since the geodesic should be the same at all wavelengths. At least, that's the preconception I'll be taking into my GR class next semester.
Oh, and geepers! Learn how to interpret theories, instead of just pulling quotes from papers and books.
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Einstein was a little surprised in 1911 when he discovered that the gravity fields in space could control the local speed of light through them. It was after this that he started talking about the “ether” qualities of gravity fields.
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No, Einstein was surprised that gravitational fields could ACCELERATE light. The speed of light, however, remains constant in these fields. It merely changes directions. Ricimer explains what Einie meant by "ether qualities".
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Although he called space “empty” in his 1905 theory, in the 1952 appendix to his 1916 book he said:
”There is no such thing as an empty space, i.e. a space without field.”
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That's right. There is no such thing as empty space. There's not even such thing as a vacuum. Quantum Mechanics tells us that we cannot guarantee a vacuum. But the presence of fields in space do not alter the speed of light, and the spacing of atoms in "empty" space is such that no optical effects are found.
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By then he knew that the gravity fields of space have some influence on the local speed of light.
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I'd love to see you explain this line.
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There is quite a big difference between his “empty space” opinion of his 1905 theory and his “no empty space” opinion of 1952. He had learned a lot during those 47 years.
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No there's not. The electric field was known of years before 1905. Faraday discovered it in the 1820s. He even assumed that it was infinite in span. So Al couldn't have meant that space had no fields in 1905. His revision is probably just a note, enforcing the idea that fields exist everywhere, even in a vacuum.
Here's a question for you: You stated earlier that redshifts occur due to slowly oscillating atoms. Why are they oscillating slowly?