Timeline for Can an "absolute" frame of reference be determined by measuring the compression of light?
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
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| Aug 15, 2012 at 20:41 | vote | accept | Robert Altman | ||
| Aug 15, 2012 at 11:51 | answer | added | Jonathan | timeline score: 3 | |
| Oct 20, 2011 at 19:24 | history | edited | Robert Altman | CC BY-SA 3.0 |
clarify question
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| Oct 20, 2011 at 17:32 | comment | added | David Z | Ah, got it. That last comment is a much better statement of your question; perhaps you could edit your original post so that it includes that phrasing? | |
| Oct 20, 2011 at 1:31 | comment | added | Robert Altman | Here is another way of looking at it: we know a moving sound source (such as a train) creates doppler shift, irrespective of whether or not anyone is in the "stationary" frame of reference. So, is it a reasonable conjecture to say that the Sun is creating doppler shift in light, irrespective of any specific observer or frame of reference? If so, that would seem to indicate that we could measure motion respective to an absolute frame of reference. | |
| Oct 20, 2011 at 1:07 | history | tweeted | twitter.com/#!/StackPhysics/status/126826804102168576 | ||
| Oct 20, 2011 at 0:28 | comment | added | David Z | OK, I kind of see what you mean. The thing is, all those motions are themselves relative. I'd guess that you're talking about something like measuring the Earth's motion relative to the universe as a whole. | |
| Oct 19, 2011 at 22:34 | history | edited | Robert Altman | CC BY-SA 3.0 |
clarification (compression of light equates with doppler shift)
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| Oct 19, 2011 at 22:32 | comment | added | Robert Altman | @DavidZaslavsky In hindsight, "compound" frame of reference probably isn't very clear. What I meant by that was the sum of all of the motions that we are a part of, such as: universal expansion + galactic rotation + solar orbit (this probably not a complete enumeration, just an example). | |
| Oct 19, 2011 at 21:50 | comment | added | David Z | @Zassounotsukushi: It's still not an absolute reference frame, though, just the rest frame of a particularly interesting object. Anyway, Robert: there are a couple of things I'm not clear on in your question. What do you mean by "compound frame of reference"? What physical phenomenon are you referring to as compression and elongation of light waves? | |
| Oct 19, 2011 at 21:34 | answer | added | Martin Beckett | timeline score: 5 | |
| Oct 19, 2011 at 21:11 | comment | added | Alan Rominger | Actually, you can do exactly this and do it with the cosmic microwave background. Someone offered that as an answer to a previous question I asked, I was rather surprised, but it makes sense. It can measure your velocity relative to the average velocity of matter when the big bang happened. | |
| Oct 19, 2011 at 21:02 | history | asked | Robert Altman | CC BY-SA 3.0 |