Timeline for Is there a contradiction of the theory of relativity here? -- Length contraction and EMR amplitude
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 26, 2011 at 19:34 | vote | accept | compman | ||
| Oct 26, 2011 at 16:46 | comment | added | user5800 | nope, read below. Whatever it is that you are referring by the amplitude of light, it is NOT a length and it doesn't simply contract along the direction of motion. | |
| Oct 26, 2011 at 16:30 | comment | added | compman | Colin K got it. So is that not how light works? | |
| Oct 26, 2011 at 13:28 | answer | added | user5800 | timeline score: 3 | |
| Oct 26, 2011 at 12:46 | comment | added | Ron Maimon | @ColinK: On further reflection, I think you are right--- this is a very difficult wrong idea to guess. I'll modify the answer. | |
| Oct 26, 2011 at 7:02 | comment | added | Ron Maimon | @ColinK: I don't think so--- this would be absolutely silly--- I am almost certain that he is thinking of the fact that the beam is deflected sideways when you move perpendicularly, so it isn't shining head-on, but at an angle. When you shine a flashlight (or laser) on a wall at an angle, as opposed to head on, it gets dimmer. This is a geometric effect of the beam spreading out, it is not as obvious that this spreading out doesn't apply in this case. I answered this version of the question. | |
| Oct 26, 2011 at 6:32 | comment | added | Colin K | I think he is thinking of light as a literal wave, the way people draw it on paper, so that length contraction perpendicular to the beam would reduce the height of the peaks. | |
| Oct 26, 2011 at 2:34 | comment | added | compman | I was thinking of travelling perpendicular to the beam of light. This wouldn't distort the wavelength or frequency of the light, just the amplitude (maybe). | |
| Oct 25, 2011 at 20:21 | answer | added | Ron Maimon | timeline score: 3 | |
| Oct 25, 2011 at 19:33 | comment | added | David Z | EM field amplitude transforms as a rank 2 tensor, so it's definitely not invariant. I think the power transmitted is invariant, though ($P = E/t$, and both $E$ and $t$ are timelike components of four-vectors). I'll come back to this and write up a proper answer later, when I have time, if nobody else has gotten to it first. | |
| Oct 25, 2011 at 17:18 | comment | added | Lagerbaer | Sounds like bdesham is right. The amplitude of an EM field is not a length, it's a field strength. My guess without having done any calculations: The EM field might get weaker, but since the area contracts as well, the beam is focused better so power might stay the same? | |
| Oct 25, 2011 at 17:10 | comment | added | bdesham | Are you confusing amplitude and wavelength/frequency? | |
| Oct 25, 2011 at 16:47 | history | asked | compman | CC BY-SA 3.0 |