Timeline for How does wind speed affect the velocity of light?
Current License: CC BY-SA 3.0
10 events
| when toggle format | what | by | license | comment | |
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| Dec 5, 2020 at 19:31 | comment | added | Christopher King | @binaryfunt the velocity formula applies to reference frames in general. There do not even need to be objects involved, only reference frames. | |
| May 31, 2014 at 2:16 | comment | added | Brian Moths | @BrianFunt No that is not a coincidence. If you have a one dimensional set of space-time events described by $dx/dt = v$ in some coordinates, and then you used primed coordinate which are boosted by a speed $u$, then the $dx'/dt'$ will be equal to the boosted speed. This is just due to the geometry of space-time. It is true independently of whether the set of events is the worldline of a particle or the wavefront of light or just an arbitrarily chosen path through spacetime. | |
| May 30, 2014 at 21:16 | comment | added | binaryfunt | Is it just coincidental that the group velocity of light is being treated similarly to an 'object' moving at speed $v$? | |
| May 30, 2014 at 20:58 | comment | added | Brian Moths | @BrianFunt I think I should have explained this better. Basically imagine you are standing on train tracks with the wind blowing at some speed $u$. Now you are wondering what the speed of light is. Luckily your friend is coming by on a train moving at the same speed $u$. You ask him what the speed of light is, and since he sees no wind the answer is easy: $v=c/n$. Now we have the light moving at a speed $v$ in a frame which is moving at a speed $u$ with respect to $u$, and we want to know what is the velocity in your frame. The asnwer is given by the relativistic velocity addition formula. | |
| May 30, 2014 at 18:26 | comment | added | binaryfunt | Is there a reason why velocity addition applies to light in a moving medium? | |
| May 2, 2014 at 20:52 | comment | added | Brian Moths | That's a good point. In reality wind is not just a uniform motion of air at a constant speed. The pressure and temperature will be non-uniform, and this will cause the index of refraction to be non-uniform. This effect on the speed of light is probably greater than the effect I talked aobut in my answer. However, it is not as easy to get a clean answer as to what the speed of light should be with these effects taken into account. | |
| May 2, 2014 at 20:25 | comment | added | jinawee | Wouldn't turbulence and preassure be relevant for the refractive index? | |
| May 2, 2014 at 19:15 | vote | accept | Christopher King | ||
| May 2, 2014 at 19:15 | review | Suggested edits | |||
| May 2, 2014 at 19:21 | |||||
| May 2, 2014 at 17:44 | history | answered | Brian Moths | CC BY-SA 3.0 |