Light is NOT constant relative to the source.

[glover_m]

Homework Statement

Homework Equations

How do you come up with 2ud/(c^2-u^2)

The Attempt at a Solution

Here's my issue with this problem: I would expect that for the light from A1 to reach Earth it would be d/u-c, and the time for the light of A2 to reach Earth would be d/u-c + T/2 = d/(u-c)
+ pir/u

Therefore Delta A would be (pi)(radius)/u

This isn't the case however, am I missing something? Shouldn't the difference in times be equal to half the period of rotation?

 

[willem2]

Here's my issue with this problem: I would expect that for the light from A1 to reach Earth it would be d/u-c, and the time for the light of A2 to reach Earth would be d/u-c + T/2 = d/(u-c)
+ pir/u

shouldn't it be d/(u+c) from A1, since the star is moving towards the earth.
If you use that you get the difference from your text.