Originally Posted by nstygma
does our ever changing position in space relative to the objects in question get accounted for in the calculations? how does the Doppler effect come in to play? over those great distances and great amounts of time, how does our own speed relative to that observed light affect time dilation? if you have a good link that would be great, save you some typing
A) Yes and no, The distances things move in our lifetimes is so minute as to not be needed for inclusion
B) Doppler (or red shift) shows the speed at which the object is moving away from us. Or in the case of M31 toward us
C) No it doesn't when something is 125,000,000,000,000,000,000 miles away, us moving through space even at light speed would not change the perceived distance to another galaxy. Said another way, 100 light years (a lifetime of traveling at light speed) is within the margin of error of something 30,000,000 light years away.