the_ben_obiwan OP t1_irhdqhe wrote on October 8, 2022 at 3:58 AM

Reply to comment by Tremongulous_Derf in Are we watching distant galaxies the same speed they would actually be experiencing? by the_ben_obiwan

Thanks, seems to be the general consensus. I was just unsure if the great distance would exacerbated the effects, as in- if we watched the twin fly into the distance, they might appear to slow down, even though they moving at a constant speed because their clock would be slowing down, so their movement would also appear slower. I'm not really sure if that's how it works, its just interesting to think about

he_who_floats_amogus t1_irhfd1g wrote on October 8, 2022 at 4:17 AM

Great distance will greatly exacerbate the effects, because the entire universe is expanding. The reason why there's a limit to how far we can see is that there is an event horizon beyond which objects are moving away from us FTL. Relative velocity is proportional to distance.

We've confirmed this experimentally by observing distant cosmological events of known types. At a vast distance, we can observe events that literally function as a cosmological clocks, and can verify that they adhere to the expected time dilation. At a distance that results in relative velocity of 50% speed of light, you'll see events take 15% longer.