- #1
fbs7
- 345
- 37
Hello there!
Sorry for the dumb question, but for years I have been very curious and confused about this: I just read that they discovered a galaxy 13.7 Bn light-years away -- therefore its light was emitted 13.7 Bn years ago and traveled 13.7 Bn light-years in some line.
But, 13.7 Bn years ago, the universe was only 750 M years old - so if Earth had existed by then the visible universe had a radius of at most 750 M light-years and that galaxy would be at most 750 M light years away.
So, either the light made several "loops" around (what sounds silly), or the visible universe was bigger than 750 M light-years when it was only 750 M light-years old (what also sounds silly), or that galaxy was not in the visible universe by then and now it is (what sound even sillier).
So how come its light took 13.7 Bn years to travel a distance that was at most 750 M light years? Where have these photons been all that time?
Sorry for the dumb question, but for years I have been very curious and confused about this: I just read that they discovered a galaxy 13.7 Bn light-years away -- therefore its light was emitted 13.7 Bn years ago and traveled 13.7 Bn light-years in some line.
But, 13.7 Bn years ago, the universe was only 750 M years old - so if Earth had existed by then the visible universe had a radius of at most 750 M light-years and that galaxy would be at most 750 M light years away.
So, either the light made several "loops" around (what sounds silly), or the visible universe was bigger than 750 M light-years when it was only 750 M light-years old (what also sounds silly), or that galaxy was not in the visible universe by then and now it is (what sound even sillier).
So how come its light took 13.7 Bn years to travel a distance that was at most 750 M light years? Where have these photons been all that time?
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