I don’t really understand it, could someone explain in basic terms?
Are we saying if a star is 120 million lightyears away, light from the star would take 120 million years to reach us? Meaning from the pov of time on earth, the light left the star when the earth was still in its Cretaceous period?
In: 292
A light year is the distance light can travels in a year. It doesnt teleport to one place to another, after all. So if you’re looking at an object 1 light year away, you’re seeing light that has traveled 1 year to get to where you are, so in a sense you’re seeing the object as it was last year. Anyone looking at Earth right now from 300 million light years away, is currently seeing the dinosaurs, because the light that was emitted from Earth then is just now reaching them.
Edit: one consequence of this is that, if the sun were to disappear now, we wouldn’t know for 8 minutes. Also, for huge distances, it might take longer than the pure light year distance, because of the expansion of the Universe.
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