When we observe a galaxy farther than 13 billion light years away, we see that galaxy as it was 13 billion years ago. But back then, that galaxy was much closer to us ,if indeed we live in an expanding and accelerating universe. The question is, why we see it so far when in fact it was very close to us and the time for the light to reach us was much shorter?
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Have a look at this timeline of the universe:
The x axis is the time axis. After the "dark ages" there are galaxies formed, which become diluted in space as time grows.
The question is, why we see it so far when in fact it was very close to us and the time for the light to reach us was much shorter?
Because light has to travel a larger distance than when the universe was more restricted. If we existed at the formation of the two galaxies it would have taken less time to see the galaxy. We exist now, and the photons that reach us now have to travel the larger distance even though they left at a time when it was close to our galaxy because the distance was expanding.
Take the expanding balloon with dots on it. The distance between dots changes with time as the balloon expands. The photons are just a ruler measuring the expanding distance, imo.
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