Ancient galaxies: lack of mergers vs. subsequent spatial expansion

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Has anyone had success in disentangling the phenomenon of galaxy mergers from that of spatial expansion in explaining the fact that distant galaxies are closer together?
Galaxies far away---that evolved soon after the Big Bang---are reported to be closer together than the galaxies we observe near us. This could be due to two distinct reasons. One is that relatively nearby galaxies, over time, tend to merge, and the ones we see from far away haven't had time to coalesce yet. The other reason is that the assumed spatial expansion of Big Bang Theory hadn't yet had time to separate those galaxies. Have any cosmologists succeeded in distinguishing these two possibilities?
 
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The fact that galaxies in the past were closer together isn't something we would have determined observationally, but something that follows from the expansion of the universe.
 
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I think I read a recent (and not definitive) article about observations from the James Webb Space Telescope, dealing somewhat with the issue (maybe in Nature or Nature Astronomy). I'll see if I can track it down.
 
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hkyriazi said:
I think I read a recent (and not definitive) article about observations from the James Webb Space Telescope, dealing somewhat with the issue (maybe in Nature or Nature Astronomy). I'll see if I can track it down.
If that is so, in effect, it could be just one more of the millions of fulfilled predictions of the Big Bang theory, as well as any other exotic thing that comes to mind.
 
  • #5
"I think I read somewhere" is hard to follow up on. I would hope that the article defines what "closer" means in an infinite universe where galaxies clump on multiple scales so we're all talking about the same thing.
 
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hkyriazi said:
Galaxies far away---that evolved soon after the Big Bang---are reported to be closer together than the galaxies we observe near us.
Reported where? As has already been commented, you need to give a specific reference. Otherwise we don't have a valid basis for discussion.
 
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1. What is the significance of the lack of mergers in ancient galaxies?

The lack of mergers in ancient galaxies is significant because it suggests that these galaxies have remained relatively undisturbed for billions of years. This means that they have not undergone major interactions or collisions with other galaxies, allowing them to retain their original structure and properties.

2. How does the lack of mergers affect our understanding of galaxy formation?

The lack of mergers challenges our current understanding of galaxy formation, as it was previously believed that mergers played a crucial role in the growth and evolution of galaxies. The absence of mergers in ancient galaxies suggests that there may be other mechanisms at play in the formation and evolution of these galaxies.

3. What evidence supports the idea of subsequent spatial expansion in ancient galaxies?

Observations of ancient galaxies have shown that they are more compact and have lower levels of star formation compared to their modern counterparts. This suggests that these galaxies have undergone a subsequent spatial expansion, where they have grown in size and become less dense over time.

4. How does the subsequent spatial expansion of ancient galaxies relate to the expansion of the universe?

The subsequent spatial expansion of ancient galaxies is believed to be a result of the overall expansion of the universe. As the universe expands, it stretches out the space between galaxies, causing them to grow in size and become less dense. This is consistent with the observed expansion of the universe.

5. What implications does this research have for our understanding of the universe?

The research on ancient galaxies and their lack of mergers and subsequent spatial expansion has significant implications for our understanding of the universe. It challenges our current theories of galaxy formation and evolution, and may lead to a better understanding of the mechanisms at play in the early universe. It also provides further evidence for the expansion of the universe and the role it plays in shaping the structure of galaxies.

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