Ancient galaxies: lack of mergers vs. subsequent spatial expansion

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Discussion Overview

The discussion centers on the spatial distribution of ancient galaxies, specifically addressing why galaxies that evolved shortly after the Big Bang appear to be closer together than those observed in the present day. Participants explore two main hypotheses: the potential for mergers among nearby galaxies over time and the effects of spatial expansion from the Big Bang. The conversation touches on observational evidence and theoretical implications.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants suggest that the observed proximity of ancient galaxies could be due to mergers of nearby galaxies over time, while others propose that spatial expansion from the Big Bang may not have had sufficient time to separate these galaxies.
  • One participant notes that the conclusion about ancient galaxies being closer together is not based on direct observation but rather follows from the theoretical framework of the universe's expansion.
  • Another participant mentions a recent article related to the James Webb Space Telescope that may provide insights into this issue, although they caution that the findings are not definitive.
  • Concerns are raised about the clarity of terms like "closer" in the context of an infinite universe, highlighting the need for precise definitions in the discussion.
  • A participant questions the validity of the claims made without specific references to observational data, emphasizing the importance of grounding discussions in verifiable sources.

Areas of Agreement / Disagreement

Participants express differing views on the interpretation of the proximity of ancient galaxies and the implications of spatial expansion versus mergers. The discussion remains unresolved, with no consensus reached on the primary cause of the observed phenomena.

Contextual Notes

Participants note limitations in the discussion, such as the need for specific references to observational data and the ambiguity of terms used in describing galaxy proximity in an infinite universe.

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TL;DR
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.
 
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.
 
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.
 
"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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