B Is the formation of galaxy groups explained correctly here?

AI Thread Summary
The discussion centers on the formation of galaxy groups as explained in a Kurzgesagt video, which attributes their formation to gravity acting on denser regions of the universe after the Big Bang. Participants agree that while the video's explanation is largely correct, a simpler understanding could be that uneven matter distribution during inflation led to galaxy formation. Quantum fluctuations are highlighted as key contributors to this uneven distribution, resulting in varying densities that influenced gravitational collapse. The conversation emphasizes that these fluctuations create regions of higher and lower density, which ultimately shaped the structure of the universe. Overall, the explanation of galaxy group formation is validated, with quantum mechanics playing a significant role in the process.
PrincePhoenix
Gold Member
Messages
116
Reaction score
2
Hello!

I watched a video on the Youtube channel Kurzgesagt titled How far can we go? Limits of humanity
The video attempts to explain why we may be limited to our local galaxy group even with science fiction technologies.

During a part of the video (starting at 2:26), they try to explain how galaxy groups formed by saying that after the initial inflation period following big bang, gravity started to take hold. While it was too weak to get everything back together, in some pockets of space with more "denser" in terms of "energy" (quantum fluctuations before inflation) gravity was able to hold matter together and this formed groups/clusters of galaxies, within which matter is gravitationally linked. (If you think I might not phrasing it correctly and have time, I will appreciate it if you watch this section of the video directly)

Is this explanation correct? Wouldn't a simpler explanation be that matter was unevenly distributed during inflation and only those areas with high densities came together to form galaxy groups?
How do quantum fluctuations contribute to gravity? (My understanding of quantum fluctuations isn't much more than that explained in the video)

Thanks in advance. :)
 
  • Like
Likes 1oldman2
Astronomy news on Phys.org
PrincePhoenix said:
Is this explanation correct? Wouldn't a simpler explanation be that matter was unevenly distributed during inflation and only those areas with high densities came together to form galaxy groups?

The explanation is pretty much correct. As for "simpler", your explanation may be simpler, but it requires that someone already know a bit about how gravity works.

PrincePhoenix said:
How do quantum fluctuations contribute to gravity? (My understanding of quantum fluctuations isn't much more than that explained in the video)

Quantum fluctuations lead to slightly different densities in different regions of the very early universe. The regions that were more dense are the ones that collapsed to form galaxies. The regions that were less dense tended to become voids.
 
Drakkith said:
The explanation is pretty much correct. As for "simpler", your explanation may be simpler, but it requires that someone already know a bit about how gravity works.
Quantum fluctuations lead to slightly different densities in different regions of the very early universe. The regions that were more dense are the ones that collapsed to form galaxies. The regions that were less dense tended to become voids.

Thank you for the answer. :smile:

Can you please explain how quantum fluctuations affected the distribution of matter? (I assume you were referring to the distribution of mass in space with your use of the phrase "...different densities in different regions...")
 
  • Like
Likes 1oldman2
PrincePhoenix said:
Can you please explain how quantum fluctuations affected the distribution of matter? (I assume you were referring to the distribution of mass in space with your use of the phrase "...different densities in different regions...")

The quantum fluctuations are variations in the position of matter and radiation in space via quantum effects (uncertainty principle, etc). This naturally leads to areas with higher or lower than average densities.
 
  • Like
Likes PrincePhoenix and 1oldman2
Drakkith said:
The quantum fluctuations are variations in the position of matter and radiation in space via quantum effects (uncertainty principle, etc). This naturally leads to areas with higher or lower than average densities.

Thank you for the explanation.
 
This thread is dedicated to the beauty and awesomeness of our Universe. If you feel like it, please share video clips and photos (or nice animations) of space and objects in space in this thread. Your posts, clips and photos may by all means include scientific information; that does not make it less beautiful to me (n.b. the posts must of course comply with the PF guidelines, i.e. regarding science, only mainstream science is allowed, fringe/pseudoscience is not allowed). n.b. I start this...
Asteroid, Data - 1.2% risk of an impact on December 22, 2032. The estimated diameter is 55 m and an impact would likely release an energy of 8 megatons of TNT equivalent, although these numbers have a large uncertainty - it could also be 1 or 100 megatons. Currently the object has level 3 on the Torino scale, the second-highest ever (after Apophis) and only the third object to exceed level 1. Most likely it will miss, and if it hits then most likely it'll hit an ocean and be harmless, but...
Back
Top