Is there any gravitationally unbound' galactic clusters in observable universe

AI Thread Summary
The discussion centers on the concept of gravitationally unbound galactic clusters and their relationship to the expansion of the universe. Participants debate whether all matter is gravitationally interconnected, questioning how distant galaxies can appear to move faster than light due to space expansion if they are gravitationally bound. It is noted that coherent structures, like solar systems, are not affected by this expansion, suggesting a critical threshold of gravitational influence. The conversation highlights the tension between gravitational forces and the metric expansion of space, with some asserting that expansion can overpower gravity under certain conditions. Ultimately, the complexities of General Relativity and the nature of cosmic expansion remain central to understanding these phenomena.
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is there any "gravitationally unbound' galactic clusters in observable universe

images?q=tbn:ANd9GcSptnWVYk1JSiHBxW6Ccqcr5lhqUai0XNtXNzVvqHfTcDvkvEtM.jpg

my hunch is that everything in the universe is gravitationally tugged on each other ..we can say moon is connected to andromeda galaxy in a way [process]moon->earth->sun->milkyway->andromeda[/process] even the slightest imbalance in mass would cause one to slide on to other slowly overtime...so when Hubble data says farther galaxies are moving away from us due to metric expansion of space(only between gravitationally unbound) does it mean they are gravitationally free standing structures surrounded by billions of lightyear wide flat spacetime ?how could there be flat space time over large scale if matter is homogeniously distributed in universe ?
 
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Every object in the universe is affected, at least to some tiny amount, by every other object. That is true in both classical Newtonian gravity and relativity. Expansion of space has nothing to do with that.
 


Every object in the universe is affected, at least to some tiny amount, by every other object. That is true in both classical Newtonian gravity and relativity. Expansion of space has nothing to do with that
my understanding from usual reading is that solar system will not be affected by expansion of space because it's gravitationally coherent

BIG BANG THEORY
The universe expands, but coherent objects inside it do not.

so if all matter is connected by gravity. how do distant galaxies are hypothesized to move faster than light because of expansion of space NOTE what BBT says above, if they are gravitationally connected expansion of space shouldn't be effective on them ,
does expansion of space overpower gravity, if gravity between 2 bodies are below certain critical value
 


hitchiker said:
my understanding from usual reading is that solar system will not be affected by expansion of space because it's gravitationally coherent

BIG BANG THEORY
The universe expands, but coherent objects inside it do not.

so if all matter is connected by gravity. how do distant galaxies are hypothesized to move faster than light because of expansion of space NOTE what BBT says above, if they are gravitationally connected expansion of space shouldn't be effective on them ,
does expansion of space overpower gravity, if gravity between 2 bodies are below certain critical value

See here.
 


hitchiker said:
does expansion of space overpower gravity, if gravity between 2 bodies are below certain critical value

Without getting into an in depth discussion of the math underlying General Relativity and the expansion of space, yes.
 
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