Is there any gravitationally unbound' galactic clusters in observable universe

  • Thread starter hitchiker
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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 ?
 

HallsofIvy

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Re: is there any "gravitationally unbound' galactic clusters in observable universe

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.
 
Re: is there any "gravitationally unbound' galactic clusters in observable universe

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
 
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Re: is there any "gravitationally unbound' galactic clusters in observable universe

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.
 

Drakkith

Staff Emeritus
Science Advisor
2018 Award
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Re: is there any "gravitationally unbound' galactic clusters in observable universe

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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