Is there any gravitationally unbound' galactic clusters in observable universe

In summary, due to the expansion of space, even gravitationally connected objects can move away from each other faster than the speed of light. This is because the expansion of space causes the space between objects to increase, which can overcome the gravitational force between them. This is only possible for objects that are far enough apart and have a low enough gravitational force between them.
  • #1
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 ?
 
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  • #2


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.
 
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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
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
 
  • #4


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.
 
  • #5


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.
 

1. What is a gravitationally unbound galactic cluster?

A gravitationally unbound galactic cluster is a group of galaxies that are not held together by the force of gravity. This means that the galaxies are moving away from each other rather than being pulled towards each other.

2. How do scientists determine if a galactic cluster is gravitationally unbound?

Scientists use data from observations, such as the movement and distance of galaxies, to calculate the gravitational forces within a cluster. If the forces are not strong enough to keep the galaxies together, then the cluster is considered to be gravitationally unbound.

3. Are there any known gravitationally unbound galactic clusters in the observable universe?

Yes, there are several known gravitationally unbound galactic clusters in the observable universe. One example is the Draco Dwarf galaxy, which is believed to be moving away from the Milky Way due to the expansion of the universe.

4. What implications does the existence of gravitationally unbound galactic clusters have on our understanding of the universe?

The existence of gravitationally unbound galactic clusters challenges our understanding of the role of gravity in the universe. It also suggests that there may be other forces or factors at play in the movement and formation of galaxies.

5. Is there ongoing research or studies on gravitationally unbound galactic clusters?

Yes, scientists continue to study and research gravitationally unbound galactic clusters in order to better understand their properties and formation. This research can provide insights into the evolution of galaxies and the dynamics of the universe as a whole.

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