Expansion-Collapse cycle in cosmological structures?

In summary, cosmological structures such as galaxies, clusters of galaxies, and gas bodies can be attracted to each other by gravity if they are close enough, but can also be pushed further apart by the expansion of the universe if they are far enough apart. In some cases, these structures can detach from the expansion and start being pulled towards each other by gravity. There is a possibility that these structures may follow a cycle of expansion and contraction, but it has not been observed yet.
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Suekdccia
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TL;DR Summary
Expansion-Collapse cycle in cosmological structures: Is it possible?
Concerning cosmological structures (like galaxies, clusters of galaxies, gas bodies, superclusters...etc) if the elements that make them are close enough they will be attracted towards each other by gravity. Contrarily, if they are sufficiently far apart they will get further away following the expansion of the universe.

However, sometimes, even if objects follow the expansion of the universe, under some conditions, they can "de-attach" from it and start being attracted to each other by gravity.

Is it possible that these cosmological structures may follow a cycle between expansion and contraction? I mean, is it possible that a structure expands with the Hubble flow, then it stops and starts shrinking, and then, somehow, after collapsing, starts following the Hubble flow repeating this cycle indefinitely? Has this been ever observed?
 
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Suekdccia said:
sometimes, even if objects follow the expansion of the universe, under some conditions, they can "de-attach" from it and start being attracted to each other by gravity.
Do you have a reference for this?
 

1. What is the Expansion-Collapse cycle in cosmological structures?

The Expansion-Collapse cycle is a phenomenon that occurs in the universe where matter is constantly expanding and contracting in a cyclical pattern. It is a key concept in cosmology and is believed to be responsible for the formation of galaxies, stars, and other structures in the universe.

2. How does the Expansion-Collapse cycle affect the universe?

The Expansion-Collapse cycle plays a crucial role in shaping the universe. It is responsible for the formation of large-scale structures such as galaxies, clusters of galaxies, and superclusters. It also affects the distribution of matter and energy in the universe, leading to the formation of stars and planets.

3. What causes the Expansion-Collapse cycle?

The Expansion-Collapse cycle is caused by the force of gravity. As matter in the universe attracts each other, it pulls together and forms structures. Over time, these structures become more massive and eventually collapse under their own gravity. However, the expansion of the universe counteracts this collapse, leading to a cyclical pattern.

4. Can we observe the Expansion-Collapse cycle?

Yes, we can observe the Expansion-Collapse cycle through various astronomical observations. For example, the redshift of light from distant galaxies indicates that the universe is expanding, while the structure of the cosmic microwave background radiation reveals the imprints of past collapse events. Additionally, computer simulations based on our understanding of cosmological models can also help us visualize the Expansion-Collapse cycle.

5. Is the Expansion-Collapse cycle infinite?

The Expansion-Collapse cycle is currently believed to be infinite. It is a fundamental process that has been occurring since the beginning of the universe and is expected to continue for an indefinite amount of time. However, the rate of expansion and collapse may change in the future, leading to different outcomes for the universe.

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