How Small Could the Universe Get in a Big Crunch?

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In summary, the size of a Big Crunch is determined by the amount of matter and energy in the universe, as well as the rate of expansion. It is significantly smaller than the current size of the universe and is estimated to be incredibly small, potentially even smaller than a single atom. Its size is similar to that of a black hole, both involving a singularity with infinite density, but a Big Crunch involves the entire universe while a black hole is localized. The size of a Big Crunch is constantly changing as the universe contracts until it reaches a singularity with infinite density.
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Olias
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Interesting dynamical overview of 3-D >>2-D Ttransitions.

http://arxiv.org/PS_cache/hep-th/pdf/0408/0408220.pdf
 
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I could ask Russo, given that he lives in my city, but I will save the phone call and will ask here: I'm a bit familiar with the Milne universe, actually not mainstream because cosmologists prefere general relativity, but never heard of this thing that he calls the Milne horizon. What's this?
 
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The concept of a "big crunch" refers to a hypothetical scenario in which the universe, which is currently expanding, eventually stops expanding and begins to contract back towards a central point. This contraction would continue until all matter and energy in the universe is compressed into a single point, resulting in a "big crunch."

The size of a big crunch is difficult to determine because it depends on various factors, such as the amount of matter and energy in the universe and the rate of expansion. However, according to current theories, the size of a big crunch would be incredibly small, perhaps even smaller than an atom.

In the paper provided, the author discusses the interesting dynamics of a 3-dimensional universe transitioning to a 2-dimensional universe. This type of transition is known as a "dimensional reduction" and is a topic of interest in theoretical physics.

The author suggests that this transition may occur as the universe approaches a big crunch, where the extra dimensions of space become compactified and the universe becomes effectively 2-dimensional. This is an intriguing concept, as it challenges our understanding of the fundamental nature of space and time.

Overall, the idea of a big crunch and the potential for a dimensional reduction provides a fascinating perspective on the evolution of the universe. While the exact size of a big crunch may be difficult to determine, the concept itself raises thought-provoking questions about the nature of our universe.
 

FAQ: How Small Could the Universe Get in a Big Crunch?

How is the size of a Big Crunch determined?

The size of a Big Crunch is determined by the amount of matter and energy in the universe, as well as the rate of expansion. As the universe contracts, the distance between objects decreases, making the universe smaller.

How small is a Big Crunch compared to the current size of the universe?

A Big Crunch is significantly smaller than the current size of the universe. During a Big Crunch, the entire universe is compressed into a single point, known as a singularity.

What is the estimated size of a Big Crunch?

The estimated size of a Big Crunch is incredibly small, potentially even smaller than a single atom. This is because the universe would be compressed into a singularity, which is thought to have infinite density.

How does the size of a Big Crunch compare to the size of a black hole?

The size of a Big Crunch and a black hole are similar in that they both involve a singularity with infinite density. However, a Big Crunch would involve the entire universe, while a black hole is a localized phenomenon with a specific size based on its mass.

Is the size of a Big Crunch constant or does it change?

The size of a Big Crunch is constantly changing as the universe contracts. As the distance between objects decreases, the size of the universe also decreases until it reaches the singularity. At this point, the size becomes infinitely small.

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