Can a closed universe expand forever?

Thread starter Crazy4Physics
Start date Nov 10, 2013
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Closed Universe

In summary, a closed universe is a model in which space is curved and eventually leads to a "Big Crunch." Scientists determine the shape of the universe by studying the cosmic microwave background radiation and other data. However, recent observations suggest that the universe may continue to expand and not collapse. There are also other theories such as the "Big Rip" and "Heat Death" about the fate of a closed universe, but they require further research.

Nov 10, 2013

Crazy4Physics

Most say that a closed universe would collapse. Recent observations show that the universe will probably keep on expanding forever. Does this mean we cannot live in a closed universe? Or, is there a loop hole which allows a closed universe to expand forever?

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Nov 10, 2013

mathman

Science Advisor

It depends on the geometry of the universe. 2-d analog: blow up a balloon and the surface can expand forever (unless it breaks).

1. Can a closed universe expand forever?

It is currently believed that a closed universe cannot expand forever. According to the Big Bang theory, the expansion of the universe is driven by the energy of the initial explosion. However, the strength of this energy is not enough to counteract the gravitational pull of all matter in the universe. As a result, the expansion of the universe will eventually slow down and come to a stop, followed by a contraction phase.

2. What is a closed universe?

A closed universe is a model of the universe in which space is curved in such a way that if you were to travel in one direction, you would eventually return to your starting point. This type of universe is often compared to a finite sphere, where the surface is finite but has no edges. A closed universe can also be referred to as a "spherical universe."

3. How do scientists determine the shape of the universe?

Scientists determine the shape of the universe by studying the cosmic microwave background radiation (CMB) left over from the Big Bang. The pattern of the CMB can reveal information about the curvature of space, which can help determine the overall shape of the universe. Additionally, scientists also use data from galaxy surveys and measurements of the expansion of the universe to further understand its shape.

4. Can a closed universe eventually lead to a "Big Crunch"?

Yes, a closed universe can eventually lead to a "Big Crunch," which is a hypothetical scenario where the universe collapses in on itself due to the force of gravity. This is the opposite of the Big Bang, where the universe was thought to have expanded from a single point. However, recent observations suggest that the expansion of the universe is accelerating, making a "Big Crunch" less likely.

5. Are there other theories about the fate of a closed universe?

Yes, there are other theories about the fate of a closed universe. One theory is the "Big Rip," where the expansion of the universe accelerates to the point where all matter is torn apart. Another theory is the "Heat Death," where the universe continues to expand and cool until all energy is evenly dispersed, resulting in a state of maximum entropy and no possibility for life or thermodynamic processes. However, these theories are still speculative and require further research and evidence.