if the big crunch theory is true, how long until the universe ends?

Answer 1

Unknown. It depends how close to the critical density the universe is, the nature of dark matter and dark energy, the shape of the universe, and if the theory is correct.

Answer 2

The big crunch theory isn't so strong anymore, because of the recent mapping of the cosmic microwave background by COBE (Nobel Prize last year). Even so, you can't predict a time frame because of how many factors are involved. The only universe death theory that is certain is the Heat Death of the universe, that all physicists agree is the ultimate end of all, but there is no time frame for that one either except that it is really far away.

The heat death theory goes like this. In every process in the universe, entropy either increases or stays the same. Entropy is a measure of disorder. Usable energy is converted to unusable energy. Eventually, nothing has any capacity to do anything, and the entire universe is at the same temperature, and all is dead and motionless.

Answer 3

There is no way to solve this problem— we don't know enough yet. We don't even have a satisfactory answer as to why its expansion is still accelerating. Based on our current understanding of physics, the expansion should be slowing down under the influence of gravity.

My personal feeling is that we will discover some fundamental property of spacetime that explains the acceleration of expansion and predicts continued expansion, until spacetime becomes completely flat. This will in turn give rise to a quantum instability that causes another "big bang," only in the universe that arises, what we consider to be our entire universe will have been its "primordial singularity," smaller than the smallest quark (or whatever structure of matter arises in this new universe). The cycle will repeat indefinitely. Similarly, I think a whole progression of universes we would percieve as infinitely tiny have preceded this one.

Answer 4

The preponderance of evidence is that the universe will continue to expand forever, with its expansion rate even accelerating. So, for it to crunch, something not understood about gravity would have to be at work. This is possible; the accelerated expansion rate already shows that we don't understand everything about it. However, since we don't know what would cause the universe to re-collapse, when that would occur is anyone's guess. 10's or even 100's of billions of years would be the range of time one might expect this to take.

Answer 5

O_O i must look up this theory at once!

Answer 6

When the captain says its over.

Answer 7

The New Testament explains that no man knows when the end will be.

Answer 8

Qdot = (keff)(Fg)(cm^3)(J/s)(1/3.432) = 3275.344326 years.