How will the universe all end?

Generally, there are two main theories to the end.

Heat Death/Big Freeze and the Big Crunch.

Heat Death/Big Freeze is (taken from Wikipedia):

"The Big Freeze is a scenario under which continued expansion results in a universe that is too cold to sustain life. It could, in the absence of dark energy, occur only under a flat or hyperbolic geometry. With a positive cosmological constant, it could also occur in a closed universe. A related scenario is Heat Death, which states that the universe goes to a state of maximum entropy in which everything is evenly distributed, and there are no gradients — which are needed to sustain information processing, one form of which is life. The Heat Death scenario is compatible with any of the three spatial models, but requires that the universe reach an eventual temperature minimum."

Big Crunch is (taken from Wikipedia):

"The Big Crunch theory is a symmetric view of the ultimate fate of the universe. Just as the Big Bang started a cosmological expansion, this theory postulates that the average density of the universe is enough to stop its expansion and begin contracting. The end result is unknown; a simple extrapolation would have all the matter and space-time in the universe collapse into a dimensionless singularity, but at these scales unknown quantum effects need to be considered (See Quantum gravity).

This scenario allows the Big Bang to have been immediately preceded by the Big Crunch of a preceding universe. If this occurs repeatedly, we have an oscillatory universe. The universe could then consist of an infinite sequence of finite universes, each finite universe ending with a Big Crunch that is also the Big Bang of the next universe. Theoretically, the oscillating universe could not be reconciled with the second law of thermodynamics: entropy would build up from oscillation to oscillation and cause heat death. Other measurements suggested the universe is not closed. These arguments caused cosmologists to abandon the oscillating universe model. A somewhat similar idea is embraced by the cyclic model, but this idea evades heat death, because of an expansion of the branes that dilutes entropy accumulated in the previous cycle."

There are many more theories. If you want to see the rest, go here:

http://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe

The shape of the universe is also key to the ultimate fate.

If the universe is closed (think of it like a sphere and we are inside it), then both theories are possible. If the universe is open, then the Big Crunch is not possible. Recent evidence has shown that the universe's expansion rate is increasing, making the theory of an open universe highly likely.

For me, I think that the Big Bang had to be caused by something. The only thing that I can think that could cause the Big Bang, is a Big Crunch.

fuck knows, well all be long dead anyway

It won't end, probably ever. The universe is actually expanding faster now than it ever has been before. This may or may not be because of "dark energy."

Most astronomers theorize that the universe is either relatively flat or a hyperbola which would never collapse in on itself. It would be different if it were more of a spherical shape, then we would have a risk of universal collapse.

Everything will explode cause we're all inside an atom!!!!!!!!!

I believe in the Second Law of Thermodynamics (It's impossible to decrease the total entropy of the universe, and the entropy is always increasing). That'll lead to the stars extinguishing, which will lead to heat death. What's after that, I don't know

whatever happens happens, iv always found it silly that some people spend their lives researching something that humanity shouldent concern itself with, by the time it happens we will be extinct so why waste time debating and researchig this

 It's fun... Talking about doom and gloom and causing fear aswell...

What do you guys think created the universe? I'm aware that the current universe started from the Big Bang, but what triggered it? What us the origin of matter and energy? The cycle must have had some start, rather than being ever-present.

Everyone talking about expanding and doom and gloom. But, how come, nobody stopped to think, what exactly is the universe expanding out to? Where are all these empty spaces coming from?
What happened if you expand outside it? Would that be the place where "god" lives?
Would we all turn into "gods" if you expanded there?

When can we severe ourselves of the Sun and journey for "goddome"?

Yes, I've actually thought about it sometimes. The universe is indeed expanding, but for it to expand, there must be an empty space. And just what is this empty space? The end? Or the dividing line between this universe and something else?

I don't understand any of this. I wish I would though. That's why I'm going to research into this when I'm older.

I always thought the Big Crunch theory made the most sense.