There is new theory one I mentioned before in the creation thread and that is the universe will end but its not going to retract in on its self I don’t believe. The theory goes like this. Do to the rapped expansion of the universe will get to the point where that its growth and rapped velocity will over come gravity, and sense everything is held together by gravity in one form or another that things will literally fall apart, being turned into dust. Now this universal decay will start on the larger scale which will be at the edge of the universe moving inward. But the thing is this. Even if it starts to it will still take billions of billions of billions of years before everything is torn a sunder which by then the Human race will be long gone. But we have nothing to fear as it is estimated that even with this new acceleration of the universe that it’s still only about half its life span right now. So the universe will still exist for several more billions of billions of billions of years before it starts to come undone.