The Universe is expanding right now, which is easily proveable. Don't listen to 2, he doesn't know WTF he's talking about, and 3 is a retard/troll (same thing). I think you really mean whether the Universe will eventually end in a Big Crunch/Big Bounce (Universe eventually reverses it's expansion and collapses into a sort of reverse Big Bang, possibly then rebounding into a new Universe) or a Big Freeze/Heat Death (Universe continues to expand until the only things left in the entire Universe are photons that are below the visible spectrum). Of course, there are many other hypotheses, but most of them involve certain unscientific bullshit *cough*strings*cough*.