Will the Universe end?

It is difficult to think that the Universe might end some day. But cosmologists, the people who study the Universe, are sure it will. They think it will stop expanding outwards, and start shrinking back to nothing. They call this event the 'Big Crunch'. The stars will burn out gradually, and finally, there will be just lumps of rock and dust floating around. However, don't worry too much about it. All this is billions, and possibly trillions of years from now. Moreover, there are still some scientists who think that this won't happen at all, and that the Universe will go on forever. They figure that gravity won't allow the Universe to stop expanding, and so it will just keep getting bigger and bigger!