he critical density is given by the Greek letter omega. If omega is less than one the Universe will continue expanding until it is so large that it dies a cold death. If omega equals one the Universe will eventually stop expanding but will not collapse. In this case the Universe will also die a cold static death. But, if omega is greater than one, then the Universe is doomed to collapse under it's own gravitational mass, and will die a hot, fiery death in a big crunch. But don't worry, the ultimate fate of the Universe is atleast ten billion years away....
