According to modern cosmology, the Universe began about 10 or 15 billion years ago in an event known as the Big Bang. It has been expanding ever since. What we do not know is whether it will go on expanding forever. If the density of matter in the Universe is sufficiently large, gravitational forces will eventually cause the Universe to stop expanding, and then to start falling back in upon itself. If that happens, the Universe will end in a second cataclysmic event that cosmologists call The Big Crunch.
The Big Crunch
Author :
David Goodstein
