dipper@utastro.UUCP (Debbie Byrd) (09/15/85)
No one knows the fate of the universe. But cosmologists have some ideas -- which we'll tell you about -- after this. September 15 The Ultimate Destiny If the universe began in a Big Bang, where will it end? That's a question in cosmology, which is the science of the universe as a whole. According to cosmologists, the universe began about 15 billion years ago, in a cataclysmic explosion that we call the Big Bang. The Big Bang released the tremendous energy of the universe -- and sent it on its way to becoming galaxies and stars and planets -- and people like ourselves. Today, when we look through telescopes, we still see the galaxies rushing away from each other. These colossal structures each contain billions of stars -- and each galaxy more or less maintains its individual shape and size. But every galaxy is moving away from every other galaxy. That's what's meant by the expression "the expanding universe." It's possible that someday the galaxies might slow down. They might halt their outward rush and begin falling back toward each other -- like a movie of the expanding universe run in reverse -- a entire universe in collapse. Such a collapse might result in an oscillating universe -- which could explode again in another Big Bang -- collapse again -- and explode again -- infinitely. We don't know whether that will happen -- whether the universe will expand forever or someday collapse on itself. The answer depends on how much matter the universe contains. Enough matter -- and the self-gravity of the universe will someday make it collapse. Not enough matter -- and the universe will expand forever. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin