dipper@utastro.UUCP (Debbie Byrd) (09/16/85)
The galaxies may have arisen from cold, dark matter in the early universe. More -- after this. September 16 Cold, Dark Matter Yesterday we talked about the Big Bang -- the cataclysmic explosion that marked the birth of our universe. The idea of the Big Bang has been discussed and explored for about two decades -- but only in a general way -- since it has been hard to gather observational evidence about the birth of the universe. But since light travels at a finite speed, our telescopes are like time machines that let us look into the distant past. And advancing technology is letting astronomers look farther away in space -- and farther back in time -- closer to the birth of the universe. Now the specifics of the Big Bang theory can begin to be speculated on -- and more detailed theories about the very early universe are being devised. A recent popular theory explores the reason that matter in the universe came together to form galaxies -- huge islands of stars that are the major structures in the universe. Cosmologists propose that the early universe was filled with what they call "cold, dark matter" -- stuff unlike the ordinary matter around us here on Earth, or in the solar system. The cold, dark matter spread outward unevenly from the Big Bang -- and formed "gravitational potholes" into which ordinary matter fell and became trapped. In this picture of the early universe, that's how galaxies began to form. Today it's possible that what's left of the cold, dark matter still exists. It may account for the so-called missing mass -- the idea that a large fraction of the mass of the universe appears to be completely invisible. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin