dipper@utastro.UUCP (Debbie Byrd) (01/19/85)
Ever wonder what might be outside the universe? We talk about it -- right after this. January 19: Expanding Space A listener in Colorado asked a question about cosmology, which is the science of the universe as a whole. He wrote, "If you subscribe to the Big Bang Theory, then it stands to reason that the universe is expanding. If this is the case, then what is the universe expanding into?" Well, it's true that the universe is expanding. We can see that through great telescopes -- the galaxies that contain the stars all are moving away from one another. It's thought that this expansion started more than l0 billion years ago, in a colossal primordial explosion that we call the Big Bang. The Big Bang marked the initial liberation of all the matter and energy in the universe. But if matter as we know it didn't exist before the Big Bang -- well then neither did space. The universe, by definition, is everything that exists. Space and matter -- and also time -- all were born in the Big Bang. So what's the universe expanding into? If the universe is all that we know to exist, then what can exist outside of it? Although astronomers can answer this question mathematically, it's hard to picture the answer in words. We can't imagine what lies outside our ordinary three dimensions of space -- anymore than a creature who lived on a totally flat surface, in two dimensions only, could picture moving up or down into a third dimension. But theories indicate that other dimensions can exist -- proving that there are no boundaries on the universe of the imagination. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin