dipper@utastro.UUCP (Debbie Byrd) (10/09/85)
A supernova is an exploding star. In a minute, we'll tell you about a supernova no one saw. More after this. October 9: The Supernova No One Saw In the constellation Cassiopeia, an intriguing feature exists at the limits of visibility. You can't see this feature, which we call Cas A, with the unaided eye. But photographs show turbulent filaments of gas that hurtle outward from a common center. It's thought these filaments are matter ejected from a supernova -- a dying star that exploded. When a supernova erupts, it causes a star to increase in brightness a billion times over. Cas A has puzzled astronomers -- because many astronomers were watching the skies when it supposedly erupted three hundred years ago. And yet -- no one saw the supernova. Why not? Well, maybe interstellar dust came between us and it. Or maybe the supernova was abnormally quiet, with low intrinsic luminosity. A more modern -- and more far-out idea is that a black hole formed in the supernova, which swallowed the light of the explosion. Still other astronomers believe the object WAS seen by at last one 17th century skywatcher, who may have recorded the supernova in a catalogue as an ordinary star. In any case, although the eruption passed unnoticed at the time, the remnant left behind by the spernova is very conspicuous today. Cas A is the strongest source of radio energy in the sky. Although it's likely most of you will never SEE Cas A, it's possible all of you have HEARD it -- as static on your radio dials. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin