astronomy: supernova puts on stellar light show

NASA’s Hubble Space Telescope has recorded yet another dramatic image of the universe around us, this time the death throes of a fading supernova. Called SN 1987A, the brightest stellar explosion of modern times was discovered by astronomers 17 years ago. Today the supernova is a million times fainter, but this image captured by Hubble on November 28, 2003 shows it is going out with style. A star goes supernova when it exhausts its fuel supply. Its core collapses, sending out a shock wave that tears the star apart. Now SN 1987A’s shock wave is slamming at a speed of more than a million miles per hour into a ring of gas that the star shed some 20,000 years before the explosion, heating it up and making it glow, producing the “pearls” of light seen here. The pearls will eventually turn into a solid glowing ring as the full force of the wave is absorbed in the next few years. Astronomers hope that the ring will be bright enough to light up the star’s surroundings, giving them more data on how the star ejected material before the blast.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 2/24/2004.