Death Watch
 The star Betelgeuse, shown in this Hubble Space Telescope image, is destined to end its life as a supernova -- an explosion so powerful that it will briefly shine as brightly as hundreds of millions of normal stars. Betelgeuse is a supergiant star, which is many times as massive as the Sun. Such stars will live less than one percent as long as the Sun. [NASA/STScI]
You might think that with modern telescopes, computers, and orbiting observatories, astronomers would know just when to look for such an event. But the action that creates the explosion takes place in the star's core, hundreds of millions of miles below its surface. So far, astronomers haven't discovered any activity on a star's surface to tell them when an explosion is imminent - although that may change in the coming years.
Betelgeuse is one of the heaviest stars in the galaxy. As a result, its core is extremely hot, allowing it to quickly "fuse" the heavier elements it creates. As it consumes each new element, gravity squeezes the core tighter, making it hotter - and allowing it to fuse the next element.
Eventually, the core will be converted to iron. The iron can't fuse together to make heavier elements, so the core will collapse to form a neutron star - and the star will explode as a supernova. More about that tomorrow.
You can keep an eye on Betelgeuse, too. The star is low in the east about 90 minutes before sunrise. It's a star that may explode in 10,000 years - or as soon as tonight.
Script by Damond Benningfield, Copyright 2005
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