Supernova Explosions: The Spectacular Death of Massive Stars

When Stars Attack!

• Supernova explosions: the death of massive stars
• Cosmic WMD: supernova explosions near Earth
• How would we know? supernova debris found as live radioactivity in the deep ocean
• Implications and future directions
• Movies and Talks
• Links to more information

A supernova explosion: SN 1987A in the Large Magellanic Cloud

The most massive stars end their lives in some of the most spectacular and violent events in the Universe. A star with mass more than about 8 times that of the Sun lives a relatively brief life as it struggles to maintain stability against its own gravity. This struggle ends in surrender, as the star finally collapses under its own weight. The result is an immensely powerful explosion--a supernova--whose brilliance can briefly outshine an entire galaxy's worth of normal stars. In the aftermath, a compact central object remains, in the form of neutron star or black hole. However, most of the star's material is launched through space in a shock wave. This matter contains the ashes of the star's nuclear burning, in the form of newly created heavy elements. The blast wave carries this material, and as it advances it sweeps up and mixes with the nearby interstellar gas.

Supernova explosions play a crucial role in the "ecology" of our Galaxy: they act as engines to cycle energy and heavy elements into interstellar space, and the blast waves created by their explosions shock and stir interstellar gas, and may compress some interstellar gas clouds to the point driving them to collapse and form new stars.

Rapidly expanding, superheated remains of a supernova blast 300 years ago, seen with the X-ray vision of the Chandra observatory.