More Crab Nebula
Almost a millennium ago as seen from Earth, a massive star blew itself to bits. Today, its fractured remains form one of the most important objects in the night sky: the Crab Nebula. It's a vital laboratory for studying how stars explode, how they blast chemical elements into space, and what happens to their leftover cores.
The explosion itself was so bright that for weeks it shined as the brightest object in the night sky other than the Moon -- even though it was about 6500 light-years away.
The star exploded when its core stopped producing energy and collapsed, forming a neutron star -- an object that's more massive than the Sun, but smaller than a city. A shock wave and other processes blew the star's outer layers into space. The energy of the blast created heavy elements, which are racing into the galaxy at more than a thousand miles a second. Someday, these elements may be incorporated into new stars and planets.
The neutron star spins about 30 times a second. It beams out "pulses" of energy, like a lighthouse, so it's also known as a pulsar. But it's slowing down faster than most other pulsars. Astronomers thought that might mean it's not perfectly round. If that were the case, it would produce ripples in space and time known as "gravitational waves." But so far, scientists have detected no gravitational waves from the pulsar. So other processes must be slowing it down -- a millennium after its birth.
Script by Damond Benningfield, Copyright 2008
For more skywatching tips, astronomy news, and much more, read StarDate magazine.