Crab Nebula
 The remnants of an exploded star spread across the sky in this recent view from Hubble Space Telescope. The streamers of gas and dust form the Crab Nebula, which spans about six light-years. It formed when a massive star exploded as a supernova, blasting most of its material into space and leaving only its crushed core -- a superdense neutron star. The green filaments are rich in sulfur, while red and blue contain concentrations of oxygen. [Credit: NASA/ESA/J. Hester/A. Loll (Arizona State)]
The Crab was born when a star about 10 times as massive as the Sun exploded as a supernova. Skywatchers observed the blast in the year 1054. The star's outer layers were blasted into space. This material now spans about 10 light-years, and it continues to expand.
The star's core survived the blast, but in a very different form. It was crushed so tightly that it formed a neutron star -- a ball that's perhaps twice as massive as the Sun, but only about as big as Austin. This ball spins about 30 times a second. As it spins, it interacts with its powerful magnetic field to send out "jets" of charged particles.
The magnetic field and the nebula's odd shape may reveal something about the explosion that created the Crab -- and we'll talk about that tomorrow.
Look for the Crab Nebula in the constellation Taurus, the bull, which is well up in the east this evening. A V-shaped pattern of stars forms his face. The Crab is near the tip of the bull's left horn. Binoculars reveal a fuzzy patch of light. But you need a good telescope to see any of the Crab's wispy structure.
Script by Damond Benningfield, Copyright 2005
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