The Crab Nebula

The Crab Nebula (M1), is the remnant of a stellar explosion that was seen by astronomers in the year 1054 AD.

The nebula's filaments are the tattered remains of the star and consist mostly of hydrogen. In the center of the nebula lies a neutron star, the crushed ultra-dense core of the exploded star. The rapidly spinning neutron star is the dynamo powering the nebula's eerie interior bluish glow. The blue light comes from electrons whirling at nearly the speed of light around magnetic field lines from the neutron star. The neutron star, like a lighthouse, ejects twin beams of radiation that appear to pulse 30 times a second due to the neutron star's rotation.

The Crab Nebula derived its name from its appearance in a drawing made by Irish astronomer Lord Rosse in 1844, using a 36-inch telescope. When viewed by the Hubble Space Telescope and large ground-based telescopes, the Crab Nebula takes on a more detailed appearance that yields clues into the spectacular demise of a star 6,500 light-years away.

This mosaic image was assembled from 24 individual Hubble exposures taken with the Wide Field and Planetary Camera 2 in October 1999, January 2000, and December 2000. The colors in the image indicate the different elements that were expelled during the explosion. Blue in the filaments in the outer part of the nebula represents neutral oxygen, green is singly ionized sulfur, and red indicates doubly ionized oxygen.

Credits: NASA, ESA, J. Hester and A. Loll (Arizona State University)