The joint data from several NASA satellites has amazed astronomers by revealing unexpected changes in X-ray discharge from the Crab Nebula, once thought to be the steadiest high-energy source in the sky. "For 40 years, most astronomers considered the Crab as a standard candle," said Colleen Wilson-Hodge, an astrophysicist at NASA's Marshall Space Flight Center in Huntsville, Ala., who offered the findings today at the American Astronomical Society meeting in Seattle.
The Crab Nebula is the wreckage of an exploded star whose light reached Earth in 1054. It is one of the most studied objects in the sky. At the heart of an expanding gas cloud lies what's left of the unique star's core, a superdense neutron star that spins 30 times a second.
All of the Crab's high-energy emissions are thought to be the result of physical processes that tap into this rapid spin. This sight of the Crab Nebula in visible light comes from the Hubble Space Telescope and spans 12 light-years. The supernova remnant, located 6,500 light-years away in the group Taurus, is among the best-studied objects in the sky.
All of the Crab's high-energy emissions are thought to be the result of physical processes that tap into this rapid spin. This sight of the Crab Nebula in visible light comes from the Hubble Space Telescope and spans 12 light-years. The supernova remnant, located 6,500 light-years away in the group Taurus, is among the best-studied objects in the sky.
0 comments:
Post a Comment