Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2002 September 20
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

The Crab Nebula Pulsar Shrugs
Credit: J. Hester (ASU), CXC, HST, NRAO, NSF, NASA

Explanation: How does a city-sized neutron star power the vast Crab Nebula? The expulsion of wisps of hot gas at high speeds appears to be at least part of the answer. Yesterday time-lapse movies taken from both the Chandra X-ray Observatory and the Hubble Space Telescope were released showing a wisp of gas moving out at about half the speed of light. Wisps like this likely result from tremendous electric voltages created by the central pulsar, a rapidly rotating, magnetized, central neutron star. The hot plasma strikes existing gas, causing it glow in colours across the electromagnetic spectrum. Pictured above is a composite image of the centre of the Crab Nebula where red represents radio emission, green represents visible emission, and blue represents X-ray emission. The dot at the very centre is the hot pulsar spinning 30 times per second.

Tomorrow's picture: Moonset

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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