SOHO spacecraft finds 1,500th comet

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The SOHO spacecraft discovered its 1,500th comet this week, making the observatory the most successful comet detector.

The NASA/ESA Solar and Heliospheric Observatory made its historic discovery on June 25, thanks to U.S.-based amateur astronomer Rob Matson. That puts SOHO's count ahead of all other discoverers of comets throughout history combined.

SOHO launched in 1995 to study solar physics and space weather, but its prime location between the sun and the Earth gives an excellent view of the space inside Earth's orbit. The spacecraft records comets as they slowly lose ice and often disintegrate in orbit around the sun.

"This is allowing us to see how comets die," said Karl Battams, SOHO researcher at the Naval Research Laboratory in Washington, D.C.

Volunteers and astronomers can pore over downloaded data from SOHO to try and find comets. Findings get checked by Battams and then passed on to the Minor Planet Center, where the comets get cataloged and have their orbits calculated.

Roughly 85 percent of SOHO's comet discoveries involve a collective of icy objects known as the Kreutz group — fragments of a giant comet that disintegrated while orbiting the sun centuries ago. The comet's offspring now pass within 932,000 miles (1.5 million km) of the sun, then are flung far out into the solar system on highly elliptical orbits.