On Sunday, September 13, the NASA/ESA Solar and Heliospheric Observatory (SOHO) discovered its 3,000th comet.
The dot in the cross-hairs is a comet streaming toward the Sun, as seen on September 14, 2015, by SOHO. This is the 3,000th comet discovered in the data from the space observatory since it launched in 1995, Image credit: NASA / ESA / SOHO.
The comet was originally spotted by Thai writer and amateur astronomer Worachate Boonplod.
“I am very happy to be part of a great milestone for SOHO’s comet project. I would like to thank SOHO, ESA and NASA for making this opportunity possible, including other fellow comet hunters who I have learned a lot from,” Boonplod said.
Since launching almost twenty years ago, SOHO has become the number one comet finder of all time.
Prior to its launch, only a dozen or so comets had ever even been discovered from space, and some 900 had been discovered from the ground since 1761.
The spacecraft was built in Europe by an industry team led by Matra, and instruments were provided by European and American scientists. NASA was responsible for the launch and is now responsible for mission operations.
SOHO’s mission is to observe the Sun and interplanetary space, above Earth’s atmosphere that blocks so much of the Sun’s radiation.
From there, the spacecraft watches the solar disk itself and its surrounding environment, tracking the constant outward flow of particles known as the solar wind, as well as giant explosions of escaping gas called coronal mass ejections.
The observatory’s comet prowess, however, was unplanned and has turned out to be an unexpected benefit.
“SOHO has a view of about 12-and-a-half million miles beyond the Sun,” said SOHO mission scientist Dr Joe Gurman of NASA’s Goddard Space Flight Center.
“So we expected it might from time to time see a bright comet near the Sun. But nobody dreamed we’d approach 200 a year.”
