"Dirty Snowball" came close last night

"We won't be able to send a space probe to Comet Lulin, but Swift is giving us some of the information we would get from just such a mission," said Jenny Carter, at the University of Leicester, U.K., who is leading the study.

"The comet is releasing a great amount of gas, which makes it an ideal target for X-ray observations," said Andrew Read, also at Leicester.

A comet is a clump of frozen gases mixed with dust. These "dirty snowballs" cast off gas and dust whenever they venture near the sun. Comet Lulin, which is formally known as C/2007 N3, was discovered last year by astronomers at Taiwan's Lulin Observatory. The comet is now faintly visible from a dark site. Lulin will pass closest to Earth -- 38 million miles, or about 160 times farther than the moon -- late on the evening of Feb. 23 for North America.

On Jan. 28, Swift trained its Ultraviolet/Optical Telescope (UVOT) and X-Ray Telescope (XRT) on Comet Lulin. "The comet is quite active," said team member Dennis Bodewits, a NASA Postdoctoral Fellow at the Goddard Space Flight Center in Greenbelt, Md. "The UVOT data show that Lulin was shedding nearly 800 gallons of water each second." That's enough to fill an Olympic-size swimming pool in less than 15 minutes.

Swift can't see water directly. But ultraviolet light from the sun quickly breaks apart water molecules into hydrogen atoms and hydroxyl (OH) molecules. Swift's UVOT detects the hydroxyl molecules, and its images of Lulin reveal a hydroxyl cloud spanning nearly 250,000 miles, or slightly greater than the distance between Earth and the moon.

"Dirty Snowball" came close last night

"We won't be able to send a space probe to Comet Lulin, but Swift is giving us some of the information we would get from just such a mission," said Jenny Carter, at the University of Leicester, U.K., who is leading the study.

"The comet is releasing a great amount of gas, which makes it an ideal target for X-ray observations," said Andrew Read, also at Leicester.

A comet is a clump of frozen gases mixed with dust. These "dirty snowballs" cast off gas and dust whenever they venture near the sun. Comet Lulin, which is formally known as C/2007 N3, was discovered last year by astronomers at Taiwan's Lulin Observatory. The comet is now faintly visible from a dark site. Lulin will pass closest to Earth -- 38 million miles, or about 160 times farther than the moon -- late on the evening of Feb. 23 for North America.

On Jan. 28, Swift trained its Ultraviolet/Optical Telescope (UVOT) and X-Ray Telescope (XRT) on Comet Lulin. "The comet is quite active," said team member Dennis Bodewits, a NASA Postdoctoral Fellow at the Goddard Space Flight Center in Greenbelt, Md. "The UVOT data show that Lulin was shedding nearly 800 gallons of water each second." That's enough to fill an Olympic-size swimming pool in less than 15 minutes.

Swift can't see water directly. But ultraviolet light from the sun quickly breaks apart water molecules into hydrogen atoms and hydroxyl (OH) molecules. Swift's UVOT detects the hydroxyl molecules, and its images of Lulin reveal a hydroxyl cloud spanning nearly 250,000 miles, or slightly greater than the distance between Earth and the moon.