A stormfrom the sun ripped a tail off a comet, and a NASA satellite captured the wholeevent.
Thespectacular cosmic crash occurred on April 20 when the sun cast out a coronalmass ejection (CME), or large cloud of magnetized gas. The tempest wasthrust directly in the path of Comet Encke,which was traveling around the sun, within the orbit of Mercury. As the gasswept over the comet, its tail brightened and then was separated completelyfrom its parent icy rock and carried away.
NASA's pairof Solar Terrestrial Relations Observatory (STEREO) satellites captured thewhole incident in newly released imagesand video.
"Wewere awestruck when we saw these images," said Angelos Vourlidas of theNaval Research Laboratory. "This is the first time we've witnessed acollision between a coronal mass ejection and a comet, and the surprise ofseeing the disconnection of the tail was the icing on the cake."
Comets areicy leftovers from the solar system's formation billions of years ago. Theyoccasionally detour from their home in the cold, distant regions of the solarsystem, after a gravitational tug from a planet or another comet sends theminto the inner solar system.
The sun'sheat vaporizes gas and dust from the ice core of the comet, forming its tail.
CMEs areviolent eruptions on the sun, with masses upwards of a few billion tonstraveling anywhere from 62 to 1,864 miles per second (100 to 3,000 kilometersper second). They can cause geomagneticstorms in the Earth's atmosphere, which can disrupt satellite and radiocommunications and sometimes disable satellites.
Whilescientists were aware that a comet's tail would occasionally completelydisconnect and suspected CMEs were the culprit, this is the first observationof the violent event.
The NASAobservations are detailed in the Oct. 10 issue of Atmospheric JournalLetters.
Anotherstudy announced today showed comets can sometimes slowthe solar wind down, too.
- Video: See Comet's Tail Ripped Off
- Comets Through Time: Myths and Mystery
- Images: Comets
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