Year in Review: Visitor from the Oort cloud
Comet ISON meets demise in solar flyby
SHORT LIVED Comet ISON starts as a streak (left), disappears into the sun’s corona (red) and fades (right) as it emerges from the close encounter. This composite, time-lapse image shows the comet’s path from November 28 to December 1.
SDO/SOHO/ESA & NASA
22
Comet ISON was an ordinary-sized comet with an extraordinary story. It started out millions of years ago in the faraway Oort cloud (SN: 10/19/13, p. 19), where remnants of the early solar system hang out in deep freeze. A passing star may have given one of these remnants a nudge, launching it on a journey that would bring it to within 1.2 million kilometers of the sun in 2013.
Two astronomers with the International Science Optical Network discovered the remnant in September 2012, while it was still outside Jupiter’s orbit. Scientists quickly realized that ISON would be the first known Oort cloud object to pass near the sun. The sun’s light and heat would vaporize this fossil of the
