Comet ISON Spotted by NASA's Deep Impact


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NASA's Deep Impact spacecraft has snapped several images of the comet ISON (C/2012 S1). The images were obtained over 36 hours on January 17 and 18, from a distance of 793 million km (493 million miles). The comet is expected to come within 1.8 million km (1.1 million miles) of the sun and burn bright enough to be seen from Earth with the naked eye.

"This is the fourth comet on which we have performed science observations and the farthest point from Earth from which we've tried to transmit data on a comet," said Tim Larson, project manager for Deep Impact at NASA's Jet Propulsion Laboratory (JPL). "The distance limits our bandwidth, so it's a little like communicating through a modem after being used to DSL. But we're going to coordinate our science collection and playback so we maximize our return on this potentially spectacular comet."

Comet ISON was only just discovered in September of 2012 by Russian astronomers. NASA has determined that the comet is making its first-ever journey into the the inner solar system. Researchers believe that means the object's surface will have plenty of volatile material that will be burned off by the sun. Long-period comets such as ISON come from the Oort cloud, a cloud of icy objects that surround the solar system at an incredible distance - as far away as one-third the distance to the Sun's nearest neighbor star.

NASA has stated that there is no chance comet ISON will be a risk to the Earth. The object's closest approach to the planet will be on December 26, 2013, and the comet's head and tail should be visible during its closest approach to the sun.

In addition to the visible light images seen below, data from Deep Impact is expected to provide researchers with infrared data and light curves for the comet. Though the object is currently over 763 million km (474 million miles) from the Sun, its tail is already estimated to be over 64,400 km (40,000 miles) long.

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NASA Jet Propulsion Laboratory California Institute of Technology