NASA’s reinvigorated Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) spacecraft has discovered its first previously unknown comet since its reboot last year. But it turns out that this particular "dirty snowball" is a little… different.
“This comet is a weirdo,” said NEOWISE principal investigator Amy Mainzer, of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “It is in a retrograde orbit, meaning that it orbits the sun in the opposite sense from Earth and the other planets.”
C/2014 C3 (NEOWISE) was spotted by the mission on Feb. 14 when it was approximately 143 million miles from Earth. To give a sense of scale, that’s nearly five times the distance from Earth to Mars when the planets are at their closest points in orbit. NEOWISE was able to track the "new" comet six times over half a day before the object moved out of the mission’s field of view. The discovery was then confirmed through observations by the Near Earth Object Observation project, Spacewatch, in Tucson, Ariz. three days later.
Although this is the first comet discovery of the new NEOWISE mission, the infrared space telescope discovered 21 other comets during its primary mission between 2009 and 2011 before its cryogenic hydrogen depleted. In September, the mission was switched back on to asteroid- (and now comet-) hunting duties — a task it can easily fulfill without the ultra-low temperatures its onboard coolant provided.
NEOWISE is a critical tool in discovering new asteroids and comets, as well as characterizing known objects — a population of near-Earth objects that stray close to Earth.
More on the rebooted NEOWISE mission: