* Astronomy

NASA's NEOWISE Mission Spies One Comet, Maybe Two

NASA's NEOWISE mission has recently discovered some celestial objects travelling through our neighbourhood, including one on the blurry line between asteroid and comet. Another--definitely a comet--might be seen with binoculars through next week.
An object called 2016 WF9 was detected by the NEOWISE project on Nov. 27, 2016. It's in an orbit that takes it on a scenic tour of our solar system. At its farthest distance from the sun, it approaches Jupiter's orbit. Over the course of 4.9 Earth-years, it travels inward, passing under the main asteroid belt and the orbit of Mars until it swings just inside Earth's own orbit. After that, it heads back toward the outer solar system. Objects in these types of orbits have multiple possible origins; it might once have been a comet, or it could have strayed from a population of dark objects in the main asteroid belt.
2016 WF9 will approach Earth's orbit on Feb. 25, 2017. At a distance of nearly 51 million kilometers from Earth, this pass will not bring it particularly close. The trajectory of 2016 WF9 is well understood, and the object is not a threat to Earth for the foreseeable future.
Read more