Scientists at JPL have their eyes on two objects, one that will come within 32 million miles of Earth as it enters our orbit and another that is already in Earth’s orbit.
Comet C/2016 U1 NEOWISE, which is currently traveling in our orbit, will be in the southeastern sky shortly before dawn prior to heading back to the outer reaches of the solar system in an orbit trajectory lasting thousands of years.
“[The comet] has a good chance of becoming visible through a good pair of binoculars, although we can’t be sure because a comet’s brightness is notoriously unpredictable,” said Paul Chodas, manager of NASA’s Center for Near-Earth Object (NEO) Studies at JPL.
Meanwhile, 2016 WF9 will approach Earth’s orbit on Feb. 25 and come within less than 100 million miles of Earth. The object is estimated to be roughly .3 to .6 miles in size. According to JPL, its body resembles a comet in its reflectivity and orbit, but appears to lack the characteristic dust and gas cloud that defines a comet.
“This object illustrates that the boundary between asteroids and comets is a blurry one,” Deputy Principal Investigator James Bauer at JPL said in a prepared statement. “Perhaps over time this object has lost the majority of the volatiles that linger on or just under its surface.”
NEOWISE is the asteroid-and-comet-hunting portion of the Wide-Field Infrared Survey Explorer (WISE) mission. After discovering more than 34,000 asteroids during its original mission, NEOWISE was brought out of hibernation in December 2013 to find and learn more about asteroids and comets that could pose an impact hazard to Earth. If 2016 WF9 turns out to be a comet, it would be the 10th discovered since reactivation. If it turns out to be an asteroid, it would be the 100th discovered since reactivation.
NEOWISE data have been used to measure the size of each near-Earth object it observes. Thirty-one asteroids that NEOWISE has discovered pass within about 20 lunar distances from Earth’s orbit, and 19 are more than 460 feet in size but reflect less than 10 percent of the sunlight that falls on them.