NASA’s NEOWISE mission is currently working in its extended phase and it has detected at least one comet late last year and another body, an asteroid or a comet, which are hurtling towards Earth.
NEOWISE mission detected object has been named 2016 WF9 on November 27 last year and as described by NASA, the object has an orbit that provides it with rather a scenic tour of our solar system. The object hasn’t been placed in any of the categories yet – asteroid or comet. 2016 WF9, at its farthest distance from the Sun, approaches Jupiter’s orbit and as it travels inward over the course of 4.9 Earth-years it passes 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.
2016 WF9 will approach Earth’s orbit on February 25 this year. At a distance of nearly 51 million kilometres 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.
NASA explains that objects similar to 2016 WF9 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 is relatively large: roughly 0.5 to 1 kilometre across. It is also rather dark, reflecting only a few percent of the light that falls on its surface. This body resembles a comet in its reflectivity and orbit, but appears to lack the characteristic dust and gas cloud that defines a comet.
There is another object as well that was discovered in early December 2016, and it is clearly a comet.
C/2016 U1 NEOWISE
This particular comet could be visible from Earth using a good pair of binoculars, NASA has said. However, the visibility isn’t guaranteed because the space agency isn’t able to predict the comet’s brightness. To spot this particular comet from the northern hemisphere, you will have to look towards the southeastern sky shortly before dawn. The comet is moving farther away in the south with each passing day and once it reaches its closest point to the Sun on January 14 it will start an outward journey that will take it beyond the outer solar system and won’t be visible for thousands of years to come.