NASA asteroid-hunting project spots new comet — and maybe a 2nd

A space-hunting program has spotted what could be two new comets, one that will pass Earth in February.

These newly discovered celestial objects pose no threat Earth, astronomers say

An artist’s rendition of 2016 WF9 as it passes Jupiter’s orbit inbound toward the sun. Credits: (NASA/JPL-Caltech)

A space-hunting program has spotted what could be two new comets, with one that will pass Earth in February.

The first object, called 2016 WF9, was found Nov. 27. At its farthest, it nears the orbit of Jupiter. It takes about 4.9 years for one complete orbit, which will eventually bring it within Earth's orbit.

The discovery was made by NASA's NEOWISE program (Near-Earth Object Wide-field Infrared Survey Explorer) an asteroid-hunting project.

Astronomers are unsure about whether 2016 WF9 is an asteroid or a comet. Comets are icy, dusty material left over from the formation of the solar system, while asteroids are rocky or metallic in nature. In this case, the newly discovered object reflects light like a comet, and orbits like a comet, but it doesn't possess the gas cloud of a comet.

As comets near the sun, the frozen material warms and sublimates, transitioning from solid to a gas, producing the tail we associated with them.

In a statement, NEOWISE deputy principal investigator James "Gerbs" Bauer at NASA's Jet Propulsion Laboratory said 2016 WF9 "could have cometary origins. This object illustrates that the boundary between asteroids and comets is a blurry one; perhaps over time this object has lost the majority of the volatiles that linger on or just under its surface."

Definitely a comet

The object — which astronomers have measured to be between 0.5 to 1 kilometre wide — will come within 51 million kilometres of Earth on Feb. 25. Though that may seem near, astronomers stress that it poses no danger to Earth now, or in the foreseeable future.

But another object was also discovered. This second one is definitely a comet, as it's already releasing dust as it nears the sun. The name of the comet is C/2016 U1 NEOWISE, and it could become a potential binocular target as it nears Earth. However, the brightness of comets can be tricky to predict, so scientists can't say definitively that it will be a great sight.

If it does brighten so that it can be seen in binoculars, it will be visible in the northern hemisphere, in the southeastern sky just before sunrise during the first week of January.

The comet will reach its closest point to the sun in its orbit on Jan. 14. After that, it heads back out to the outer solar system in an orbit that takes thousands of years. And again, it poses no threat to Earth.