On February 25, NASA officials say that an object they call 2016 WF9 is due to fly past our planet.
It was first detected by the administration's asteroid-hunting NEOWISE project on November 27 of last year, and it is believed to be around 1 kilometer (0.6 miles) across. We most likely have nothing to worry about, as it shouldn't come closer than roughly 32 million miles away from Earth. The problem is, though, that scientists haven't been able to identify it.
It's possible that 2016 WF9 is an asteroid or comet, but it doesn't completely fit the characteristics of either one. Asteroids -- like the one pictured below -- tend to be rocky or metallic, while comets are usually icier.
According to scientists, the mystery object resembles a comet more because it is dark and not very reflective, but it lacks the dust and gas cloud that accompanies them.
"2016 WF9 could have cometary origins," Deputy Principal Investigator James "Gerbs" Bauer from the NASA Jet Propulsion Laboratory said. "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."