A/2017 U1 is the codename given to a fast-moving object that’s currently doing the rounds across the Solar System.

The object is about a quarter of a mile in size, moving at about 15.8 miles per second on a strong hyperbolic orbit (that is, it is moving fast enough to escape the gravitational pull of the sun). The only problem is, astronomers don’t know exactly what A/2017 U1 actually is.

The object was first spotted by the University of Hawaii’s Pan-STARRS 1 telescope on Haleakala, Hawaii on October 19. STARSS 1 has been tracking the unidentified object since.

Early observations have determined that A/2017 U1’s composition is similar to that from celestial bodies found in the Kuiper Belt, a region beyond Neptune that contains remnants from the formation of the Solar System.

The trajectory of A/2017 U1 seems to suggest that it entered the Solar System from above. Researchers have postulated that the object may have originated from elsewhere in the galaxy, which would make A/2017 U1 the very first known visitor from outer space.

Astronomers will keep tracking this peculiar phenomenon to ascertain whether or not the object is extraneous to the Solar System.