By Will Dunham WASHINGTON (Reuters) -Astronomers are tracking a newly spotted comet hailing from parts unknown, only the third time such an interstellar object has been observed visiting our solar system.

Officially named 3I/ATLAS, the comet was confirmed as having originated outside of Earth's solar system on July 3, according to the European Space Agency (ESA) and NASA. It is believed to be about 20 kilometers, or over 12 miles wide, according to the ESA and traveling at about 60 kilometers, or 37 miles per second relative to the sun.

Astronomers have discovered a rare instance of a interstellar comet speeding through the solar system. The 3I/ATLAS was first spotted on July 1 by the NASA-funded Asteroid Terrestrial-impact Last Alert System telescope.