Astrophysicist Josep Trigo-Rodriguez of the Institute of Space Sciences near Barcelona, Spain, believes it is an interstellar object based on its odd path and extreme speed cutting through the solar system. He estimates its size at roughly 25 miles (40 kilometers) across.

It's only the third time that experts have spotted an object in the Milky Way that's come from a different solar system. Find out more here.

Astronomers have observed an object that originated from beyond our solar system, thought to be an interstellar comet, speeding through our celestial neighborhood.