Houston, we have a visitor—and astronomers think there could be 10,000 more just like it "lurking" in wait, as the Guardian puts it.
Meet 1I/2017 U1, or 'Oumuamua (Hawaiian for "messenger" or "scout"), which scientists say is an asteroid from another solar system—a cosmic first for observers on Earth. CNN notes the "oddball" 'Oumuamua first caught Hawaiian astronomers' attention as it was hurtling through our solar system last month, and using telescopes, they've determined it's probably not so different than our native asteroids and comets.
And because asteroids start to take shape around a particular planet as it forms, that hints there may be other planets not too different from our own in other solar systems. "For decades we've theorized that such interstellar objects are out there, and now—for the first time—we have direct evidence they exist," a NASA rep says in a statement.