Researchers using a powerful telescope in Hawaii spotted the visiting object, called A/2017 U1, last week. “We have been waiting for this day for decades,” said Paul Chodas, manager of the Center for Near-Earth Object Studies at the NASA’s Jet Propulsion Laboratory in Pasadena, California, in a statement. “It’s long been theorized that such objects exist–asteroids or comets moving around between the stars and occasionally passing through our solar system–but this is the first such detection.”
According to Space.com, when it was first observed, scientists at first assumed it was a comet but later noticed that it lacked the telltale signs of a comet—the cloud of gas and dust surrounding its core—so they changed its designation. How do they know it comes from far, far away? Due to its hyperbolic orbit, which is directing the object out of the solar system. While not a comet, some researchers think it’s probably just ice—and not an asteroid or E.T. —that was ejected out of another solar system into space.