An icy ‘Oumuamua may have lost enormous amounts of material during a journey lasting hundreds of millions of years between ...

When the first object ever known to have visited the Earth's Solar System from outer space zoomed past in 2017, it was so strange that at least one leading astronomer was convinced it was an alien ...

In 2017, ‘Oumuamua appeared in the sky as the first confirmed interstellar object. We still aren't entirely certain what ‘Oumuamua was—though we can be mostly certain it wasn't an alien spacecraft.