It’s the name of a small celestial body that crossed our solar system a few years ago.
The Haleakala Observatory, in Hawaii, was the first to spot it in October 2017.
Astronomers gave it a Hawaiian name, Oumuamua, which means “messenger”.
So, what’s all the fuss about?
It’s the first time that an object from somewhere else has been observed in our solar system.
Scientists were surprised by its long shape – like a baguette.
And by its behaviour too. The little intruder went around the Sun and then accelerated away.
Exactly like a comet! When they approach the Sun, their ice melts, forming a tail and making them speed up.
However, no one observed a tail behind Oumuamua… So what sort of object could it be?
Avi Loeb, a famous American astrophysicist, said it could be an alien spaceship equipped with a light-sail.
Most other scientists, on the other hand, think this mysterious celestial body was a comet or a type of asteroid we don’t know about.
Oumuamua, headed off into deep space without giving us a chance to study it better.
So, astronomers hope that a similar object will visit us again soon to give us more knowledge about what’s beyond our solar system.