Scientists believe they have found an asteroid unlike any other.
It is only 400 metres across, but it is moving incredibly fast - more than 20,000 metres per second!
It was first discovered by scientists from the University of Hawaii Institute for Astronomy on October 19.
They have a telescope that can move and track the sky very quickly.
Asteroids and comets from inside our solar system rarely travel as quickly as this alien asteroid.
Because the object was travelling so quickly, scientists believe that it must have come from outside our solar system.
The gravitational pull of very large stars and planets helped the asteroid, named A/2017 U1 by scientists, to move faster and faster.
A/2017 U1 is the first of its kind to be discovered by scientists, who have been waiting for a long time to track an asteroid from outside our solar system.
It has already orbited the Sun and passed by the Earth. Now it is moving towards a group of stars called the Pegasus constellation.