Asteroid set to fly by Earth today
19 April 2017 Last updated at 06:39 BST
An asteroid called 2014 JO25 is due to fly past the Earth today.
Don't worry - Nasa has said there is no danger that the rock will hit our planet! In fact, it will pass us at a distance of 1.1 million miles away.
It is the first time that the asteroid has flown near to Earth like this for 400 years - and it doesn't plan on coming back for another 500 years - so scientists are looking forward to studying it as it sails past.
Martin has been finding out more...
Pictures courtesy of Nasa