This weekend an Asteroid known as 1999 KW4 is going to pass by Earth at around 7:05 p.m. ET on Saturday.

1999 KW4 is about 1 mile big in diameter and it has it's own moon with about 0.3 miles size. This will be one of the closest encounters of Earth with other space objects in recent history. 

At their closest to Earth moment, they will be about 3 milion miles away. This is far enough for us not to be able to see them with naked eye.

Next time we will be able to see them again will be in about 17 years from now. So if you don't want to miss the oprotunity, prepare your telescopes.