A space rock about the size of Navy Pier will be passing by Earth tonight, Friday, March 4th.

The asteroid known as 138971 measures around 560 meters to 1.2 kilometers in diameter. And for some reason, space experts are using iconic Chicago locations to measure the rock by saying it’s between the sizes of The Sears Tower and Navy Pier.

NASA will be tracking the asteroid and you can watch it in real-time as it travels past our planet. The asteroid poses no threat to Earth.

Source: Concho Valley