A massive asteroid is expected to whiz by Earth in a relatively close encounter – 4.5 million miles –  on Tuesday, according to NASA’s Jet Propulsion Laboratory.

The asteroid, known as 2021 KT1, is about 600 feet, the size of the New York Olympic Tower or the Seattle Space Needle.

NASA classified the asteroid as a “potentially hazardous object” because it is larger than 492 feet and within 4.6 million miles of Earth. It will fly near Earth at 40,000 mph, according to the laboratory, which tracks objects that drift close to Earth’s orbital area. Though the asteroid is not expected to make a direct hit, NASA is keeping a close watch.

This asteroid is not the only one to come close to the Earth. An asteroid known as 2021 GW4 was 12,000 miles away from the Earth’s surface, traveling 18,700 mph in April. Astronomer Gianluca Masi, founder of the Virtual Telescope project, said it was “an exceptionally close encounter.”