Asteroid the Size of Two Empire State Buildings Nearing Earth

A massive asteroid that could be twice as wide as the Empire State Building will speed past Earth on Thursday, April 28.

The asteroid—designated 418135 (2008 AG33), with a width estimated to be between around 1,150 and 2,560 feet—will be traveling at speeds approaching an incredible 23,264 miles per hour.

To put that into perspective, that speed is 11 times faster than a bullet fired by a rifle at around 2,050 miles per hour, and 27 times as fast as a bullet fired by the average handgun, at about 859 miles per hour.

The asteroid will be traveling at over 30 times the speed of sound, 767 miles per hour, and 15 times faster than the maximum speed of a Lockheed Martin F-16 jet fighter which is around 1,500 miles per hour.

Asteroid passes close to Earth
A stock image of an asteroid passing close to Earth. On April 28 an asteroid potentially twice the size of the Empire State Building will race past Earth at many times the speed of sound. dottedhippo/GETTY

In terms of distance, at its closest approach on Thursday 418135 (2008 AG33) will get to about two million miles from Earth, or about eight and a half times as distant as the average gap between the Earth and the Moon (which according to the Royal Museums Greenwich is about 238,855 miles).

The asteroid will come much closer to Earth than Mars, however, as the average distance between our planet and the famous Red Planet is 140 million miles according to NASA.

It was first discovered by the Mt. Lemmon Survey conducted at the Mount Lemmon observatory in Arizona on January 12, 2008. NASA's Center for Near Earth Object Studies (CNEOS) within the Jet Propulsion Laboratory at the California Institute of Technology estimates that 418135 (2008 AG33) last paid a close visit to Earth on March 1, 2015.

Following this current visit, the asteroid usually visits our region of space roughly every seventh year, and will not return to Earth's vicinity until May 25, 2029. Following this, 418135 (2008 AG33) won't return until February 9, 2045.

During its 2045 visit, the asteroid will be much more distant, passing earth at a distance of around 45,000,000 miles. During this particular approach, the asteroid will be traveling at a much greater speed of around 42,345 mph, about 55 times the speed of sound.

Asteroid 418135 (2008 AG33) won't be the only massive space rock whipping past our planet in the near future. On May 29, 467460 (2006 JF42) with an estimated size of between 1,246 and 2,821 feet will pass Earth at a distance of around 3.5 million miles.

This potentially larger asteroid will also be traveling at an impressive speed, zipping past Earth at around 25,277 mph.

Asteroid 467460 (2006 JF42) was discovered in 2006, and is a much more frequent visitor to Earth, passing approximately once a year but occasionally taking a four-year break between flybys.