Tue, Mar 21, 2023
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Tech & Science

A "City-Killer" Asteroid Just Missed Hitting Earth Today

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Tech & Science Asteroid Astronomy Science

Earth nearly had a devastating collision with an asteroid travelling at nearly 15 miles a second today.

Asteroid 2019 OK, estimated to be between 187 feet and 427 feet in diameter, came within 43,500 miles of striking the Earth — closer than the moon.

The asteroid was flying towards us towards the direction of the sun, making it hard to spot. It was only first seen a few days ago, and was only confirmed to be an asteroid in the past day.

Vesta Giant Asteroid
This is the Vesta Asteroid, in a photograph taken in 2011 by the NASA Dawn spacecraft. This is one of the best known photographs of an asteroid, in this case, taken from only 3,200 miles above the surface. NASA/Getty

"It's impressively close. I don't think it's quite sunk in yet. It's a pretty big deal," Associate Professor Michael Brown of Monash University's school of physics and astronomy told the Sydney Morning Herald.

Had the asteroid hit, the impact would have been comparable to the explosion of a nuclear weapon.

"It would have hit with over 30 times the energy of the atomic blast at Hiroshima," Swinburne University astronomer Alan Duffy told the paper, calling it a "city-killer asteroid."

nasa diagram Asteroid 2019 OK
A NASA diagram shows how close Asteroid 2019 OK came within hitting the Earth today. The blue line depicts the Earth's orbit, the white circle is the Moon's orbit and the white line is a close-up of Asteroid 2019 OK's orbit. NASA

Brown said that today's incident was one of the closest known approaches to Earth by an asteroid. The asteroid was so close that if someone were looking at the right spot in the sky, they would be able to see it using only binoculars.

Though the asteroid could have been devastating if it hit the earth, it doesn't compare to the asteroid that wiped out the dinosaurs, which was nearly 10 miles across. Earth itself is just over 7,900 miles in diameter.

According to NASA, Asteroid 2019 OK has been near Earth before, but never so close. Its last visit was February 1, 2017, though it was over 25 million miles away from the surface of Earth. It is next expected to come within 46 million miles of Earth in 2024. For reference, the sun is about 93 million miles away from our planet.

The asteroid was one of four that flew by Earth Wednesday, though Asteroid 2019 OK was the closest and largest. Asteroid HM10 passed Earth by 2.9 million miles, Asteroid 2019 OD was 219,375 miles from Earth's surface, and finally, Asteroid 2019 OE came within 602,000 miles from Earth, or about two and a half times the distance between Earth and the Moon. Of the three other rocks, Asteroid 2019 OD was the largest, believed to be between 170 feet and 393 feet across.

Though Asteroid 2019 OK was in no danger of actually hitting Earth, experts say that with enough notice of an incoming asteroid, it may be possible to nudge the asteroid's orbit slightly, making it miss our planet.

While it's a common solution in films like Armageddon and Deep Impact to blow up an asteroid to keep it from striking Earth, this is not an option in real life. While a nuclear bomb could indeed destroy an asteroid, NASA says it's likely that large pieces of the destroyed rock would still strike the planet and do massive damage.

This article has been updated after Michael Brown reached out to say he'd misspoke, and the asteroid was flying towards the sun, not away from it.

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