Car-sized asteroid called 2020 HQ nearly hit Earth on Sunday

• A car-sized asteroid flew about 1,830 miles from Earth this weekend – closer than any known space rock has ever crashed onto the planet.
• A NASA-funded program detected the asteroid, called 2020 HQ, six hours after it approached shutdown.
• If the asteroid had struck Earth, it likely would have exploded in the atmosphere in an aerial explosion too high to cause damage to the ground.
• But the near miss highlights a major blind spot in Earth’s programs to search for dangerous asteroids.
• Visit the Business Insider homepage for more stories.

A car-sized asteroid flew about 2,950 kilometers from Earth on Sunday.

It’s a remarkably close shave – the closest ever recorded, in fact, according to asteroid trackers and a catalog compiled by the Sormano Astronomical Observatory in Italy.

Due to its size, space rock would probably not have posed a danger to people on the ground if it had hit our planet. But the close call is worrying nonetheless, as astronomers had no idea the asteroid existed before it passed.

“The asteroid approached undetected from the direction of the sun,” Paul Chodas, director of NASA’s Center for Near Earth Object Studies, told Business Insider. “We didn’t see it coming.”

Instead, the Palomar Observatory in California first detected the space rock around six hours. after it flew over the Earth.

Chodas confirmed the record-breaking nature of the event: “Yesterday’s close-in approach is the closest ever recorded, aside from a few known asteroids that have indeed had an impact on our planet,” he said. declared.

NASA knows only a fraction of near-Earth objects (NEOs) like this one. Many do not cross the line of sight of any telescope, and several potentially dangerous asteroids have sneaked up on scientists in recent years. If the bad one gets through the loopholes in our near-Earth object surveillance systems, it could kill tens of thousands of people.

2020 HQ flew over the southern hemisphere

This recent near-Earth asteroid was originally called ZTF0DxQ, but is now officially known to astronomers as 2020 HQ. Business Insider was first informed of this by Tony Dunn, the creator of orbitsimulator.com.

“The newly discovered asteroid ZTF0DxQ exceeded less than 1/4 in diameter from Earth yesterday, making it the closest known flyover that has not hit our planet,” Dunn tweeted Monday. He shared the animation below, reposted here with permission.

The accelerated simulation shows the approximate orbital trajectory of HQ 2020 as it moved at a speed of approximately 7.7 miles per second (12.4 kilometers per second) or approximately 27,600 mph.

Early observations suggest the space rock flew over the southern hemisphere just after 4 a.m. universal time (midnight ET) on Sunday.

The animation above shows 2020 HQ flying over the Southern Ocean near Antarctica. However, the Minor Planet Center of the International Astronomical Union calculated a slightly different trajectory. The group’s rendering (shown at the start of this story) suggests that the asteroid flew over the Pacific Ocean hundreds of kilometers east of Australia.

Not dangerous, but definitely not welcome

When it comes to space rocks, 2020 HQ wasn’t too dangerous.

Observations from the telescope suggest the object is between 6 feet (2 meters) and 18 feet (5.5 meters) wide – somewhere between the size of a small car and an extended cab pickup truck. But even though it was on the larger end of that spectrum and made of dense iron (most asteroids are rocky), only small pieces of such an asteroid can have reached the ground, according to the “Impact Earth” simulator. from Purdue University and Imperial. College of London.

Such an asteroid would have exploded in the atmosphere, creating a brilliant fireball and triggering an aerial explosion equivalent to the explosion of a few tens of kilotons of TNT. It’s pretty much the same as one of the atomic bombs the United States dropped on Japan in 1945. But the aerial explosion would have happened about 2-3 miles above the ground, so it wouldn’t have sounded louder than the heavy traffic towards people on the ground. .

That doesn’t make the asteroid’s discovery much less baffling, however – it doesn’t take a huge space rock to create a big problem.

Darrel Robertson / NASA Ames

Take, for example, the approximately 20-meter-wide asteroid that exploded without warning over Chelyabinsk, Russia in February 2013. This space rock created a superbolid event, triggering an aerial explosion equivalent to 500 kilotons of TNT – about 30 Energy from Hiroshima’s nuclear bombs. The explosion, which began about 20 kilometers above Earth, triggered a shock wave that shattered the windows of six Russian cities and injured around 1,500 people.

And in July 2019, a 130-meter (427-foot) asteroid called 2019 OK passed within 72,400 kilometers of our planet, less than 20 percent of the distance between Earth and the Moon. Astronomers detected the rock less than a week before its closest approach, prompting a scientist to tell the Washington Post that the asteroid essentially appeared “out of nowhere.”

In an unlikely direct impact on a city, such a capricious space rock could kill tens of thousands of people.

NASA is actively scanning the skies for such threats, as Congress has demanded since 2005. However, the agency is mandated to detect only 90% of “city killer” space rocks over 140 meters in diameter.

In May 2019, NASA said it had found less than half of the estimated 25,000 objects of this size or more. And of course, that doesn’t count the smaller rocks such as the Chelyabinsk asteroids and 2019 OK.

Objects coming from the direction of the sun, on the other hand – like 2020 HQ – are notoriously difficult to spot.

“There isn’t much we can do to detect incoming asteroids coming from the direction of the sun, as asteroids are detected using optical telescopes only (like ZTF), and we can only search for them in the night sky. “said Chodas. “The idea is that we find them out on one of their previous passages through our planet, and then make predictions years and decades in advance to see if they have any possibility of impact.”

NASA has a plan to fill these gaps in its asteroid hunting program. The agency is in the early stages of developing a space telescope capable of detecting asteroids and comets coming from the direction of the sun. NASA’s 2020 budget allocated nearly $ 36 million for this telescope, called the Near Earth Object Surveillance Mission. If funding continues, it could be launched as early as 2025.

This story has been updated with new information.