BLUF:
NASA knows about only a fraction of near-Earth objects (NEOs) like this one. Many do not cross any telescope’s line of sight, and several potentially dangerous asteroids have snuck up on scientists in recent years.
If the wrong one slipped through the gaps in our NEO-surveillance systems, it could kill tens of thousands of people.
An Asteroid Just Made The Closest Earth Fly-by on Record, And We Didn’t See It Coming.
A car-size asteroid flew within about 1,830 miles (2,950 kilometers) of Earth on Sunday.
That’s a remarkably close shave – the closest ever recorded, in fact, according to asteroid trackers and a catalogue compiled by Sormano Astronomical Observatory in Italy.
Because of its size, the space rock most likely wouldn’t have posed any danger to people on the ground had it struck our planet. But the close call is worrisome nonetheless, since astronomers had no idea the asteroid existed until after it passed by.
“The asteroid approached undetected from the direction of the Sun,” Paul Chodas, the director of NASA’s Centre 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 about six hours after it flew by Earth.
Chodas confirmed the record-breaking nature of the event: “Yesterday’s close approach is closest on record, if you discount a few known asteroids that have actually impacted our planet,” he said.
NASA knows about only a fraction of near-Earth objects (NEOs) like this one. Many do not cross any telescope’s line of sight, and several potentially dangerous asteroids have snuck up on scientists in recent years.
If the wrong one slipped through the gaps in our NEO-surveillance systems, it could kill tens of thousands of people.
2020 QG flew over the Southern Hemisphere
This recent near-Earth asteroid was initially called ZTF0DxQ but is now formally known to astronomers as 2020 QG. Business Insider first learned about it from Tony Dunn, the creator of the website orbitsimulator.com.
“Newly-discovered asteroid ZTF0DxQ passed less than 1/4 Earth diameter yesterday, making it the closest-known flyby that didn’t hit our planet,” Dunn tweeted on Monday.
He shared the animation below, republished here with permission.
The sped-up simulation shows the approximate orbital path of 2020 QG as it careened by at a speed of about 7.7 miles per second (12.4 kilometers per second) or about 27,600 mph (44,000 km/h).
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 QG flying over the Southern Ocean near Antarctica.
However, the International Astronomical Union’s Minor Planet Centre calculated a slightly different trajectory. The group’s rendering (shown below), suggests the asteroid flew over the Pacific Ocean hundreds of miles east of Australia.
Not dangerous, but definitely not welcome
As far as space rocks go, 2020 QG wasn’t too dangerous.
Telescope observations 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 if it was on the largest end of that spectrum and made of dense iron (most asteroids are rocky), only small pieces of such an asteroid may have reached the ground, according to the “Impact Earth” simulator from Purdue University and Imperial College London.