‘Planet killer’ asteroid with potential to collide with Earth found hiding in sun’s glare

For a long time, the sun’s glare has hidden a secret: a trio of space rocks with one member that could one day be dangerous to the planet. Of the three asteroids recently discovered by astronomers, two are so massive they’ve been described as “planet killers” — and one has the potential to cross Earth’s orbit, according to one new study.

The region between the orbits of Earth and Venus is often obscured by the sun’s glare, making it “notoriously challenging” for astronomers to observe what lurks in the region, scientists say. But recently, astronomers were able to get around the challenge by conducting two 10-minute windows overnight.

And what they found was well worth the wait. Hidden behind that brilliance was a trio of asteroids near Earthmeaning gravity has pushed them into orbits that “allow them to enter Earth’s environment,” according to NASA’s Center for Near Earth Object Studies.

The three asteroids are named 2021 LJ4, 2021 PH27 and 2022 AP7. The first of the three is small and in orbit that is safe and “fully within Earth’s orbit”. Because of the sun, only about 25 asteroids with this type of orbit have been discovered so far, astronomers said in a press release. 2021 PH27 also falls into this category, with one distinction: it is much larger.

2021 PH27 is between 0.9 and 1.7 kilometers (0.5 to 1 mile) in diameter and is the closest known asteroid to the sun, according to a press release from Noir Lab, causing the surface to become so hot that the lead can melt. There are “probably several” asteroids of this size and type in the region, researchers said in their study.

“Our twilight survey searches the area within the orbits of Earth and Venus in search of asteroids,” said astronomer Scott Sheppard, the lead author of the new study. “So far we have found two large near-Earth asteroids with a diameter of about 1 kilometer, a size we call planet killers.”

The third and final asteroid newly discovered is 2022 AP7, and unlike its other trio members, it has the power to deliver a more powerful blow to the planet. This asteroid is larger than 2021 PH27, with a diameter of just under a mile. It’s an Apollo asteroid, which means it’s an… orbit path that could one day force it to come into contact with Earth.

It’s also the largest object potentially dangerous for the planet to be discovered in about eight years, researchers said.

“Over time, this asteroid will get brighter and brighter in the sky as it starts to cross Earth’s orbit closer and closer to where Earth is,” Sheppard told The New York Times. “…This is what we call a planet killer. If it hits the Earth, it would destroy the entire planet. It would be very bad for life as we know it.”

But planetary scientists Tracy Becker told The Times that such an incident in the “foreseeable future” has “extremely low probability.”

And now the hunt for more asteroids continues with the help of the Dark Energy Camera (DECam), which uses highly sensitive and high-tech technology to capture large swathes of the space sky.

“Large areas of the sky are needed because inner asteroids are rare, and deep images are needed because asteroids are faint and you’re battling the clear twilight sky near the sun and the distorting effect of Earth’s atmosphere” , said Sheppard to the press let loose. “DECam can cover large swaths of the sky to depths not achievable with smaller telescopes, allowing us to go deeper, cover more sky and explore the inner solar system in ways that have never been done before.”