The newly discovered ‘planet killer’ asteroid could one day threaten Earth

Astronomers have spotted a ‘planet killer’ asteroid crossing Earth’s orbit and could be slowly getting closer and closer to us centuries from now.

With a diameter of about 1.1 km to 2.3 km, the asteroid, called 2022 AP7, is the largest potentially dangerous object to Earth discovered in the past eight years, the team said.

It is also likely to be in the top 5 percent of the largest potentially hazardous asteroids (PHAs) known.

The asteroid was spotted by researchers using the Dark Energy Camera in Chile to search for objects in the orbits of Earth and Venus. They described their findings in an article in The Astronomical Journal published in September.

“Our twilight survey scans the region within the orbits of Earth and Venus for asteroids,” said lead author Scott Sheppard, an astronomer at the Carnegie Institution for Science’s Earth and Planetary Laboratory.

“So far we have found two large near-Earth asteroids around 1 kilometer in diameter, a size we call planet killers,” he said. in a statement.

In addition to 2022 AP7, the team also spotted two other near-Earth asteroids, called 2021 LJ4 and 2021 PH27, which have orbits that stay safely completely inside Earth’s orbit and should never come into its path.

Planet killer ‘has no chance of hitting Earth right now’

The term “planet killer” may sound scary, but as far as 2022 AP7 is concerned, it will remain “too far” from Earth for now, according to Sheppard.

“It has no chance of hitting Earth right now,” he told Euronews Next in an email.

As things stand, 2022 AP7 crosses Earth’s orbit. That makes it a potentially dangerous asteroid, he said.

However, the transit occurs at a time when the Earth is on the other side of the sun, he explained, adding that this configuration will continue for the foreseeable future.

“Slowly, over time, the asteroid will begin to cross Earth’s orbit closer to where Earth is, but that will be centuries into the future, and we don’t know 2022 AP7’s orbit precisely enough to say much about its dangers centuries ago now,” he said.

“But for now, 2022 AP7 will stay too far from Earth.”

“It would be a mass extinction event”

If an asteroid 1 km or larger were to hit Earth, it would have a devastating impact on life as we know it, Sheppard said.

The dust and pollutants thrown into the atmosphere will remain there for years, likely meaning that the Earth’s surface will be significantly cooled by sunlight that does not reach the planet, he said.

“It would be a mass extinction event not seen on Earth for millions of years.”

The question of how to defend Earth from possible collisions of space objects recently made headlines when NASA confirmed that the spacecraft that crashed into an asteroid in September had managed to nudge the object out of its natural orbit.

The Double Asteroid Redirection Test (DART) mission was the first test of a planetary defense system designed to prevent a potential meteorite collision with Earth, and marked the first time humanity altered the motion of a physical body in space.

Asteroids hiding in the glare of the sun

The three newly announced asteroids are part of an elusive population lurking within the orbits of Earth and Venus, the research team said. It’s a notoriously challenging region for observations, they said, because asteroid hunters must contend with the sun’s glare.

But astronomers were able to counter this by conducting surveys during two 10-minute windows at night.

“There are probably only a few [near-Earth asteroids] with similar sizes to be found, and these undiscovered large asteroids probably have orbits that keep them inside the orbits of Earth and Venus most of the time,” Shepard said.

“Only about 25 asteroids with orbits completely inside the Earth’s orbit have been discovered to date because of the difficulty of observing near the sun’s glare.”

Sheppard said he and his team weren’t surprised by their findings, “since we know that some of these planet-killing asteroids are still out there that haven’t been discovered yet.”

In fact, they expect to find a few more killer planets or larger near-Earth objects (NEOs) within the next couple of years.

“To date, we believe there are about 1,000 NEOs larger than 1 km in size,” he said, adding that researchers had discovered about 95 percent of them in the past decade.