Huge ‘planet killer’ asteroid discovered – and it’s heading our way

Astronomers say they have discovered the largest planet killer-sized asteroid in eight years, and that the huge space rock will cross Earth's orbit.

The asteroid, named 2022 AP7, was reported by researchers looking for space rocks within the orbits of Earth and Venus.

Writing in the Astronomical Journal, lead study author Scott Sheppard and colleagues at the Carnegie Institution for Science in Washington say they have found three "rather large" asteroids, one of which - 2022 AP7 - crosses the Earth's orbit, making it a potentially hazardous asteroid (PHA).

With a diameter of about 1.1km to 2.3km, the team say 2022 AP7 is the largest PHA discovered since 2014 and probably in the top 5% of the largest ever found.

"Any asteroid over 1km in size is considered a planet killer," said Sheppard, adding that should such an object strike Earth, the impact would be devastating to life as we know it, with dust and pollutants kicked up into the atmosphere, where they would linger for years.

"The Earth's surface would likely cool significantly from sunlight not getting to the planet. It would be a mass extinction event like hasn't been seen on Earth in millions of years," he said.

While the finding of 2022 AP7 may bring to mind visions of the asteroid Armageddon depicted in the film Don't Look Up, the study also offers reassurance.