Huge ‘planet killer’ asteroid discovered – and
it’s heading our way
With a diameter of 1 to 2km, space rock named 2022 AP7
crosses our orbit but has ‘no chance’ of hitting Earth
Nicola
Davis Science correspondent
@NicolaKSDavis
Tue 1 Nov
2022 19.05 GMT
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.
“It has no
chance to hit the Earth, currently,” said Sheppard, noting that at present 2022
AP7 crosses the Earth’s orbit when the Earth is on the other side of the sun.
Illustration
of the Chicxulub asteroid hitting Earth.
Sheppard
added that slowly, over time, the asteroid will start to cross Earth’s orbit
closer to where our planet is. But, he said, “this will be centuries into the
future and we do not know the orbit of 2022 AP7 precise enough to say much
about its dangers centuries from now.”
Sheppard
said the team expect to find “a few more” planet-killer near-earth objects 1km
in size or larger in the next year or two through their survey work, which uses
the Blanco four-metre telescope in Chile.
Jay Tate,
the director of the National Near Earth Objects Information Centre in mid
Wales, told the Guardian he was not losing sleep over 2022 AP7, adding that the
Earth was actually a very small target. “At the moment, anyway, the impact
probability is fairly low. I wouldn’t say negligible, but fairly low.”
The last
complete image of the Dimorphos asteroid transmitted from the Dart probe before
it successfully crashed into it on Tuesday
In
September, Nasa launched its Dart mission, ploughing a spacecraft into an
asteroid in an attempt to deflect the latter from its orbit. The mission was an
attempt to test technology that could eventually be used to tackle space rocks
that pose a threat to Earth. Last month, researchers confirmed Dart had been a
success.
Tate said
an approach like Dart might not be suitable for 2022 AP7, given the size of the
asteroid, but there were other possible methods.
“Having
said that, we’ve got bucketloads of time,” he said, adding it might be possible
to use multiple Dart-like impacts to shift the asteroid’s path a little at a
time.
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