An international team of astronomers announced Monday the discovery of a large asteroid whose orbit intersects Earth’s, leaving a slim chance of a catastrophic collision far in the future.
Named 2022 AP7, the 1.5-kilometer-wide asteroid was discovered in an area notoriously difficult to see due to the sun’s glare.
It was found along with two other near-Earth asteroids using a high-tech instrument on the Victor M. Blanco Telescope in Chile, which was originally developed to study dark matter.
“2022 AP7 will cross Earth’s orbit, making it a potentially dangerous asteroid, but it doesn’t have an orbit currently or in the future that will cause it to collide with Earth,” said astronomer Scott Sheppard of the Carnegie Institute of Science.
The potential threat comes from the fact that, like any object orbiting the Earth, its orbit will be slowly altered due to numerous gravitational forces, particularly from planets. Forecasts are therefore difficult in the very long term.
The newly discovered asteroid is “the largest object potentially dangerous for Earth to be discovered in the past eight years,” said NOIRLab, a US-funded research group that operates multiple observatories.
2022 AP7 will take five years to orbit the sun under its current orbit, which remains several million kilometers away at its closest point to Earth.
The risk is therefore very small, but in the event of a collision, an asteroid of that size would “have a devastating impact on life as we know it,” Sheppard said. He explained that dust launched into the air would have a major cooling effect and cause an “extinction event not seen on Earth in millions of years”.
His team’s results have been published in the scientific journal The Astronomical Journal. The other two asteroids pose no risk to Earth, but one is the closest asteroid ever found to the sun.
About 30,000 asteroids of all shapes and sizes — including more than 850 larger than a kilometer across — have been cataloged near Earth, earning them the label “Near Earth Objects” (NEOs). None of them threaten the Earth for the next 100 years.
According to Sheppard, there are “probably another 20 to 50 large NEOs to be found,” but most are in orbits that place them in the glare of the sun.
In preparation for a future discovery of a more threatening object, NASA conducted a test mission in late September in which a spacecraft collided with an asteroid, demonstrating that it was possible to change its orbit.