Astronomers exploiting low light at the end of the day discovered three near-Earth asteroids, or NEAs, one of which was nearly a mile (1.5 kilometres) wide and lurking in the blinding light of our own sun.
While these newly discovered asteroids are large enough to be disastrous if they collide with a planet, there are currently no predicted close approaches between any of them and Earth in the near future.
The space rocks were discovered during twilight observations made over the past two years with the Dark Energy Camera at NOIRLab’s Cerro Tololo Inter-American Observatory in Chile. The trio is led by 2022 AP7, a spacecraft roughly the size of the US Pentagon with an orbit that may one day put it in Earth’s path.
According to a statement released on Monday by Scott S. Sheppard from the Carnegie Institution for Science, “our twilight scan is scouring the space within the orbits of Earth and Venus for asteroids.” We have so far discovered two planet-killing-sized near-Earth asteroids that are around a kilometre across.
Sheppard is also the lead author of a paper that recounts the discovery of the asteroids 2021 LJ4 and 2021 PH27, which are each the size of the US Capitol and Golden Gate Bridge, as well as 2022 AP7, which was published in the Astronomical Journal in September. The latter two, in contrast to the largest of the three, are not thought to be potentially dangerous because their orbits keep them securely out of the way of our planet.
Over the years, astronomers have found and catalogued thousands of near-Earth asteroids, but there are still some areas where humanity is blind, particularly with regard to asteroids that are visible from Earth and travel very close to the sun. Astronomers were surprised when a meteor from an unidentified asteroid emerged from behind the sun and abruptly detonated over Russia in 2013.
Therefore, the discovery of these asteroids is a positive step for those interested in planetary protection. In addition to being the biggest possibly dangerous asteroid found in the previous eight years, 2021 PH27 is also the asteroid that is known to be closest to the sun.
