The new study, published in the journal Icarus, puts on the table the striking case of 2019 OK , an asteroid about 100 meters in diameter (the size of a football field) that passed just 70,000 kilometers from Earth without any of the telescopes will detect it up to 24 hours before its closest approach to our planet.
How was it possible not to detect such a large asteroid?
NASA and other space agencies and institutions around the world have created a vast network of telescopes and other monitoring systems to detect asteroids around space, specifically those that are approaching the planet, which are known as Near-Earth Objects (NEOs) . Most of these NEOs are asteroids, and the very close ones with a diameter of at least 140 meters can often be declared potentially dangerous.
A team of scientists led by the University of Hawaii at Manoa have found that some asteroids can “sneak up” on Earth thanks to a quirk in Earth’s rotation that makes them appear to be not moving and therefore makes it difficult to detect by telescopes. As if they were in stationary orbit and, evidencing, a blind spot in some early warning systems.
A gap in detection
Asteroids in this blind spot will appear stationary in the sky even as they approach Earth, making it more difficult for both NASA and other space agencies to track the movement of those objects.
It is a problem that was revealed with the case of 2019 OK.
The space rock was the first object of this size to come this close to our planet since 1908, but it was only detected 24 hours before its closest approach . The reason was that its low-speed motion across the night sky was counteracted by the Earth’s spin , so it looked like a stationary rock, and therefore potentially dangerous asteroid detection software was not activated.
According to their calculations, this finding means that half of these asteroids could be difficult to detect, and the computerized telescopes need an urgent update to take this effect into account. They need to be able to identify these slow-moving objects so we can be better prepared.
Countermeasures
The danger of an asteroid on a collision course with Earth is well documented in science fiction movies, but it could become a real threat in the future. Although NASA estimates that our planet will be free of asteroid impacts for the next century, there are a number of initiatives to deal with this possible threat. Without going any further, NASA’s DART mission is the world’s first planetary defense test mission, which will carry out a kinetic impact on the asteroid Dimorphos on September 26, 2022 to slightly change its orbit in space. This anti-asteroid system is intended to be an effective weapon to stop future impacts.
Referencia: Richard Wainscoat, Robert Weryk, Steven Chesley, Peter Vereš, Marco Micheli,
Regions of slow apparent motion of close approaching asteroids: The case of 2019 OK,
Icarus, Volume 373, 2022, 114735, ISSN 0019-1035,
DOI: https://doi.org/10.1016/j.icarus.2021.114735.
(https://www.sciencedirect.com/science/article/pii/S0019103521003894)
Keywords: Near-Earth Object; Earth impact; Asteroids
