In January, astronomers had some busy days as the recently discovered space rock became the most dangerous asteroid in ten years and then hid behind the moon for a week. Fortunately, further observations have found that this poses no danger to the Earth if it fluctuates next year.
The asteroid, known as 2022 AE1, was discovered on January 6 and is estimated to be about 70 m (230 ft) wide. The next day, an automated system called Asteroid Orbit Determination (AstOD), which is part of the ESA Coordination Center (NEOCC), was designated for potential impact on Earth in the future on July 4, 2023 – Independence Day. ).
This system then calculates where each object is on the Palermo scale, which assesses the potential danger of impact. This scale takes into account the probability of impact and the kinetic output of the object – in fact, how much damage it will cause, based on its size and speed. Zero on the Palermo scale indicates a background level of danger, so anything with a positive value requires immediate attention.
Fortunately, objects with positive values are rare, and even if they are, further observations have always ruled out exposure. The most famous example Apophiswhich currently holds the record for Palermo’s highest score of 1.1 for influence in 2029. It has since been discovered that Apophis is posing there is no risk to the Earth at least in the next century.
Objects with a score of less than -2 on the Palermo scale are those that can be safely ignored, as they have either a very low chance of impact on Earth, or are too small to cause harm if they did. But temperatures between -2 and 0 require careful monitoring – and a warning for asteroid 2022 AE1 recorded -1.5.
“At first I was surprised to hear about an asteroid with a rating of 1.50, because such a high Palermo scale is very rare,” said Luca Conversi, NEOCC manager. “However, I was not too concerned, as we receive such notifications – albeit at a lower level – several times a year. As usual in these cases, we activated our global network of telescopes to immediately get more observations, and soon it seemed that this asteroid was unlike any of the others we saw. “
Subsequent observations gave an increased risk of impact, and by January 11 the asteroid had a Palermo value of -0.66, making it the most dangerous asteroid since 2009. And as soon as the tension was highest, the Moon intervened, obscuring observations the following week.
Determining the chances of 2022 AE1 hitting Earth was extremely important. A strike in July 2023 would mean that it is too late for us to establish any diversionary actions, and the 70-meter diameter of the cliff is large enough to cause significant damage to the region on the line of fire. It is 3.5 times larger than the Chelyabinsk meteor, which affected thousands of people in the explosion over Russia in 2013. It is also larger than the Cosmic Stone, which is believed to have been responsible for the Tunguska event, which flattened 2,150 km2 (830 square miles) of forest in 1908.
Fortunately, on January 20, astronomers were able to find him again, and these observations narrowed his path to quickly rule out any chance of exposure next year. If in early July 2023 AE1 2022 passes by the Earth, it will not approach about 10 million km (6 million miles), which is more than 20 times the distance to the Moon.
It’s reassuring to know that there are so many eyes in the sky, so if it turns out that some asteroid is on a collision course, we may have enough warning to intervene. And NASA is already experimenting with ways reject such dangers.
Tense journey from “the most risky asteroid in ten years” to no threat
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