0.28% chance of impact for the asteroid 2024 YR4, NASA reduces the risk as expected!
Impression of artist of an asteroid such as 2024 YR4. © ESA
As would be expected, the new trajectory calculations of the asteroid 2024 YR4, discovered last December, reduced its risk of terrestrial impact to 1 chance only in 360, or about 0.28 %. And it's completely logical, we will explain why. It is the CNEOS (Center for the Study of the Geocroisors), dependent on the NASA JPL, which made the announcement on his site yesterday (February 20, 2025), following measures made between February 19 and 20.
Admittedly, 2024 YR4 had seen its probabilities of falling on earth in 2032 were 3.1 % a few hours earlier. Many newspapers then titled in a worrying, even catastrophic tone, and nicknamed the celestial pebble “The killer of cities”. It was very badly knowing this type of situation … like We announced it to you a few days agoseeing this probability rising before falling almost zero was predictable.
2024 YR4 had triggered the alert by reaching 1% risk of impact
Planetary defense meeting in 2023 between NASA, the White House and the IAWN © NASA
There is a planetary defense protocol piloted by NASA and ESA, which mainly aims to better assess the risk of impact and, if necessary, the actions to be implemented to avoid it. On January 28, following exceeding the threshold fixed of 1 % risk of impact, NASA brought together the IAWN (International Asteroid Surveillance Network), which issued An alert the next day.
We then saw the impact probabilities go up regularly, up to the maximum of 3.1 %. It should be made in mind that such calculations are tainted with a lot of uncertainties, because astronomers do not have data prior to the discovery of the asteroid. They only have snapshots from which they must calculate possible trajectories. If we show you the photo of a pebble in the air, you can neither give his speed or direction, but the more images you have in different times, the more information you have on them.
After more than a month of observations with powerful telescopes, the risk fortunately fell below 1 %. After reaching the 3 threshold on Turin scalehere it is now fixed at 1, which remains an exceptional score, because few geocroisors are maintained above 0.
From now on, 2024 YR4 is quite far from the “lock hole”
Here is the probable trajectory of 2024 YR4 in December 2032: it will pass as close as possible to the earth around December 7 a few million kilometers from our planet. © NASA/JPL
A gravitational lock hole is a tiny region of space where the combined attraction forces can deflect an asteroid inevitably towards the earth. According to the latest measures, 2024 YR4 is far from it. Our surveillance system therefore works very well and this “teasing” asteroid will probably have been a very good training.
