UN planetary defence organisations are closely monitoring an asteroid that has a tiny risk of hitting the Earth.
The European Space Agency (ESA) has stated that the asteroid, named 2024 YR4, has an almost 99% chance of safely passing Earth on 22 December 2032. However, there is still a small possibility of impact that “cannot yet be entirely ruled out”.
The current estimated probability of the asteroid impacting Earth on the given date is 1.3%.
Dr. Robert Massey of the Royal Astronomical Society has stated that he is not alarmed about the situation and believes that historically these types of events tend to dissipate as calculations are refined.
Astronomers are actively tracking the asteroid’s size and trajectory using telescopes to provide more accurate information. As of now, YR4 is rated at level 3 on the Torino Impact Hazard Scale, indicating a close encounter that requires attention.
When initial calculations show a small probability of an asteroid impacting Earth, further observations often reduce that probability to zero. This was exemplified in 2004 with the asteroid Apophis.
Objects larger than 50m with a higher than 1% chance of impact trigger precautionary measures to ensure close monitoring and necessary actions to mitigate the threat.
In the unlikely event of YR4 posing a threat, options include diverting it with a robotic spacecraft, a method successfully tested with Nasa’s Dart mission in 2022.
ESA has acknowledged the possibility that YR4 might fade from view before ruling out any impact chance in 2032. In such a scenario, the asteroid will remain on ESA’s risk list until observable again in 2028.