UN planetary defense organizations are keeping a close eye on asteroid 2024 YR4, which poses a tiny risk of impacting Earth on December 22, 2032. The European Space Agency (ESA) has stated that there is an almost 99% chance the asteroid will safely pass by Earth, but a potential collision cannot be entirely ruled out at this stage.
Currently, the probability of an impact is estimated at 1.3%. Despite this small chance, experts, including Dr. Robert Massey of the Royal Astronomical Society, are not sounding alarms. “There is no need for panic,” Dr. Massey remarked. “Historically, when these types of events are recalculated, the potential for impact usually disappears.” He emphasized the importance of monitoring such threats carefully, while ensuring astronomers are equipped with the necessary resources to track them.
The asteroid, first detected on December 27, 2024, is estimated to be between 40 meters and 90 meters in diameter. In the unlikely event of a collision, the asteroid would release the energy equivalent of a nuclear bomb, potentially causing severe damage, particularly if it struck a populated area. However, it is much more likely that the asteroid would land in the ocean or a remote region, as its trajectory is still too uncertain to predict a specific impact location.
Since January, astronomers have been using telescopes to refine the asteroid’s size and trajectory. As of now, asteroid 2024 YR4 is rated at level 3 on the Torino Impact Hazard Scale, which indicates a “close encounter that warrants attention from astronomers and the public.” A collision would only be considered certain if the rating rises to 8, 9, or 10.
Historically, the probability of impact has dropped to zero after further observations. A similar situation occurred in 2004, when asteroid Apophis was initially predicted to have a 2.7% chance of striking Earth in 2029, but further monitoring ruled out any risk.
In cases where an object larger than 50 meters has a greater than 1% chance of hitting Earth, precautionary measures are activated. These measures ensure that the threat, even if small, is closely observed and that necessary actions can be taken if needed. Two UN-endorsed asteroid defense organizations, the International Asteroid Warning Network (IAWN) and the Space Mission Planning Advisory Group (SMPAG), are responsible for this monitoring. The IAWN is chaired by NASA, and the SMPAG is led by the European Space Agency.
This week, the SMPAG is holding meetings to assess the situation. The group has already concluded that immediate action is not required but will continue to monitor the asteroid’s trajectory closely. A follow-up meeting will take place in late April or early May to discuss further steps, depending on the evolution of the threat. If the probability of impact remains above the 1% threshold, SMPAG will provide recommendations to the UN and may begin evaluating potential responses.
In the unlikely event that asteroid YR4 is on a collision course, one potential solution would be to divert its path using a robotic spacecraft, similar to NASA’s successful DART mission in 2022. The DART mission demonstrated that it is possible to alter an asteroid’s course if it is detected early enough.
At present, asteroid YR4 is moving away from Earth in nearly a straight line, making its orbit difficult to precisely predict before it returns toward our planet. Over the coming months, the asteroid will begin to fade from view, and monitoring will continue using both ground-based and space telescopes. If the asteroid becomes invisible before a conclusive assessment can be made, it will remain on ESA’s risk list until it becomes observable again in 2028.
As it stands, the risk of an impact remains incredibly small, but the global community continues to remain vigilant and prepared for any future developments.
