The United Nations and planetary defense groups are monitoring asteroid 2024 YR4, which has a 1.3% chance of colliding with Earth on December 22, 2032. The European Space Agency (ESA) estimates a 99% probability of YR4 safely bypassing Earth but admits that a possible impact cannot be fully ruled out.
Dr. Robert Massey of the Royal Astronomical Society reassures the public that there is no immediate cause for concern. “No need to panic,” he said. “Historical trends show that initial impact estimates often disappear once calculations improve.”
Astronomers detected YR4 on December 27, 2024, estimating its size between 40m and 90m. An asteroid of this magnitude could generate an impact as powerful as a nuclear bomb, causing severe damage in populated regions. However, current data suggests it would likely land in the ocean or an uninhabited area if a collision occurred.
Since January, astronomers have been refining YR4’s size and orbital path. The asteroid currently rates at level 3 on the 10-point Torino Impact Hazard Scale, which indicates a close encounter requiring attention. A rating of 8, 9, or 10 confirms a significant collision threat, but YR4 is far from that level.
Astronomers remain optimistic that further observations will lower its impact risk, as seen with asteroid Apophis in 2004. Initially thought to pose a 2.7% chance of impact in 2029, improved data later eliminated that threat.
Asteroids larger than 50m with more than a 1% chance of impact trigger international safety protocols. The first step involves activating the International Asteroid Warning Network (IAWN) and the Space Mission Planning Advisory Group (SMPAG). These groups are chaired by NASA and ESA, respectively.
SMPAG is currently meeting to discuss YR4’s potential threat. They have decided it is too early for immediate intervention but will monitor the asteroid’s trajectory closely. Further meetings are scheduled for late April or early May to reassess any changes in risk.
If YR4’s impact probability remains above 1%, SMPAG will recommend precautionary measures to the UN. One possible strategy involves diverting the asteroid using a robotic spacecraft, as demonstrated by NASA’s successful Dart mission in 2022. That mission altered the path of a non-threatening asteroid, showcasing the effectiveness of early intervention.
Dr. Massey emphasized the importance of early detection: “Dart proved we have the capability to deflect an asteroid, but timing is key.”
Currently, YR4 is moving away from Earth in a near-straight line, complicating precise tracking of its orbit. As it fades from view in the coming months, astronomers will continue monitoring it with ground and space-based telescopes.
According to ESA, YR4 may become unobservable before astronomers can rule out any impact risk for 2032. If so, the asteroid will remain on ESA’s risk list until 2028, when it will be observable again for further evaluation.
