The recently discovered asteroid 2024 YR4 has caught astronomers' attention for an unexpected reason. While the risk of impact with Earth has been ruled out, a probability of collision with the Moon remains.
Latest observations reveal a 4.3% chance that this celestial object will strike our natural satellite on December 22, 2032. Although low, this probability remains significant enough to warrant increased monitoring. Scientists are waiting until 2028 to refine their predictions, when the asteroid will be observable again.
Close monitoring for an uncertain trajectory
Detected in late December 2024, 2024 YR4 was quickly classified as a potentially hazardous asteroid. Its estimated diameter between 53 and 67 meters (174 to 220 feet) makes it a serious threat in case of impact. Initially, calculations suggested an Earth impact risk peaking at 3.1%, before being revised downward.
Thanks to the James Webb Space Telescope, astronomers have been able to refine their orbital modeling. This data ruled out any danger to Earth but also revealed a slight increase in the chances of a lunar impact. The asteroid remains too distant for new observations before 2028.
If a collision were to occur, it would create a crater about one kilometer (0.6 miles) in diameter. The energy released would be equivalent to 6.5 million tons of TNT, a rare event but not without consequences.
The implications of a potential impact
A collision with the Moon could eject millions of kilograms of debris into space. Some of this material could be drawn by Earth's gravity, forming a meteor shower. These fragments, although small, would pose a risk to low-orbiting satellites.
Space agencies are already considering missions to deflect the asteroid if necessary. NASA's DART mission demonstrated the feasibility of such a maneuver in 2022. However, late intervention would complicate the operation, hence the importance of early detection.
To improve monitoring, ESA plans to launch the NEOMIR satellite in the 2030s. This infrared observatory will detect asteroids approaching from the Sun's direction, a blind spot for current telescopes.
Article author: Cédric DEPOND