James Webb Telescope Confirms Asteroid 2024 YR4 Will Not Impact Moon
Recent observations from the James Webb Space Telescope (JWST) have definitively ruled out a potential impact between asteroid 2024 YR4 and the Moon in 2032. While initial calculations suggested a small probability of collision, new data acquired in February 2026, using the Near-Infrared Camera (NIRCam) instrument, has allowed scientists to precisely refine the asteroid’s trajectory.
Asteroid 2024 YR4: A “City Killer” Initially on the Radar
Asteroid 2024 YR4 was first discovered on December 27, 2024, by the ATLAS (Asteroid Terrestrial-impact Last Alert System) telescope in Chile. Classified as a near-Earth asteroid – meaning its orbit brings it within 45 million kilometers of Earth – the asteroid initially raised concerns due to its estimated size of 50-70 meters in diameter. Objects of this size are sometimes referred to as “city killers” due to their potential to cause significant regional damage if they were to impact Earth.
JWST’s Crucial Role in Trajectory Refinement
Even though early assessments indicated no threat to Earth, a potential lunar impact in December 2032 remained a possibility, with calculations suggesting a probability of up to four percent. The JWST’s infrared observations, taken on February 18 and 26, 2026, proved critical in resolving this uncertainty. By accurately measuring the asteroid’s position relative to background stars, astronomers were able to significantly improve the precision of its orbital calculations.
The refined calculations now confirm that asteroid 2024 YR4 will pass safely by the Moon in 2032, at a distance of more than 20,000 kilometers. It will also pass Earth at a greater distance of 278,000 kilometers.
Future Flybys and Continued Monitoring
Another significant event will occur on December 17, 2028, when the asteroid will make a relatively close approach to Earth, passing within approximately eight million kilometers – more than twenty times the distance between the Earth and the Moon. While this flyby is not expected to significantly alter the asteroid’s orbit, it will provide astronomers with a valuable opportunity for further observation and refinement of its trajectory.
Studies published in the Journal of the Astronautical Sciences indicate that the 2028 Earth flyby will only cause a small change in the asteroid’s orbit. However, continued monitoring is essential, as even minor deviations can accumulate over time, particularly during the closer approach in 2032 when the asteroid will be influenced by both Earth and the Moon’s gravity.
Planetary Defense in Action
The story of asteroid 2024 YR4 highlights the effectiveness of current planetary defense strategies. Automated sky surveys, combined with a global network of observatories and powerful space telescopes like the James Webb Space Telescope, enable scientists to identify, track and assess the potential risks posed by near-Earth objects. This collaborative approach, leveraging both ground-based and space-based assets, is crucial for protecting our planet from potential asteroid impacts.
As NASA explains, the JWST is a premier observatory studying every phase of the Universe’s history, and its capabilities extend to tracking and characterizing near-Earth objects.