The moon is safe from a “city-killer” asteroid named 2024 YR4, thanks to recent observations from the James Webb Space Telescope (JWST). This asteroid will pass by the moon in 2032, but it’s no longer a threat. Initially, there was a 4.3% chance it could hit the lunar surface. However, new data has reduced that risk to zero.
2024 YR4 will glide close to the moon—just 13,200 miles (21,200 kilometers) away. That’s actually closer than some satellites orbiting Earth, according to a NASA statement. While it will miss Earth by hundreds of thousands of miles, astronomers are relieved that it’s no longer a concern.
NASA credits the JWST’s advanced infrared instruments for making these precise observations. This was no small task; the asteroid had been hard to track since spring 2025. The latest images were described as “among the faintest ever” captured of an asteroid.
Discovered in late 2024 by the Asteroid Terrestrial-impact Last Alert System (ATLAS), 2024 YR4 measures about 174 to 220 feet (53 to 67 meters) long—similar in height to the Leaning Tower of Pisa. If it were to collide with Earth, it could release energy equivalent to 500 Hiroshima bombs, earning its “city-killer” nickname. At one point, scientists feared a collision risk of 3.1%, the highest ever recorded for an asteroid.
What if 2024 YR4 had struck the moon? It wouldn’t be its first hit, but it would have been a significant event. Some experts believed the explosion could have been visible from Earth, possibly resulting in debris showers that might lead to a new meteor shower.
Now that the threat is gone, 2024 YR4 remains a valuable object for study. NASA plans to observe it again in 2028, which will help improve our understanding and preparedness for future asteroid encounters.
This ongoing interest aligns with the growing focus on planetary defense as more asteroids are tracked. According to a recent NASA report, technology for spotting and tracking near-Earth objects has improved significantly, reducing the chances of being caught off guard by potential impacts.
In a world where space exploration is becoming a hot topic, the safety of our moon and Earth remains paramount, and projects like those involving the JWST are helping to pave the way for a more secure future.
