NASA has released a major update on asteroid 2024 YR4, once feared to be a potential “city killer.” The space rock, estimated to be about 200 feet wide, raised concern after it was discovered in December 2024, when early calculations suggested a small chance it could collide with Earth in 2032.
Although the possibility of an Earth impact was later ruled out, astronomers continued tracking the asteroid because it still had a chance of striking the Moon during a close approach in December 2032. At one point, NASA estimated about a 4.3% probability of a lunar impact.
New data collected by the James Webb Space Telescope in February 2026 has now allowed scientists to refine the asteroid’s trajectory. The updated calculations show that 2024 YR4 will not hit the Moon and will instead pass safely at a distance of roughly 13,200 miles.
Before the new observations ruled out a collision, some researchers had even explored extreme defense options, including the possibility of using a nuclear device to alter the asteroid’s trajectory if it ever posed a serious threat.