When you buy through links on our articles, Future and its syndication partners may earn a commission.Credit: NOIRLab/NSF/AURA/R. ProctorThe James Webb Space Telescope has helped scientists determine that asteroid 2024 YR4, which previously had a 4.3% chance of crashing into our moon, will not impact our lunar companion at all. Instead, it will instead safely cruise past the moon at an altitude of 13,200 miles (21,200 kilometers).When asteroid 2024 YR4 was discovered on Dec. 27, 2024 by the NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS), it was for a short time the most dangerous asteroid ever discovered. With a diameter of about 197 feet (60 meters) there was originally a non-zero chance that it could impact Earth on Dec. 22, 2032. An asteroid of this size could destroy a city, or if it struck the ocean, produce a catastrophic tsunami that would endanger multiple coastal regions.AdvertisementAdvertisementHowever, it was quickly found that 2024 YR4 would miss the Earth — but it remained unclear whether it’d hit the moon instead. Specifically, there was a 4.3% chance that it could strike the moon on Dec .22, 2032 instead. The uncertainty was the result of 2024 YR4’s orbit around the sun not being known as precisely as needed in order to decide for sure whether it would hit the moon or miss it.A visualization of asteroid 2024 YR4 approaching our neck of the woods. | Credit: NOIRLab/NSF/AURA/R. ProctorAstronomers thought they would have to wait until 2028 to get the next chance to observe 2024 YR4 and refine its orbit before getting some clear answers, but researchers at the Johns Hopkins University Applied Physics Laboratory (JHUAPL) realized that there would be a chance for the James Webb Space Telescope (JWST) to observe 2024 YR4 between Feb. 18 and Feb. 26 this year.During that week, the asteroid was moving against a faint field of stars whose positions have been precisely measured by the European Space Agency’s Gaia mission. By tracking the object’s motion against those stars, the James Webb Space Telescope (JWST) w …
