'City-Killer' Asteroid May Hit Moon, Hurl Deadly Debris Toward Earth

NASA scientists now believe that asteroid 2024 YR4, once thought to pose a slight threat to Earth, may instead collide with the Moon in the coming years. New calculations suggest a 4.3% chance of impact in 2031.

First detected on December 27, 2024, by the Asteroid Terrestrial-impact Last Alert System in Hawaii, YR4 passed close to Earth just two days earlier. It orbits the Sun every four years.

Recent observations in May 2025 from the James Webb Space Telescope estimate the asteroid's size between 174 and 220 feet (53-67 metres), roughly the height of a 10-storey building or the wingspan of a Boeing 747. Earlier estimates ranged from 131 to 295 feet.

Data from NASA's Centre for Near Earth Object Studies at the Jet Propulsion Laboratory indicate the likelihood of the asteroid hitting the Moon has steadily risen from 1.7% in February to 3.8% in April, and now to 4.3%.

If it does impact the Moon, it's expected to strike the near side, offering a rare chance for scientists to observe crater formation in real time. For now, YR4 is too distant to be tracked by telescopes. It will next approach Earth again in December 2028.

"While an Earth impact by 2024 YR4 on December 22, 2032 has now been ruled out, it continues to have a non-zero probability of impacting the Moon at this time," the researchers wrote in their preliminary report, which has not yet been peer-reviewed.

Asteroid 2024 YR4 is considered rare, once holding over a 1% impact probability-an extremely unusual threat level. NASA data suggests such an event would occur roughly once in 1,000 years. It's been compared to asteroid Apophis, which once ranked Level 4 on the Torino scale. Apophis will pass close to Earth in 2029, offering a rare visual encounter.