28 July 2025
The asteroid known as 2024 YR4 is out of sight yet still very much on scientists’ minds.
The building-sized object, which initially appeared to be on a potential collision course with Earth, is currently zooming beyond the reach of telescopes on its orbit around the sun. But as scientists wait for it to reappear, its revised trajectory is now drawing attention to another possible target: the moon.
Discovered at the end of 2024, the space rock looked at first as if it might hit our planet by December 22, 2032. The chance of that impact changed with every new observation, peaking at 3.1% in February — odds that made it the riskiest asteroid ever observed.
That data shows that even with Earth avoiding direct impact, YR4 could still pose a threat in late 2032 by slamming into the moon.
Initial calculations suggest the impact has the largest chance of occurring on the near side of the moon — the side we can see from Earth.
“YR4 is so faint and small we were able to measure its position with JWST longer than we were able to do it from the ground,” said Rivkin, who has been leading the Webb study of YR4. “And that lets us calculate a much more precise orbit for it, so we now have a much better idea of where it will be and won’t be.”
The collision could create a bright flash that would be visible with the naked eye for several seconds, according to Wiegert, lead author of a recent paper submitted to the American Astronomical Society journals analyzing the potential lunar impact.
The collision could create an impact crater on the moon estimated at 1 kilometer wide (0.6 miles wide), Wiegert said — about the size of Meteor Crater in Arizona, Rivkin added. It would be the largest impact on the moon in 5,000 years and could release up to 100 million kilograms (220 million pounds) of lunar rocks and dust, according to the modeling in Wiegert’s study.
Even pieces of debris that are just tens of centimeters in size could present a hazard for any astronauts who may be present on the moon, or any structures they have built for research and habitation, Wiegert said. The moon has no atmosphere, so the debris from the event could be widespread on the lunar surface, he added.
On average, the moon is 238,855 miles (384,400 kilometers) away from Earth, according to NASA.
Source:CNN
