Asteroid 2024 YR4 will miss Earth but might strike the moon – what happens if it does?

Time of India

2 days ago

An asteroid once thought to be heading for Earth is now out of sight, but not out of mind. Named 2024 YR4, this 200-foot-wide space rock could strike the moon in late 2032. And scientists are paying close attention to what that could mean for both space missions and life on Earth.
From 'City Killer' to lunar threat
Discovered in late 2024 by the ATLAS telescope in Chile, asteroid 2024 YR4 raised alarms. At one point, it had a 3.1% chance of hitting Earth by December 22, 2032—the highest risk ever recorded for an asteroid, according to
NASA
.
That changed after new measurements were taken using ground-based telescopes and the James Webb Space Telescope (JWST). These helped track the asteroid more precisely, improving its predicted orbit by 20%.
The good news: Earth is now safe. But the not-so-good news? The moon might not be.
What happens if it hits?
A moon impact would not threaten life on Earth directly. But the consequences could still be significant. Scientists say the strike could form a 1-kilometer-wide crater on the moon and send up to 100 million kilograms of dust and rock into space. The size of such rocks is not an issue, as the atmosphere will protect Earth from that.
However, the debris could harm satellites or even astronauts on the moon. Fine lunar dust, traveling faster than a bullet, might reach Earth within days or months and trigger a bright
meteor shower
.
Tracking, planning, and what comes next
Scientists are already preparing to observe YR4 again when it comes back into view around 2028. A proposal by MIT's Julien de Wit and Johns Hopkins' Andy Rivkin to use Webb for an early look in 2026 was recently approved.
'This newly approved program will buy decision makers two extra years to prepare, though most likely to relax, as there is an 80% chance of ruling out impact,' said de Wit.
Rivkin, who led the DART mission that successfully deflected a different asteroid in 2022, says YR4 presents a different kind of question.
Would we ever try to deflect something headed for the moon? 'We realize that an impact to the moon could be consequential, so what would we do?' said de Wit.
As more infrastructure, missions, and astronauts are expected on the moon in the coming decades, astronomers believe events like YR4 must be taken seriously.
'If this really is a thing that we only have to worry about every 5,000 years or something, then maybe that's less pressing,' Rivkin said. 'But even just asking what would we do if we did see something that was going to hit the moon is at least something that we can now start thinking about.'