Before 2024 YR4 faded beyond the reach of Earth-based telescopes, Webb managed one more look. That last measurement improved astronomers’ knowledge of the asteroid’s predicted 2032 position by nearly 20%—and placed a slightly larger slice of its possible paths across the Moon.
NASA now gives YR4 a 4.3% chance of striking the Moon on December 22, 2032, up from 3.8%. That is close to 1 chance in 23. A miss is still overwhelmingly more likely, but 4.3% is substantial enough to make this one of the most intriguing celestial appointments on the calendar.
The number rose because the map became sharper, not because YR4 made a turn. If a lunar impact occurred, NASA says it would not alter the Moon’s orbit. It could, however, offer scientists something almost unheard of: a sizable natural impact with a date attached years in advance. For now the asteroid is disappearing into the dark, leaving researchers with a better route, a stubborn pocket of uncertainty, and seven years to think about what we might witness.