After new observations moved Earth outside YR4’s possible 2032 paths, the Moon remained inside the uncertainty region. The estimated lunar-impact chance eventually reached about 4.3%—a genuine result from the available data and a compelling reason to point Webb at the fading asteroid again.
Those Webb observations tightened the route and revealed a flyby about 13,200 miles from the lunar surface. That is closer than the distance between New York and Sydney, with a little room to spare.
The changing probability records an extraordinary improvement in precision: astronomers went from a corridor wide enough to cross the Moon to a predicted passage they can describe in thousands of miles. The close approach now offers a chance to watch a 60-meter asteroid move through the lunar neighborhood in real time.