India, Aug. 2 -- A drifting SpaceX rocket stage is on course to accidentally collide with the Moon this week, creating a crater and sending a plume of dust and debris across the lunar surface. Scientists and sky watchers are preparing to observe the rare impact event and study what it reveals about space debris.

The rocket's upper stage, which helped launch two lunar landers more than a year ago, is expected to hit the Moon on Wednesday, according to a report by the Associated Press.

The collision was not intentional, but experts say the event could provide valuable data on how objects behave when they strike the lunar surface.

Space tracking expert Bill Gray has predicted that the rocket stage will crash into the Moon at a speed of ar...