Could an Asteroid Impact Knock the Moon into the Earth?
Collision Course It would take a moon-sized object to move the moon. NASA/JPL-Caltech "If an asteroid hits the moon, it will just get another crater," says Gareth Wynn-Williams, an astronomer at the University of Hawaii. It would take a moon-size object to move the moon, says Clark Chapman, a planetary scientist at the Southwest Research Institute, and most likely the moon wouldn't survive. Hitting it with a much larger, denser object would be like whacking an egg with a golf club. But let's say that the moon and the thing hitting it will react like solid billiard balls. None of the known asteroids larger than 60 miles in diameter orbit anywhere near the moon. OK, how about if the largest known asteroid, Ceres-which at 600 miles across is roughly the size of California and Nevada combined-did manage to slip out of its place in the asteroid belt and set out...