Something else for lunar colonists to worry about
The Sky Is Falling
NASA Science News - Huntsville AL (SPX) Jun 05, 2006 Up on the Moon, the sky is falling. "Every day, more than a metric ton of meteoroids hits the Moon," says Bill Cooke of the Marshall Space Flight Center's Meteoroid Environment Office. They literally fall out of the sky, in all shapes and sizes, from specks of comet dust to full-blown asteroids, traveling up to a hundred thousand mph.
http://www.moondaily.com/reports/The_Sky_Is_Falling.html