Funny you should ask, we actually have a Lunar module studying this question right now: http://en.wikipedia.org/wiki/Lunar_Atmosphere_and_Dust_Environment_Expl

Funny you should ask, we actually have a Lunar module studying this question right now: http://en.wikipedia.org/wiki/Lunar_Atmosphere_and_Dust_Environment_Explorer http://en.wikipedia.org/wiki/Lunar_Atmosphere_and_Dust_Envir... The NASA dust lab slides claimed it levitated right after noting that the dust particles had "charges approaching 10^4" (no units or context provided). I assumed that was related. In hindsight, maybe it isn't? Apparently, and I'm just learning all this right now, some scientists argue the dust is primarily ejected from the surface during meteor events. The earliest observations of "levitating" dust were from astronauts who noticed rays of light during/after the lunar sunset, suggesting the sunlight was bouncing off of something in the lunar "atmosphere."