Moon Storms

An old Apollo experiment is revealing something new and exciting about the Moon: dust storms that may threaten future astronauts

Every lunar morning, when the Sun first peeks over the dusty soil of the Moon after two weeks of frigid lunar night, a strange storm stirs the surface.

The next time you see the Moon, trace your finger along the terminator, the dividing line between lunar night and day. That's where the storm is. It's a long and skinny dust storm, stretching all the way from the north pole to the south pole, swirling across the surface, following the terminator as sunrise ceaselessly sweeps around the Moon.

The Apollo 17 rover wasn't the only thing kicking up dust on the Moon...

Never heard of it? Few have. But scientists are increasingly confident that the storm is real.

The evidence comes from an old Apollo experiment called LEAM, short for Lunar Ejecta and Meteorites. "Apollo 17 astronauts installed LEAM on the Moon in 1972," explains Timothy Stubbs of the Solar System Exploration Division at NASA's Goddard Space Flight Center. "It was designed to look for dust kicked up by small meteoroids hitting the Moon's surface."

Billions of years ago, meteoroids hit
the Moon almost constantly, pulverizing rocks and coating the lunar surface with their dusty debris. Indeed, this is the reason why the Moon is so dusty. Today these impacts happen less often, but they still occur.

Apollo-era scientists wanted to know, how much dust is ejected by daily impacts? And what are the properties of that dust? LEAM was to answer these questions using three sensors that could record the speed, energy, and direction of tiny particles: one each pointing up, east, and west.

The box in the foreground is the Lunar Ejecta and Meteorites Experiment (LEAM)

LEAM's three-decade-old data are so intriguing, they're now being reexamined by several independent groups of NASA and university scientists. Gary Olhoeft, professor of geophysics at the Colorado School of Mines in Golden, is one of them: