The closest thing I know to fairy dust is moon dust, and yesterday I got to hold a glass jar containing 0.3 grams of lunar soil retrieved by Apollo 17 astronauts and returned to Earth in 1972. It made me giddy. The material was very dark grey, almost black. While not a powder, the dust had been sieved so the material was very fine-grained.
“There’s a hair in there,” said Kate Greene, a freelance science writer out of San Francisco when the jar passed to her hands. All heads turned. Apparently a tiny electrostatic charge caused the dust particles to line up, creating the first lunar “hair”. As each held the jar in turn and studied its contents with wide eyes, our host, Dr. Mihaly Horanyi, principal investigator for the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS), kept an eye on it to make sure nothing untoward happened to the sample. He half-joked he’d be thrown in jail if even a molecule of the dust somehow got away.
We were incredibly grateful he shared such a precious thing. It was one of many highlights at the conference I’m attending at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado in Boulder this weekend.
Dr. Horanyi researches lunar dust liberated by the impact of tiny meteorites called micrometeoroids. These burn up in Earth’s atmosphere, but on the airless moon, 5 tons worth a day strike the surface unimpeded, grinding away at the lunar rocks like a dog gnawing a bone.
Because of its long history of impact from the earliest times to this day, the moon’s soil is a jumble of shattered rocks, melted bits of rock and billions of tiny, sharp-edge dust particles that resemble finely shattered glass. Horanyi has done experiments – one involving “kicking” a pizza pan coated with dust in a controlled setting – to show that solar ultraviolet light bathing the moon’s surface causes dust particles to levitate electrostatically.
If you’ve ever had plastic wrap or styrofoam peanuts jump into your hands, you’re familiar with electrostatic forces. Apollo astronauts reported glowing dust clouds backlit by the rising (or setting) sun near the horizon during their forays across the lunar landscape. Horanyi recreated these on a smaller scale.
Horanyi is the principal investigator for the Lunar Dust Experiment (LDEX) that will be flown to the moon in 2013 aboard the Lunar Atmosphere and Dust Environment Explorer (LADEE). He hopes to examine dust shot out by meteoroid impacts as well as get a better handle on what causes those peculiar dust clouds seen by the astronauts and photographed by several spacecraft. You can learn more about levitating lunar dust in this earlier blog.
I could go on and on but have to get moving to attend the last lectures this morning. I will share more tomorrow. One thing I can tell you – I have a greater respect and appreciation for dust thanks to Mihaly’s insights. Seeing the lunar variety up close was levitation for the soul.