Moon Dust – rediscovered
Moon dust is in the news. The Lunar Atmosphere and Dust Environment Explorer (LADEE) mission currently in lunar orbitis about to begin the science phase of examining the thin lunar exosphere and looking for signs of dust fountains and the curious glow of lofted dust on the lunar horizon as reported by several Apollo astronauts.
It’s soft, sticky, scratchy stuff that has a tendency to cling to everything and was responsible for ruining several scientific experiments, causing them to overheat. A big challenge on each Apollo mission was to stop it getting it inside the lunar module. John Young (Apollo 16) thought it tasted “not half bad, ” Gene Cernan (Apollo 17) said it smelled like spent gunpowder and Jack Schmitt (Apollo 17) developed the first case of lunar moon dust “hay fever.”
Apollo missions 12, 14 and 15 left scientific experiments on the Moon (using solar cells) aimed at finding out how fast moon dust would accumulate. A build-up of moon dust blocked sunlight causing the voltage produced by the solar cells to drop. Shielded and unshielded tiny solar cells sent data back to Earth until 1977. NASA assumed the data had been lost until 40 years after the solar cells had been left on the Moon the lunar scientist who developed the experiment, Brian O’Brien, said he had backup copies and began to analyse the data.
The conclusion is that moon dust builds up faster than it should in a place with no atmosphere – just the thinnest of exospheres – at a rate of 1 millimetre every 1,000 years. Why? The strange dusty lunar exosphere holds the answer.
Over to LADEE.
The whole of the Moon
Using stunning Wide Angle Camera (WAC) images the LRO team created this timelapse movie of the rotating Moon. From Earth we don’t see the Moon rotate like this because the Earth’s gravity slowed the Moon down by constantly pulling against the rotation. Eventually, after millions of years, the Moon became tidally locked and now rotates about its axis in about the same time it takes to orbit the Earth so the same face of the Moon always points towards Earth.
Enjoy this spacecraft-eye view of the Moon.
APOD videos on You Tube
If you’ve ever wondered how many clicks you and your fellow Moon Zoo explorers have accumulated there is a way to find out. Click on the MoonometerTM link on the main Moon Zoo page to find not only the number of clicks (3,603,009 at the time of writing) but what those clicks look like in terms of more familiar things, like how many Australias (0.028), how many Disneylands (635,825) or how many Armillaria Ostoyae (24,290).
Keep checking back to see the numbers increase!
Massive thanks to everyone for each and every click. That’s over 3 and a half million clicks in the name of lunar science.