Feb 5, 2007
Scientists have discovered that the surface of the moon can accumulate a huge charge of static electricity - up to 4,500 V has been detected so far. The scientists, writing in Geophysics Research Letters number 34, say that their findings could have significant implications for those planning to colonise the rocky globe.
While astronauts would most likely be protected from any discharge by his or her suit, a spark from the surface could disrupt or even burn out electronic equipment.
The charge could also be responsible for levitating the ultra-fine moon dust. The dust is so fine it gets into absolutely everything, getting past vacuum seals and clogging equipment.
The scientists analysed data from the Lunar Prospector, which orbited the moon in 1998/1999. They were looking for traces of charge that would have built up as the solar wind slams into the lunar surface.
One of the authors of the research, Jasper Halekas of the University of California, told Nature.com that the 4,500V they detected is "more than enough to do some damage, if the electric field only extends over small distances".
If the charge is very diffuse, it might not cause a shock at all, he added.
A charge builds up on the lunar surface when it is hit by electrically charged particles. This is particularly intense when the moon passes through the Earth's magnetotail, and during solar storms.
Although the local field strength is not known, if the charge accumulates in sufficiently small areas, it could cause problems for colonising astronauts, particularly during dangerous solar activity.
With no atmosphere, the lunar surface would be a very dangerous place during either a solar storm or a sweep through the magnetotail.
The latter can be predicted and planned for, but astronauts would rely on their instruments, vulnerable to the effects of the static build up, to warn of a coming solar storm. This means instruments heading for the moon would need the same kind of spark-proof protections as satellites orbiting Earth. ®