Friday, April 24, 2009

Why Is Moon Dust Sticky?

Hum... I didn't even know this "problem" exists, i.e. I didn't realize that moon dust is sticky.

(See? Even an old goat like me learn new things all the time!)

It appears that a physicist in Australia may have an explanation why moon dust is sticky.

Now, a scientist who has been studying the problem off and on over four decades thinks he may have untangled the mystery of why that dust is so sticky. Brian O'Brien, an Australian physicist who worked on the Apollo program in the 1960s, said the sun's ultraviolet and X-ray radiation gives a positive charge to the dust, making it stick to surfaces such as spacesuits.
Over two years of painstaking research, O'Brien tracked the dust accumulating on two solar cells, one horizontal and one vertical, over the course of two lunar days. That may not sound like much time, but a lunar day equals nearly 30 days on Earth.

He found that little dust collected on the horizontal cell in the lunar morning, when the sun's rays were slanted, while more dust adhered to the vertical cell, which more directly faced the rising sun.

The weaker the sun's rays, he found, the weaker the electrostatic forces causing the dust particles to stick, until the dust fell off.

Some scientists believe that one of the greatest challenges for future lunar colonists will be keeping their lungs free of the particles, each thinner than a human hair but sharp as a razor.

So this isn't just something to tackle out of curiosity or for fun.



Karrasko said...

I didn't know either. It's really a challenge for the scientists.

Tometheus said...

I'm not exactly sure why this 'new discovery' is making the rounds so much lately. It has long been assumed that static is the reason for the dust adhesion. As an example: Why is Moondust So Clingy?"Many researchers believe that moondust has a severe case of static cling: it’s electrically charged. In the lunar daytime, intense ultraviolet (UV) light from the sun knocks electrons out of the powdery grit. Dust grains on the moon’s daylit surface thus become positively charged." (2005)

Tometheus said...

I think the 'newness' of the new research is not that static is the cause, but that the static may be worse if the astronauts are on the moon at 'high noon' than around 'sunrise'. (I think this article does a better job of expressing what the new idea is.)

Muhammad Fawaz said...

hiya. I stumbled across your blog and started reading through, i like it. but! i also hafta ask, how is lunar dust razor sharp? i'm not a pro but i'm interested and would love to know. thanks!

indiessance said...

Also, most space "dust particles are exposed to plasmas" or highly ionized gases.