Admit it, you probably think about soil very little? What about the soil on the moon? Well it’s a shame because, as I’ve come to realise in the last few days, moon soil is pretty nifty.
For one thing it would be a good place to keep your beers cool. If you could collect a bucket of it, your beer would keep cool for hours, as the lunar soil has very bad thermal conductivity. You could pour boiling water on the surface of the moon, and because of the soil the layers underneath would stay at frosty temperatures.
It’s also seen to levitate. This was noticed by the Apollo astronauts, who saw that when they kicked up the dusty soil, it took longer to settle than the lack of atmosphere and low gravity of the moon should allow. It also stuck to everything, coating and damaging equipment in a way that had not been anticipated.
We now think this is because the lunar soil gets electrostatically charge. On the side facing the sun, the rays of sunlight (which aren’t hindered by any atmosphere) knock electrons off the material in the soil, leaving it positivity charged and able to repel other soil particles.
Now, an Australian scientist thinks he may have a clue as to why the lunar soil has these strange properties. Marek Zbik, based at the Queensland University of Technology used tomographic (3D x-ray images) to closely examine the bubbles within small glass beads found on the moon.
Funded by the Australian Synchrotron, Zbik took samples loaned from the Russian space program to the National Synchrotron Radiation Research centre (NSRRC) in Taiwan. The samples were part of the very first material robotically returned from the Moon, from the Luna 16 mission. As these are extremely rare samples, it was important that the analysis didn’t damage them. The super benefit of the synchrotron beam in this case was that Zbik could image the inside of the bubbles within the glass without breaking them.
“We were really surprised at what we found,” Dr Zbik has noted “Instead of gas or vapour inside the bubbles, which we would expect to find in such bubbles on Earth, the lunar glass bubbles were filled with a highly porous network of alien-looking glassy particles that span the bubbles' interior.’
These particles, which are in the order of a billionth of a metre in size (nanometres), could explain some of the bizarre behaviour of the lunar soil. It’s because at this scale the ‘normal’ rules of physics don’t seem to apply. The forces that dominate our world, like gravity, have very little effect at this scale. Instead its tiny packets of electric charge that dominates, which can lead to some very strange behaviour.
It is thought that the nanomaterials are be being formed by the millions of tiny ‘micro’ meteorites that the moon gets pelted by on a daily basis. If, as Dr Zbik’s results indicate, nanomaterials are abundant in the lunar soil then there could be yet more bizarre things to be found in the lunar soil. Size, it would seem, really does matter.
Dr Zbik’s published article on this work is open access and can be read here.