Water found on the moon
Dr Chris Welch, a space expert based at Kingston University London, has provided the following question and answer briefing about the recent story that more water than previously thought has been found on the moon.
* What is so important about finding more water on the moon? Firstly, because it could make living on the moon much easier in the future. Secondly, because scientists thought they knew what the surface of the moon was like and these results show that they didn’t – or at least not completely. * What are the implications for human exploration? Water is very heavy and having to launch it into space is difficult. If there is water on the moon – in whatever form – then we have a potential reservoir that could be used to drink, to make into hydrogen and oxygen which can be used as rocket propellant. The oxygen could also be used to breathe. * Where does the water come from? The current thinking is that particles in the solar wind (which is emitted by and streams away from the sun continuously) strike the soil on the surface of the moon (which has no magnetic field or atmosphere to protect it) and stimulate chemical reactions in which oxygen atoms in the soil combine with hydrogen nuclei in solar wind to form water (H2O) and hydroxyl (HO) molecules. * Is it similar to water on Earth? (same minerals, etc) The water is thought to exist as a very fine film covering the particles of the lunar soil, or as groups of molecules, not as a liquid. The minerals on the moon are very similar to those on Earth, eg. ilmentite. * Can you drink it? Not in its current form, but if extracted, yes, certainly. It has been suggested that one cubic metre of soil would provide one litre of water. * How much is there? Earlier estimates suggest that there could be more than 300 million tonnes of water ice (see below) on the moon. These results suggest that it could be even more. * In what forms does it take? (Underground, river, etc) On the main lunar surface as described above – as slightly ‘damp’ soil and rocks. These are still much dryer than any on Earth, though. At the poles of the moon, it is thought that water ice may exist in craters that have been in shadow for millions of year and which act as ‘cold traps’ for water vapour that might arrive either from cometary impacts or – now – from the rest of the surface. * Does this mean there could be/once was a sign of life on the moon? No. * What further research now needs to be done? More detailed science missions – preferably landers to analyse the soil in space. On October 9 NASA LCROSS spacecraft will carry out two impacts on polar craters to see if it can throw up evidence of water ice.
( Dr Welch is the winner of the 2009 Sir Arthur Clarke Award for Achievement in Space Education )