Over the Moon about water
One of the most important bits of advice you’ll ever hear when you drive into the outback is to take water, and plenty of it. Humans can survive for a few weeks without food, but without water, we’d perish pretty quickly.
Taking several large containers of fresh water on a short camping trip is one thing. But when travelling into space, every extra kilogram of weight adds up. It’s little wonder that astronomers are excited about a recent discovery of water on the Moon.
When the Apollo missions set down on its surface several decades ago, they found it to be pretty dry. The rocks they brought back weren’t very encouraging, either. It seemed that the Moon was a complete desert, without so much as an ice cube to put into a lunar lemonade. However, their tests did show plenty of oxygen amongst the chemicals they detected.
More recent missions, including NASA’s Cassini and India’s Chandrayaan-1, provided researchers with some tantalising hints that the Moon might not be quite as dry as first thought. By analysing the light bouncing off its south pole, astronomers discovered hydrogen was amongst the elements present. Better yet, it was stuck to oxygen – they could detect hydrogen-oxygen bonds and this meant it was either in the form of water (H2O) or the hydroxyl group (OH), which is found in many different compounds.
Now, the Deep Impact lunar probe has confirmed the presence of both water and the hydroxyl group. In deep craters on the Moon’s South Pole, where the sun rarely shines, water from comets has collected as ice. Reactions from the solar wind may also produce small amounts of water on the rest of the lunar surface.
Water is handy for drinking for astronauts who might one day live there, but we are starting to split water into its elements and recombining as one mechanism for storing solar or other energy for fuel cells, etc. The water on these planets might also be used in this way as a renewable energy source and even for launching spacecraft to other planets. Fortunately, Mars also seems to have a rather substantial supply of water ice. Recent meteorite strikes have revealed large shiny patches of it just under its surface.
Australians are all aware of how important fresh water is here on Earth. Finding sources of it on other moons and planets is not only fascinating, it could be extremely important as we continue to explore our universe.