In a milestone that has amazed amateur stargazers and scientists alike, a team at NASA working with the Curiosity Rover have discovered that water is abundant in soil on Mars. The Curiosity Rover detected the chemicals present in Martian soil by scooping small amounts, heating the samples, and analysing the gas that evaporates. NASA reported last week that there is about 2% by weight water in Martian soil, which means you can extract a litre of water per cubic foot. This follows the 2010 discovery of water in craters on the moon, by the Indian Space Research Organisation, suggesting that water in the Solar System may be more abundant than previously thought.
Once thought to be a cold, barren desert, these finding could boost the possibility of one day colonising Mars in a long-term and self-sustainable way. Exobiologists, who study the conditions that could make life in space possible, would also rejoice in the news. Water is a fundamental ingredient in the occurrence of life on Earth, so with more water, it is more likely that we may find extraterrestrial life in the solar system.
The discovery of water on Mars has only added to the list of possibly hospitable celestial bodies that we know of. Europa, Jupiter’s fourth largest moon, and only slightly smaller than the Earth’s moon, has long been considered a candidate for possibly harbouring life. It has an icy surface that is thought to conceal an ocean underneath, and its atmosphere is comprised mainly of oxygen. Life on Earth has two original energy sources, the sun (in a process harnessed by plants and cyanobacteria called photosynthesis) and ambient hydrogen-based chemicals bubbling up from volcanic smoke stacks (in a process harnessed by bacteria called chemosynthesis). Europa may support life of the second kind and with water in Martian soil, Mars may support life of the first kind.
The Curiosity Rover did not, however, find any methane – a waste product typically indicative of life. Mars also doesn’t have a very thick atmosphere, and it is almost all carbon dioxide. Astrobiologists grapple with the issue that extraterrestrial life may be present, but not in any discernibly obvious way. Life beyond Earth may operate with different chemicals powered by some other energy source on a time scale incomprehensible to us. The possibilities are overwhelming, but with water on Mars and on the moon, it could be closer to home. Arthur C. Clarke, futurist and writer of 2001: A Space Odyssey poetically surmised: “Two possibilities exist: either we are alone in the universe or we are not. Both are equally terrifying.”