So you’re into sci fi? But what about sci fact? Sometimes fact is stranger than fiction…
Each month our very own Voyager Science Queen* will bring you interesting, quirky and downright bizarre tasty morsels from the world of science. And its all completely, totally, 100% true!
Curiosity has its own reason for existing.
This past July and August was a very exciting time for the scientific community, with the discovery of the Higgs Boson particle and a photograph of an atom (see last month’s Science Page). One of the high points for me was the landing of NASA’s Curiosity on Mars. I am a big fan of the rovers, but Curiosity has captured my imagination in a way the other rovers never did. I think it is the name; was ever an exploratory robot craft ever given a better title?
Curiosity has four main scientific goals:
1/ Biological – to keep looking for evidence of organic compounds and biological processes;
2/ Geological – investigate the minerals and non-organic chemicals of the Martian surface;
3/ Climatological – determine water cycle and carbon dioxide cycle in an attempt to understand the Martian atmosphere; and
4/Radiation – to record the spectrum of radiation at the Martian surface.
From my personal viewpoint, it is the hunt for biological signatures that is the most interesting. It isn’t just intelligent life that fascinates me, though a positive SETI result would thrill me beyond belief, because all the forms that life can take are complex and unique. I consider all four of Curiosity’s goals are a link back to the search for evidence there is, or was, life on Mars.
To put things into some perspective, let’s contrast the known conditions for life on Earth with the possibility of life on Mars. Life on Earth can’t exist without water; so the theory goes that the presence of water would increase the probability of the presence of life. This meant I found the discovery of a stream bed by Curiosity very exciting. There can been evidence for free-flowing water gathered before, but it was ambiguous. Now there can be no doubt that Mars does have periods where water flows just like here on Earth.
Life went a long way to changing the face of our planet Earth. The increase in oxygen cause by the respiration of living organisms, and many new minerals were formed by the processes of oxidation. Bacteria, microbes and lichens changed the chemical composition of some types of rocks. Limestone is the remains of billions upon billions of skeletal fragments of ancient marine organisms; coal is the remains of Carboniferous-era peat bogs and forests; and oil and gas are the fossilised remains of zooplankton and algae. So, it seems self-evident that the presence of similar minerals on Mars would indicate life was present once, if lo longer, on the Red Planet.
It may seem to the observer that Mars is too hostile an environment to life, with its lack of water and atmosphere, extremes of temperature and high levels of radiation. However, here on Earth, microorganisms are found in almost every habitat present in nature. On Earth we have extremophiles; life forms that exist – nay, thrive – in the harshest and difficult environments. The surface of Mars is comparable to some of the niches that are exploited by microorganisms here on Earth.
On the down side of discovering these tough organisms on Mars would be the risk of disease or cross-contamination if we ever send a team of astronauts to Mars. Such organisms might find our warm and watery bodies the perfect substrate for reproduction, a luscious paradise after struggling to thrive under arid conditions. Alternatively, the organisms might find our bodies too different to adapt too – instead, our own organisms might escape into the Martian environment and overwhelm the native population of organisms and create a tragedy of the scale of the introduction of smallpox to the American native peoples.
The history of exploration isn’t always a happy one.
But I am an optimist. I hope we do find life on Mars. This would greatly increase the probability that life appears wherever possible. In our galaxy alone, that would mean thousands, maybe millions, of other planets would contain and sustain life. And I love the idea that our planet isn’t the only one to have a rich and wonderful ecology. There should be analogues to butterflies, penguins and camels on other planets … and maybe even people analogues.
*The Voyager Science Queen is also known as Lynne Lumsden Green- find out who she is in About Our Contributors!