‘Several earth like planets have recently been discovered, each thought to have once harboured conditions necessary to support life.’ Statements such as these irritate me – and I’m sure they irritate any other open minded scientist as well. Earth like? Able to support life? Yes, life as we know it but if I’m honest, ‘life as we know it’ is insignificant on any scale as far as the universe is concerned. It’s no secret that I’m no respected astronomer but I’m sure it’s time for such scientists to embrace a little more creativity and imagination. It’s time to comprehend the fast that conditions suitable for life could completely ignore our current understanding.
Many biologists seem to have conveniently forgotten GFAJ-1, a strain of bacteria that can survive in arsenic. Yes, this bacteria actually incorporates arsenic into it’s DNA and therefore it’s proteins. This goes against one of our current accepted rules that all living organisms need phosphorus – an element that is used to make DNA. By being able to use arsenic, GFAJ-1 has provided an example that is exempt to at least one of the limitations we have lain. One small crack in this new frontier is that arsenic is chemically similar to phosphorus – both being in group 5 of the periodic table meaning they react in alike ways. Obviously, this is a massive discovery but doesn’t come close to smashing down all of the barriers around our search for extra terrestrial life.
Another huge breakthrough comes in the form of muliti-cellular organisms that don’t need oxygen to survive. Previously, only prokaryotic single celled organisms were thought to be able to survive without oxygen. The organism discovered didn’t have mitochondria – which makes since –but instead had organelles with a similar function, but an anaerobic chemistry.
The fact can’t be denied however that ‘the big one’ (water) still hasn’t been cracked. And while it is indeed frustrating to hear those familiar words ‘water may have once flown here’ we will have to deal with it until chemical or biological proof shows otherwise. However, one small group within NASA are instead chasing life by using amino acids and proteins as traces. It’s still a limitation, but it’s more understandable. It can’t be denied that narrowing our searched could lead to vast quantities of life slipping through our grasps, until we know more, there’s not much we can do.