So, after the initial disappointment that the NASA announcement this week of the news that "would impact on the search for extraterrestrial life" turned out to involve microbes in a lake in California, I find myself growing genuinely excited at what this could mean.
The phrase "Life will find away" seems to get over used however this might actually prove to be true. These microbes once, back through the mist of time, constructed their D.N.A. in the way every other organism on earth does by using a framework built of phosphorous at selected points. Once these organism's habitat became cut off from fresh water Arsenic built up in the lake just as it has in lakes all over the world, most noticeably in Bangladesh where it has caused toxic poisoning in thousands of people who have no choice but to drink the water. In Mono Lake though these simple, by our standards, organisms have learnt to metabolise Arsenic. Not only eating it but replacing the phosphorous in their D.N.A. with Arsenic as well.
While this should not surprise us totally (Arsenic is directly below Phosphorous in the periodic table and so shares many of its attributes) no other life form on this planet has been proven to do this before! All of the life we know uses Phosphorus and is constructed from carbon, until now.
Now the question this raises for me is does life just use what is available within a certain parameter. As long as its in the same column could it instead pick Nitrogen or Antimony? Could an organism base itself on Silicon instead of Carbon. If this proves to be the case then searching for "Life as we know it" might be the biggest mistake we ever make. Planets we have ruled out because there is no way a carbon based life form could exist may just have become the very places we need to search. I really do believe that life exists in some form or another out there and I think we are getting closer to discovering it. I just hope that we haven't already missed it because we had narrowed out sights too much.
Thank you for your time