Arsenic Bacterium

On December 2nd NASA scientists announced the discovery of a very unusual type of bacterium. The scientists claim that the bacterium replaces phosphorus with arsenic in essential biochemical molecules - such as DNA. This is surprising as biochemists consider that phosphorus is one of the six building blocks of all known life forms. The other five are: carbon, hydrogen, nitrogen, oxygen, and sulfur.

Before serious consideration of this finding, XKCD has an interesting take on the finding:


Source: http://xkcd.com/829/

Here is a link to NASA's web page announcement of the discovery.

The videos below cover the NASA press conference (unfortunatley the audio is our of synch):







A couple of times Felisa Wolfe-Simon mentioned the Pale Blue Dot. Here is my post on that topic.

Not everyone is convinced as this link shows. There will be considerable discussion of this finding in the scientific community.

RealClimate has an interesting take on the issues raised in this post. There are links to critics of the study, but the most interesting points made by the post are the three general ones about the nature of science, quoted below.

Lesson one: Major funding agencies willingly back studies challenging scientific consensus.

Lesson two: Most everyone would be thrilled to overturn the consensus. Doing so successfully can be a career-making result. Journals such as Science and Nature are more than willing to publish results that overturn scientific consensus, even if data are preliminary – and funding agencies are willing to promote these results.

Lesson three: Scientists offer opinions based on their scientific knowledge and a critical interpretation of data. Scientists willingly critique what they think might be flawed or unsubstantiated science, because their credibility – not their funding – is on the line.