Let’s hope this evening’s Nasa press conference really does announce a form of bacterial life that uses arsenic.

Science bit: oxygen, hydrogen, carbon, nitrogen, sulphur and phosphorus are six necessary characteristics of all previously-known living organisms on Earth. These are needed to build DNA, proteins and fats and are some of the biological signatures of life we look for on other planets.

If true, it increases the likelihood of there being life on other planets quite considerably. I haven’t yet seen an estimate of any revision to the Drake equation.