.THE APPLICATION of Bayesian inversion to a variety of lithologic criteria in an evaluation of seismic records barely appears the stuff of headings. But when the seismic data you are actually examining arised from Mars, and also when your reasoning advises that the best illustration for them is fluid water in the pores in between stones, you have an account. There is dwarfs crave extra, when it involves nomadic scientific research, than water on Mars. Why performs the possibility prompt such enthusiasm-- and also what does this new analysis add to the story?