.THE app of Bayesian inversion to a variety of lithologic guidelines in an examination of seismic data barely seems the stuff of headings. Yet when the seismic information you are actually evaluating come from Mars, and also when your thinking suggests that the very best illustration for them is liquid water in the pores between stones, you have an account. There is little people thirst for much more, when it involves planetary scientific research, than water on Mars. Why performs the prospect provoke such pleasure-- as well as what performs this brand-new analysis contribute to the account?