My overview of the last couple of days at AGU, including the dark streaks paper.

Spacedaily article

When talking about "water" on Mars you need to keep track of when we are talking about, where on Mars, and what sort of "water".

I said earlier that for Noachian Mars, 3.7 Billion years ago, models of abundant liquid water were going out of favour.

The Ferris et al. study is of modern Mars, and things we don't properly understand. There was a good constructive discussion at AGU with Aharonsen, Ferris, Dohm, and various passers by, including myself.

To the amazement of all, I do not have a CO2-based model for these dark slope streaks. I doubt that they are formed by liquid water - we can measure various things about the streaks that don't fit a model of liquid water plus dust (i.e. mud).

Some sort of dry flurry of dust down the slopes could do it, but we need to model the circumstances better to understand what might be happening.