re: Nut theory for the day
The outburst flood channels were undoubtedly produced by a huge flow of fluid, not slowly over time by seepage.
I have problems with the Malin and Edgett gullies being produced by subsurface fluids, since they are sourced from near the tops of slopes, not near the base.
OTOH, I can live with concentrated sulphuric acid in the soils - But, why aren't the rover wheels fizzing?