There is no doubt that early Mars had long period of warmer and much wetter climates before its atmosphere thinned too much to retain that liquid H 2 0 on the surface.

As we know from the Curiosity mission to Gale Crater and other orbital findings, regions of that warmer and wetter Mars had flowing water and lakes periodically over hundreds of millions of years. That’s one of the great findings of planetary science of our times.

But before approaching the question of whether that water could have supported life, a lot more needs to be known than that water was present. We need answers to questions like how acidic or basic that water likely was? Was it very salty? Did it have mineral and elemental contents that could provide energy to support any potential life?

And most especially, how long did those wet periods last, and the dry periods as well?