Liquid water on Mars today?

Diedrich Moehlmann, DLR, set out to convince us that liquid water can and does temporarily exist between two surfaces such as two grains of rock in the upper surface of Mars today and to indicate where it may be found.

The puzzle for astrobiologists is that they know liquid water must have been plentiful in the past on Mars, but at present times we have only confirmed water ice and atmospheric water vapour. Water vapour can reach saturation in the current atmosphere of Mars, which makes it favourable for it to be bound to a surface. The Mars Phoenix lander found direct indication for liquid droplets on Mars.

Water in the upper surface of present Mars, shown by hydrogen enriched 

soil which is indicated by deep blue in this false-colour map of Mars

Credit: NASA/Feldman (Neutron spectrometer, Mars Odyssey)

Moehlmann introduced the concept of ‘deliquescence’ – a process that temporarily liquefies salts by uptake of atmospheric water. Deliquescence is a key process to repetitively form liquid brines on present Mars, as it can operate at remarkably low relative humidity. Iinner walls of cracks could be temporarily covered, and narrow tips filled, by liquid interfacial water.

He hypothesised that liquid brines in such cracks could form capillary networks, which would be protected habitats in the porous surface of Mars. Some recent flow-like events seen from features such as gullies on Mars may have been caused by growth of such a subsurface capillary network, with a sudden release of temporary liquid brines. These networks could be a possible environment that may be favourable to support life processes.

Click here for the full abstract of his presentation at EGU 2013.