Water on Mars

Okyama University2007.06.18.

Akos Kereszturi, PHDCollegium Budapest

Eotvos Lorand University of SciencesHungarian Astronomical Association

e-mail: kru@mcse.hu

Change of our veiw on ancient Mars

Bone dry planet (Mariner-9)...

…ancient channels (Viking probes)...

Change of our veiw on ancient Mars

…sometimes lakes (MGS)...

Change of our veiw on ancient Mars

…with a great northern ocean (MGS, MEX).

Change of our veiw on ancient Mars

H2O budget

Signs of liquid water: • channels, valleys• ocean shorelines• clay minerals• sediments deposited in water• theoretical models

Original H2O budget: 20-400 m global coverage

The poposed ancient ocean

Channels by surface runoff or sapping

Global cooling, surface freezing

Realtive small planetary mass:• small radioactive heat source• early stopped dinamo• weak gravity• fast atmospheric loss• decreasing greenhouse effect• decreasing volcanism• only early global tectonism• decreasing global temperature• formation of cryosphere

Water break up, outflow channels

Favourable periods for liquid water

sedimentarydelta

lakesediments

SouthPolarCap

- Argyre- Uzboichannelsystem

Channel network water source

H2O distribution today

Almost all H2O is frozen:• 60-80 % subsurface permafrost• 10-30 % polar cap and polar sediments• 0,1-0,01 % atmosphere

Signs of water today? - Gullies?

Slope straks?

DDS „seepages”?

Possible conditions for water today

• very rarely• who knows…