Moisture on Mars
An analysis of Martian soil data led by UC Berkeley geoscientists suggests that there was once enough water in the planetís atmosphere for a light drizzle or dew to hit the ground, leaving tell-tale signs of its interaction with the planetís surface.
The studyís conclusion breaks from the more dominant view that the liquid water that once existed during the red planetís infancy came mainly in the form of upwelling groundwater rather than rain.
The UC Berkeley-led researchers used published measurements of soil from Mars that were taken by five NASA missions that provided information on soil from widely distant sites surveyed between 1976 and 2006.
ďBy analyzing the chemistry of the planetís soil, we can derive important information about Marsí climate history,Ē said Ronald Amundson, professor of ecosystem sciences and the studyís lead author. ďThe dominant view is that the chemistry of Marsí soils is a mix of dust and rock that has accumulated over the eons, combined with impacts of upwelling groundwater, which is almost the exact opposite of any common process that forms soil on Earth.Ē Whereas the UC Berkeley-led study does not delve directly into evidence of life on Mars, it does suggest what kind of climate that life, if it existed, might have encountered.
The planet is currently too cold for water to exist in a liquid state, but scientists generally agree that during the planetís earliest geological period, known as the Noachian epoch and dating 4.6 billion to 3.5 billion years ago, there were enough atmospheric greenhouse gases to warm the air and support lakes and flowing rivers.