Wednesday, June 25, 2008

Nuthin But the Martian Rain

A new analysis of Martian soil data led by University of California, Berkeley, geoscientists suggests that there was once enough water in the planet's atmosphere for a light drizzle or dew to hit the ground, leaving tell-tale signs of its interaction with the planet's surface.

The study's conclusion breaks from the more dominant view that the liquid water that once existed during the red planet's infancy came mainly in the form of upwelling groundwater rather than rain.

To come up with their conclusions, the UC Berkeley-led researchers used published measurements of soil from Mars that were taken by various NASA missions: Viking 1, Viking 2, Pathfinder, Spirit and Opportunity. These five missions provided information on soil from widely distant sites surveyed between 1976 and 2006.

"By analyzing the chemistry of the planet's soil, we can derive important information about Mars' climate history," said Ronald Amundson, UC Berkeley professor of ecosystem sciences and the study's lead author. "The dominant view, put forward by many now working on the Mars missions, is that the chemistry of Mars 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. In this paper, we try to steer the discussion back by re-evaluating the Mars data using geological and hydrological principles that exist on Earth."

The final version of the study will appear online in Geochimica et Cosmochimica Acta, the journal of the International Geochemical Society, by the end of June, and in a print issue in August.


A bit early for the press release, but we'll see about the reaction.

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