Posted: Tue, Mar 2, 2004, 3:28 PM ET (2028 GMT)
Data collected by NASA's Mars rover Opportunity have led scientists to conclude that at least one region of Mars was once "drenched" in liquid water. Scientists revealed their findings at a highly-anticipated press conference Tuesday afternoon at NASA Headquarters in Washington. Various lines of evidence led researchers to conclude that liquid water once flowed through the rocks in the Meridiani Planum region of Mars, altering their texture and chemistry. Spectrometers on Opportunity detected high concentrations of salts in exposed rocks in the area, including a hydrated iron mineral called jarosite usually associated with acidic lakes and hot springs. Opportunity's camera also showed the rocks had indentations, spherules, and crossbedding, features that combined are associated with exposure to liquid water. Scientists said they don't know yet if the rocks were simply exposed to water after they formed or if they were laid down by minerals collecting at the bottom of a lake or ocean.

Related Links:

•  SPACE.com article
•  AP article
•  Reuters article
•  NASA press release