spacetoday.net: Opportunity reveals evidence for standing water on Mars

Posted: Tue, Mar 23, 2004, 8:15 PM ET (0115 GMT)
Mars rock with ripples caused by water (NASA/JPL)

Data from NASA's Mars rover Opportunity have led scientists to conclude that the Meridiani Planum region of Mars once was on the shore of a salty body of water. At a press conference Tuesday afternoon, scientists said two lines of evidence led them to conclude that the region was once home to standing or gently flowing water. The rover's camera observed bedding patterns in rocks at the spacecraft's landing site, features scientists said were most likely formed by water at least five centimeters deep. The rover's spectrometers also detected high concentrations of chlorine and bromine in the rocks, caused by salts precipitating out of water as it evaporated. Planetary scientists said they don't know how large the body of water was or how long it was there, but they did say the area was reminiscent of "playas" on Earth, salt flats that occasionally fill with water before evaporating. The rover detected no evidence of biological activity, although NASA officials said the area was now on the top of their list of places on Mars to visit on future missions that will be equipped with astrobiological experiments.