Word: knoll
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Clues found in the rocks by two NASA space rovers—Opportunity and Spirit—have led researches to conclude that the concentrations of minerals in Mars’s water makes the planet inhospitable for even the heartiest of organisms, according to Andrew Knoll, a professor of natural history in the Earth and planetary sciences department and a member of NASA’s Mars Exploration Rover science team...
...particular iron sulfate mineral called jarosite forms only under strongly acidic conditions,” Knoll said. “Its identification in the Martian rocks provides a smoking gun for strongly acidic conditions...
...Knoll said that differences in size and distance from the sun caused Earth and Mars to become distinct early in their lives...
...About 3.8 billion years ago—the age of the sedimentary rocks collected by Opportunity—Earth had oceans, life, and an atmosphere capable of sustaining greenhouse warmth but without oxygen,” said Knoll, who added that the calculations on ancient water activity on Mars were performed by Harvard postdoctoral fellow Nicholas J. Tosca. “Mars was dry, acidic, and at least mildly oxidizing...
...Most of Mars remains unvisited by rovers, although orbiting satellites are providing good maps of surface conditions across the planet,” Knoll said...