Laboratory evidence is challenging theories that Mars’ ruddy surface came from a past when the planet was awash with water, New Scientist says. Defenders of this hypothesis say Mars’ reddish dust came from iron in rocks that over billions of years dissolved into the planet’s oceans, lakes and rivers. But US scientist Albert Yen of NASA’s Jet Propulsion Laboratory has assailed this idea, noting a strange discrepancy between Mars’ dusty topsoil and its rocks.
