The search for life on Jupiter’s moon Europa may have gotten easier. Planetary scientists Robert Pappalardo and Amy Barr of the University of Colorado at Boulder theorize that rust-colored dots on Europa are blobs of mineral-rich ice that rose to the top of the satellite’s frozen crust. These flows could
Courtesy of NASA/SPL/PIRL/University of Arizona
have dragged any deep-living microbes close to the surface.
Heated by a gravitational tug-of-war with Jupiter and its other large moons, Europa may have a warm ocean beneath its icy surface—a plausible breeding ground for life. But scientists have been daunted by the challenge of designing an instrument that could bore down through a dozen miles of ice to find out. Using computer modeling to interpret images from NASA’s Galileo satellite, Pappalardo and Barr demonstrated that acnelike markings on Europa’s surface are probably bits of ice containing minerals such as chloride salts and sulfuric acid, which lower the melting point so the material can rise from deep below. “These blobs act as elevators, and if there are microbes down there, maybe they’re carried up as well,” says Pappalardo. A proposed mission to search for signs of life on Europa could be launched as early as 2011.