Atom & Cosmos

Hidden ocean on Saturn’s moon The south pole of Saturn’s moon Enceladus — where geysers of ice and water vapor spew from beneath the body’s surface — emits more than twice as much heat each second as researchers had estimated, according to a report by Carly Howett of the Southwest Research Institute in Boulder, Colo., and her colleagues. The higher heat output, which is based on a new, more accurate analysis of measurements recorded by the Cassini spacecraft, makes it significantly more likely that icy Enceladus has a subsurface layer of liquid water, the team reports in a paper to appear in the Journal of Geophysical Research–Planets . The finding shines a brighter spotlight on the moon as an intriguing target for astrobiological studies, the researchers say. — Ron Cowen Salt of life on Mars Planetary scientists have new evidence that part of Mars was covered by an ocean several billion years ago and a new focus on where to search for life on the planet, they report in an article to appear in Icarus . Chris McKay of NASA’s Ames Research Center in Moffett Field, Calif., and collaborators say that water once covered a 30,000-square-kilometer area of a basin called Terra Sirenum. Salt flats in the basin, along with certain minerals that lie near the flats, appear to have been deposited by water. These deposits could be key places to look for existing life and may also have preserved evidence of past life on Mars. — Ron Cowen Fringe Jupiter A continuing analysis of the orbits of comets hints that a planet one to four times as massive as Jupiter might be lurking at the icy fringes of the solar system, scientists at the University of Louisiana in Lafayette report in the February Icarus . If the rogue planet truly exists, the researchers say, it should be spotted over the next two years as ground-based telescopes study in detail outer solar system objects spotted by NASA’s WISE infrared spacecraft. — Ron Cowen