Atom & Cosmos

Titan’s liquid-water ocean Known for its hydrocarbon lakes and methane-rich atmosphere, Saturn’s moon Titan may contain a water ocean beneath its icy shell, a new study suggests. The moon’s orbit, rotation and related properties can best be explained if Titan isn’t solid throughout but harbors a subsurface ocean of water, researchers from the Royal Observatory of Belgium in Brussels report in an upcoming Astronomy & Astrophysics . — Ron Cowen Io’s magma ocean runs deep A new study ends any doubt that Jupiter’s moon Io, the solar system’s most volcanically active body, has an internal ocean of magma. The study also reveals that the ocean must be more than 50 kilometers deep, researchers report online May 12 in Science . Krishan Khurana of UCLA and his collaborators base their findings on a reanalysis of data recorded by NASA’s Galileo spacecraft. — Ron Cowen Black-hole atoms Instead of evaporating, mini–black holes created during the Big Bang may survive and trap nearby particles into stable orbits, forming the gravitational equivalent of atoms. These survivors could contribute to the dark matter that makes up most of the cosmos’ mass. Such atomlike systems on or near Earth weighing at least 1,000 tons may be detected through emissions produced when the trapped matter falls from a higher to a lower energy state, just as electrons orbiting atoms do. Researchers from Sandia National Laboratories in Albuquerque and Halcyon Molecular in Redwood City, Calif., describe their idea in a paper posted May 3 at arXiv.org. If such systems exist, they would shed light on black hole evaporation and quantum gravity. — Ron Cowen ’SuperEarth’ may have liquid water Gliese 581d may be the first planet only a few times heavier than Earth that is known to reside in its star’s habitable zone, the region where water would remain liquid on the body’s surface. A team of French scientists came to that conclusion after detailed climate simulations of the planet, dubbed a superEarth because it weighs about 5.6 times Earth’s mass. Because of its relatively large distance from the star Gliese 581, the planet — one of six orbiting the star — had been thought too cold to have liquid water on its surface. But the new model says otherwise, the team reports in an upcoming Astrophysical Journal Letters . — Ron Cowen