Water found on asteroid

Physics Today : The first-ever discovery of ice and organic molecules on an asteroid may hold clues to the origins of Earth’s oceans and life 4 billion years ago.University of Central Florida astronomers detected a thin layer of water ice and organic molecules on the surface of 24 Themis , the largest in a family of asteroids orbiting between Mars and Jupiter.Their unexpected findings were published in Nature."What we’ve found suggests that an asteroid like this one may have hit Earth and brought our planet its water,” said UCF astronomer Humberto Campins, the study’s lead author.Some theories suggest asteroids brought water to Earth after the planet formed dry. Scientists say the salts and water that have been found in some meteorites support this view.Using NASA’s Infrared Telescope Facility in Hawaii, Campins and his team of researchers measured the intensity of the reflected sunlight as 24 Themis rotated. Differences in intensity at different wavelengths helped researchers determine the makeup of the asteroid’s surface.They were surprised to find ice and carbon-based compounds evenly distributed on 24 Themis. More specifically, the discovery of ice is unexpected because surface ice should be short lived on asteroids, which are expected to be too warm for ice to survive for long.Perhaps most promising hypotheses to explain the ice, is the possibility that 24 Themis might have preserved the ice in its subsoil, just below the surface, as a kind of “living fossil” or remnant of an early solar system that was generally considered to have disappeared long ago. Related link Water ice and organics on the surface of the asteroid 24 Themi