Snowstorm on comet observed by NASA spacecraft

Science News : NASA’s EPOXI spacecraft passed through a storm of fluffy, golf-ball-sized ice bodies as it whizzed past Comet Hartley 2 on 4 November, writes Ron Cowen in Science News. Hartley 2 is the first observed comet whose activity is powered by the sublimation of dry ice as it nears the Sun, creating jets of carbon dioxide gas that drag out particles of water-ice and dust along with it. Though the individual ice particles are thin, measuring only a few micrometers across, they clump together to form the much larger, fluffy chunks. “This whole thing looks like a snow globe that you’ve shaken,” said EPOXI scientist Peter Schultz of Brown University.