NASA instrument creates \'family tree\' of orbiting asteroids

NASA says data from its Wide-field Infrared Survey Explorer has yielded a new, improved family tree for asteroids in the main belt between Mars and Jupiter. Millions of infrared snapshots from the asteroid-hunting portion of the WISE all-sky survey, called NEOWISE, have helped identify 28 new asteroid \"families,\" NASA\'s Jet Propulsion Laboratory in Pasadena, Calif., reported Wednesday. An asteroid family is formed when a collision breaks a large parent body into fragments of various sizes. The snapshots helped place thousands of previously hidden and uncategorized asteroids into families for the first time, a critical step in understanding the origins of asteroid families and the collisions thought to have created these rocky clans, researchers said. \"NEOWISE has given us the data for a much more detailed look at the evolution of asteroids throughout the solar system,\" Lindley Johnson of the Near-Earth Object Observation Program at NASA Headquarters in Washington said. \"This will help us trace the NEOs back to their sources and understand how some of them have migrated to orbits hazardous to Earth.\" The main asteroid belt is a major source of near-Earth objects, those asteroids and comets that come within 28 million miles of Earth\'s orbit around the sun