The best bet, AFAIK, is to paint it: http://www.scientificamerican.com/podcast/episode.cfm?id=shoo-away-asteroids-with-a-coat-of-13-02-26 http://www.scientifica

The best bet, AFAIK, is to paint it: http://www.scientificamerican.com/podcast/episode.cfm?id=shoo-away-asteroids-with-a-coat-of-13-02-26 http://www.scientificamerican.com/podcast/episode.cfm?id=sho... (No practical confirmation, of course, but the idea is supported by a lot of prominent physicists.)