That survey was requested by America's Congress nearly a decade ago, and was stimulated in part by the dramatic images of Comet Shoemaker-Levy, whose collision with Jupiter in 1994 generated a great deal of public awareness of the risk of asteroid impacts. (A couple of Hollywood films exploring doomsday scenarios also swayed opinion.) In 2005 Congress ordered the survey that is about to start.
ECONOMIST: The American Association for the Advancement of Science