The United Nations General Assembly may approve a plan soon for the world's space agencies to defend the Earth against asteroids. The plan, introduced last week, is expected to be adopted by the General Assembly in December. It would do two things: create an International Asteroid Warning Network so countries can share what they know about asteroids; and spin up a group of scientists from several countries' space agencies to look for smaller asteroids, as well as make plans to divert them away from the Earth.