A team of astronomers from Armagh Observatory and the University of Buckingham report that the discovery of hundreds of giant comets in the outer planetary system over the last two decades means that these objects pose a much greater hazard to life than asteroids. The team, made up of Professors Bill Napier and Duncan Steel of the University of Buckingham, Professor Mark Bailey of Armagh Observatory, and Dr David Asher, also at Armagh, publish their review of recent research in the December issue of Astronomy and Geophysics (A and G), the journal of the Royal Astronomical Society. The giant comets, termed centaurs, move on unstable orbits crossing the paths of the massive outer planets Jupiter, Saturn, Uranus and Neptune. The planetary gravitational fields can occasionally deflect these objects in towards the Earth. Read http://www.spacedaily.com/reports/Giant_comets_could_pose_danger_to_life_on_Earth_999.html
