Icy Centaurs

4 Aug 2010

Are icy centaurs between the orbits of Jupiter and Neptune a threat to the earth? is the headline of a piece by Casey Kazan at www.dailygalaxy.com August 2nd ... He says the greatest threat to earth comes from comets and NASA has found it difficult to keep a track on these objects. Most comets are on orbits that enter the inner solar system at intervals of two to three hundred years. The origin is unknown but it is suspected the source is the Centaurs - a million or so icy objects on elliptical orbits that come closest to the Sun between the orbits of Jupiter and Neptune. A new study of Trajan asteroids - these exist around the orbit of Neptune, concluded that these may go on to become comets that threaten other parts of the solar system, including the earth. Centaurs are on unstable orbits and are prone to nudging from the gavitational effect of Jupiter - or by other unknown causes. The population of Centaurs appear to decay but at the same time is being fed from somewhere. It is suggested the Centaurs are being replenished by the Trajan asteroids, becoming Centaurs when their orbit becomes erratic.