Observations by astronomers tracking near-Earth asteroids have raised a new object to the top of the Earth-threat list. The asteroid could strike the Earth in 2102. However, Don Yeomans, manager of NASA's Near Earth Object Program at the Jet Propulsion Laboratory in Pasadena, California, US, told New Scientist: "The most likely situation, by far, is that additional observations will bring it back down to a zero." He adds: "We're more likely to be hit between now and then by an object that we don't know about." On 23 February, new observations allowed researchers to more accurately calculate the orbit of...