Geez, the economic and international news isn't bad enough. Now the University of Arizona reports that its Catalina Sky Survey (CSS) found 565 "potentially hazardous asteroids and comets that could approach the Earth" or Near-Earth Objects (NEOs) in 2008, breaking their own record of 460 NEOs in 2007. [right, the 60-inch telescope on Mount Lemmon is one of three telescopes the Catalina Sky Survey. Credit, UA]
As of January 2, 2009, NASA's Near Earth Object Program observers had discovered 5,955 NEOS, including 763 asteroids at least 1 kilometer in diameter. Of those, 1,008 NEOs larger than 140 meters have been found that come within 4.5 million miles of the Earth's orbit and are thus classified as potentially hazardous objects because they may be perturbed into impacting trajectories in the future.
According to a news post at UA, objects roughly 1,000 feet across, would explode with 24 times the energy of the world's largest thermonuclear bomb explosion, a 58-megaton Soviet bomb exploded in 1961, in an impact with Earth.
CSS is refurbishing a 40" telescope that will greatly improve astronomers abilities to track the NEOs after they're discovered. The CSS project also has been awarded a $3.16 million NASA grant to continue its search for NEOs through 2012. The CSS has discovered about 70% of all NEOs found in the last 3 years.