is an Apollo asteroid some in diameter and a Mars-crosser asteroid first observed on 20 November 2007, by Andrea Boattini of the Catalina Sky Survey. Early observations of caused excitement amongst the scientific community when it was estimated as having as high as a 1 in 25 chance of colliding with Mars on 30 January 2008. However, by 9 January 2008, additional observations allowed NASA's Near Earth Object Program (NEOP) to reduce the uncertainty region resulting in only a 1-in-10,000 chance of impact. most likely passed Mars at a distance of 6.5 Mars radii. Due to this relatively small distance and the uncertainty level of the prior observations, the gravitational effects of Mars on its trajectory are unknown and, according to Steven Chesley of NASA's Jet Propulsion Laboratory Near-Earth Object program, is currently considered 'lost' (see lost asteroids). Discovery The asteroid was discovered on 20 November 2007 by Andrea Boattini of the NASA-funded Catalina Sky Survey on Mount Lemmon, near Tucson, Arizona, United States, using a 1.5-meter telescope. It was discovered in the constellation Taurus at an apparent magnitude of +20. This is about 400,000 times fainter than most people can see with the naked eye on a dark night far from city lights. It was discovered nineteen days after passing near Earth. By the time it arrived at Mars it had an apparent magnitude of roughly +26 and therefore appeared over 100 times fainter than at the time of discovery. Mars encounter: chance of impact Timeline of observations and events 1 November 2007: Nineteen days before its discovery, this small asteroid passed within 7.5 million km (5 million miles or 0.0476 AU) of the Earth. 20 November 2007: The asteroid was first discovered by Andrea Boattini of the Catalina Sky Survey. 21 December 2007: was approximately halfway between Earth and Mars traveling at . It was estimated by NASA's Near Earth Object Program (NEOP) to have a 1-in-75 chance of colliding with Mars on 30 January 2008 at approximately 10:55 UT. It was thought it would pass about 50,000 km (0.00034AU) from Mars. 28 December 2007: NASA scientists at the Near-Earth Object program office at JPL announced they had found in 3 precovery images from 8 November 2007. The refined orbit placed the odds of a Mars impact at 1-in-25. The uncertainty region was reduced from 1 million km to roughly 400,000 km. The best fit trajectory had the