is defined as the average risk posed by objects of the same size or larger over the years until the date of the potential impact. References External links UH Observations Result in "All Clear" for Potential Asteroid Impact (Institute for Astronomy at the University of Hawaii December 21, 2012) Phew! One Less Asteroid Impact to Worry About (Phil Plait Dec. 22, 2012) Table of next close approaches (Sormano Astronomical Observatory) MBPL - Minor Body Priority List (Sormano Astronomical Observatory) 367789 367789 367789 367789 20110108 20230203 20110108