Watch this recent episode of Colbert, and his interview with Michio Kaku, where they talk about the recent asteroids, and also about the much larger one "grazing" Earth's atmosphere in 2029, and that "may" hit Earth in 2036 (depending on how much it grazes Earth's atmosphere in 2029). It starts at 15:30 or so:

http://www.colbertnation.com/full-episodes/tue-february-26-2...