Here's a nice press release (http://neo.jpl.nasa.gov/news/news182a.html http://neo.jpl.nasa.gov/news/news182a.html) regarding the impact of a small NEO (2-3 met

Here's a nice press release (http://neo.jpl.nasa.gov/news/news182a.html http://neo.jpl.nasa.gov/news/news182a.html) regarding the impact of a small NEO (2-3 meters in size) last month with Earth. Being small, it was discovered only 21 hours before impact, and its sonic signature is believed to have been observed in the mid-Atlantic around Bermuda. Larger asteroids with orbits that will come near Earth's are being discovered routinely by sky surveys (e.g., Catalina, http://www.lpl.arizona.edu/css/css_mission.html http://www.lpl.arizona.edu/css/css_mission.html) as far away as Jupiter.