Hidden asteroids are stalking the Earth

A 10-metre rock that buzzed Earth last week is the 'poster child' for a small class of asteroids whose orbits make them nearly impossible to spot

http://feeds.newscientist.com/c/749/f/10898/s/8c55cc1/l/0L0Snewscientist0N0Carticle0Cmg20A5274440B10A0A0Ehidden0Easteroids0Eare0Estalking0Ethe0Eearth0Bhtml0DDCMP0FOTC0Erss0Gnsref0Fspace/story01.htm