NASA admits 1000s of 'city killer' asteroids still haven't been found
Tens of thousands of undetected near-Earth asteroids at least 140 metres wide remain, and Earth currently lacks a ready spacecraft capability to actively deflect them.
Today in History: September 26, Biosphere 2 stay begins in Arizona
Sept. 26 marks varied historical events including Biosphere 2, major political milestones, disasters, legal actions, space missions, and catastrophic hurricanes.