On Feb. 15, asteroid 2012 DA14, discovered a year ago, cleared Earth by a scant 17,200 miles. The same day, a smaller, unrelated asteroid that no one saw coming exploded 12 to 15 miles above Russia’s Chelyabinsk region. Events that day highlight the risk that near-Earth objects (NEOs) can pose – although to some extent, humans can counter them.
NASA has whittled to four the number of potential landing sites for its 2016 mission to Mars to four featureless plots, to ensure a safe touchdown for its InSight lander, which will probe the Red Planet's interior.
Results: 1 of 9