A near-Earth asteroid as wide as the Statue of Liberty is tall could strike Earth on Dec.22, 2032, alerting planetary defense groups at the United Nations.

Here are today's general risks from asteroids or comets both tiny and very large. Importantly, even relatively small rocks can still be threatening, as the surprise 56-foot (17-meter) rock that exploded over Russia and blew out people's windows in 2013 proved.