"The impact on Earth from a 3,000-foot-wide asteroid would cause an explosion equivalent to 40,000 megatons of TNT—and would likely end human civilization altogether, regardless of where it hit. The odds that such an asteroid impact would make us the last generation of human civilization are no lower than the odds of an average American dying in an earthquake (about 0.001%). \\ The chance in your lifetime of an asteroid impact with explosive energy of 100 megatons of TNT is about 1%. Such an impact would deliver many times the explosive energy of all the munitions used in World War II, including the atomic bombs." - Adriano

(thought the Lord part of the title added drama... well, Rees is an astronomer royal of the U.K. :-) "The B612 Foundation was established in 2002 and since 2012 has been building the Sentinel Space Telescope to find threatening asteroids before they find us. It is part of the most ambitious and important private space mission in history. The Sentinel telescope will give humanity decades of warning before a future asteroid impact so we can employ space technology to protect the planet." Always plan ahead. - Adriano

This is a video from today... http://www.bbc.co.uk/news... (and here https://www.youtube.com/watch...) meteorite landing in the Urals.. You never know when something will fly out of the sky. ;-) - Amira

See also discussion on Quora: http://www.quora.com/Meteor-... and this latest NASA paper: Yarkovsky-driven impact risk analysis for asteroid (99942) Apophis http://arxiv.org/abs... [Yarkovsky effect http://en.wikipedia.org/wiki...] - Amira