"GLOBAL ISSUES, LEADERSHIP CHOICES":

"In May, a group of international scientists assembled near Washington, D.C., to tackle an alarming problem: what to do about an asteroid hurtling toward Earth. ... True, the chances of a civilization-destroying asteroid impact are exceedingly small, at least in the foreseeable future. Asteroid strikes that cause regional devastation and catastrophic global climate change occur, on average, only about once every 100,000 years or more. ... Over the past two decades, asteroid hunters with NASA and other international space agencies have identified and tracked the orbits of more than 20,000 asteroids—also known as near-Earth objects—that pass through our neighborhood as they orbit the sun. Of those, about 2,000 are classified as potentially hazardous—asteroids that are large enough (greater than 150 yards in diameter) to cause local destruction and that come close enough to Earth to someday pose a threat. ... On an unlucky Friday the 13th in April 2029, the thousand-foot-wide asteroid Apophis will pass a mere 19,000 miles from Earth—closer than the satellites that bring us DISH TV. But here’s the bad news: Hundreds of thousands of other near-Earth asteroids, both large and small, haven’t been identified. We have no idea where they are and where they are going. On Feb. 15, 2013, a relatively small, 60-foot-wide asteroid traveling at 43,000 mph exploded in the atmosphere near the Russian city of Chelyabinsk, sending out a blast wave that injured 1,500 people. No one had seen the asteroid coming. ... Nor is it clear that we could deflect a small but dangerous asteroid heading our way even if we did spot it. No asteroid-deflection method has ever been tested in real-space conditions.... Over its 4.5 billion-year history, Earth has been hit millions of times by powerful asteroids, and it will inevitably be hit again—whether two centuries from now or next Tuesday. So it isn’t a question of whether humankind will have to confront the prospect of a destructive asteroid hurtling our way; it is only a question of when." www.wsj.com/articles/the-asteroid-peril-isnt-science-fiction-11562339356