How serious does an asteroid threat have to be before we take action?

As the world waited for today's close flyby of the asteroid 2012 DA14, a small asteroid broke up over Chelyabinsk Russia this morning, blasting in city windows with its sonic boom and injuring hundreds. Meanwhile, NASA's Near-Earth Object Program has revised the odds of asteroid 2011 AG5 hitting the Earth in 2040 to… » 2/15/13 9:10am 2/15/13 9:10am

Is SETI at risk of downloading a malicious virus from outer space?

We take it for granted that the search for extraterrestrial intelligence (SETI) is a safe endeavor. Seriously, what could possibly go wrong with passively searching for interstellar radio signals? Unfortunately, the answer is quite a lot –- especially if the incoming signal contains something malicious, like a… » 6/27/12 2:39pm 6/27/12 2:39pm