A Killer Asteroid Is Coming - We Don't Know When (So Let's Be Ready), Bill Nye Says

Coordination is the next step after detection, Nye said. A big asteroid hurtling toward Earth would be a global issue, so the international community would have to work together to deal with it. 

And we'd have several options at our disposal. If we had enough warning time — years or, preferably, decades — we could launch a probe to fly alongside the asteroid, gradually nudging the rock off course via a gravitational tug. This "gravity tractor" craft would ideally boost its pull by plucking a big boulder off the asteroid, said NASA Chief Scientist Jim Green, who participated in yesterday's event with Nye.