We have the capability - physically, technically - to protect the Earth from asteroid impacts. We are now able to very slightly and subtly reshape the solar system in order to enhance human survival.
When you look at the origins and evolution of life on Earth, it's been severely affected by asteroid impacts through history.
Americans who read the papers or watch Jay Leno have been aware for some time now that there is a slim but real possibility - about 1 in 45,000 - that an 850-foot-long asteroid called Apophis could strike Earth with catastrophic consequences on April 13, 2036.
When you have an asteroid threatening Earth, it's uncertain where it's going to hit until the last minute; the decision to take action has to be coordinated by the international community.