It would take an extremely large spacecraft to deflect a large asteroid that would be headed directly for the Earth.

An asteroid can literally destroy 80 or 90 percent of the species that are alive on Earth. These are big events. I mean, this is called extinction.

When you look at the origins and evolution of life on Earth, it's been severely affected by asteroid impacts through history.

By preventing dangerous asteroid strikes, we can save millions of people, or even our entire species. And, as human beings, we can take responsibility for preserving this amazing evolutionary experiment of which we and all life on Earth are a part.

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.

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.