I am interested in climate change and other topics too. But this thing is so huge, in the worst case we are talking about the end of our civilization.

We can both prevent asteroid impacts and address climate change. It's not either-or.

You see the Earth as a bright blue and white Christmas tree ornament in the black sky. It's so small and so fragile - you realize that on that small spot is everything that means everything to you; all of history and art and death and birth and love.

Asteroids have hit the Earth millions of times. We can see them as shooting stars every night. When they get bigger, things get complicated. It is only a matter of time until a big one hits us. And since we can do something about it, we should.

As you pass from sunlight into darkness and back again every hour and a half, you become startlingly aware how artificial are thousands of boundaries we've created to separate and define. And for the first time in your life you feel in your gut the precious unity of the Earth and all the living things it supports.

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

While we didn't know the dinosaurs personally, we do know that they were wiped out by an asteroid impact.