Thomas Jefferson basically secularized Jesus.

The greatest explorer of recent decades is not even human.

The number of people in the world engaged in this search for catastrophic impactors totals one or two dozen. How long into the future are you willing to protect Homo sapiens on Earth? Before you answer that question, take a detour to Arizona's Meteor Crater during your next vacation.

The remarkable feature of physical laws is that they apply everywhere, whether or not you choose to believe in them. After the laws of physics, everything else is opinion.

In the animal kingdom, one of the keys to survival is to outwit your enemies. And when you're surrounded by carnivores, one of the best strategies is to fade into the background and disappear.

There is a theorem that colloquially translates, You cannot comb the hair on a bowling ball. ... Clearly, none of these mathematicians had Afros, because to comb an Afro is to pick it straight away from the scalp. If bowling balls had Afros, then yes, they could be combed without violation of mathematical theorems.

I grew up in New York City where there is no night sky. Nobody has a relationship with the sky, because, particularly in the day, there was air pollution and light pollution, and you look up, and your sight line terminates on buildings. You know the sun and maybe the moon, and that's about it. So what happens is that I am exposed to the night sky as you would see it from a mountaintop, and I'm just struck by it. Suppose I grew up on a farm where I had that sky every night of my life - then you're not going to be struck by it. It's just the wallpaper of your nighttime dome.