The Big Bang banged, and for some reason we’re here. And that’s astonishing. And that we can understand that, that’s the most astonishing.

For me, the meaning of life is pretty clear: Living things strive to pass their genes into the future.

Burning carbon-based substances like oil, gas, and especially coal, produces billions of tons of extra carbon dioxide each year. Methane gas from cows and pigs and other animals on our large farms ends up in the atmosphere as well, trapping more of the sun's energy as heat.

The meaning of life is pretty clear: Living things strive to pass their genes into the future. The claim that we would not have morals or ethics without religion is extraordinary. Animals in nature seem to behave in moral ways without organized religion.

It is my mission to change the world. I'm not kidding: Make no small plans, dream mighty things. I feel if we get enough people engaged in climate change, we will get enough people to change the world. We will revolutionize the way we produce electricity and provide clean water to people.

Science provides a much more satisfactory way to seek answers than does any religion.

Speaking of human computers, there is a guy named Art Benjamin, he's a human calculator. He says it's a skill he learned as a kid. Now he's a math professor at Harvey Mudd. He can find the square root of a six digit number in a few seconds. Practice.