There are two ways to be rich: to have more or need less. It's estimated that we squander about 30 percent of our energy leaving the lights on, the refrigerator door open, and so on. Then there is the enormous amount of food that we expend huge amounts of energy to raise and then throw away.

By the way, most of the light that comes from the sun is green.

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.

We are just a speck, on a speck, orbiting a speck, in the corner of a speck, in the middle of nowhere.

As you may know, I am a mechanical engineer.

Everybody remembers numbers and computers remember numbers. People remember procedures and computers certainly remember procedures. But the other thing that's still important is that your perception as a human is affected subtly by all this stuff that you can't quite articulate. You run your life according to all this stuff that's happened to you. All of your memories affect everything you do whereas with a computer, there's adaptive software and things, but it's more literal.

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