A successful day for me is when I teach people something. They become enlightened by an idea and learn how to think about it, so that later on when someone says, "Tell me about x, y, z," they don't have to say, "I know this because Tyson told me." No, they'll say, "Here's why it's true because I know and understand it."

There are as many atoms in each molecule of your DNA as there are stars in the typical galaxy. This is true for dogs, and bears, and every living thing. We are, each of us, a little universe.

Our five senses are faulty data-taking devices, and they need help.

My only hope is that every other alien civilization isn't doing exactly what we are doing because then everybody would be listening, nobody would be receiving, and we would collectively conclude that there is no other intelligent life in the universe.

Trillions of years into the future, when all stars are gone...all parts of the cosmos will cool to the same temperature as the ever-cooling background. At that time, space travel will no longer provide refuge because even Hell will have frozen over. We may then declare that the universe has died-not with a bang, but with a whimper.

If you love what you do, you'll be your best at it compared to anything else you might have chosen as a career. Or at least you will love it more, and you won't lead a depressed day of your life.

In modern times, if the sole measure of what’s out there flows from your five senses then a precarious life awaits you.