If you took every nuclear weapon ever built at the height of the Cold War, lumped them together and blew them up at the same time, that would be one one-millionth of the energy released at that moment.

When you're dealing with the universe, ignorance can be deadly.

I'm tired of ignorance held up as inspiration, where vicious anti-intellectualism is considered a positive trait, and where uninformed opinion is displayed as fact.

Not everything that’s cool is science, but everything in science is cool.

If a little kid ever asks you just why the sky is blue, you look him or her right in the eye and say, 'It's because of quantum effects involving Rayleigh scattering combined with a lack of violet photon receptors in our retinae.'

Welcome to science. You’re gonna like it here.

You can experience the thrill of discovery, the incredible, visceral feeling of doing something no one has ever done before, see things no one has ever seen before, know something no one has ever known before. ... Welcome to science, you're gonna like it here.

The Universe is cool enough without making up crap about it.

Pseudoscience is like a virus. At low levels, it's no big deal, but when it reaches a certain threshold it becomes sickening.

It’s dead obvious that creationism isn’t science, or even bad science. It’s nonsense. But I’ve long stated it’s also bad religion, because it doesn’t just take faith, it also takes a phenomenal disregard of reality.

A lot of them complain because they say the word denial puts them in the same bin as holocaust deniers. That's too bad. But the thing is, they do have something in common: a denial of evidence and of scientific consensus.

The best idea ever thought of in the history of humanity is useless unless someone communicates it. It will die in the test tube. And in our case, what we're communicating here to people is not necessarily something they want to hear. And so, our demeanor - how we deliver this message - takes on crucial, crucial importance.

The difference between the dinosaurs and us is that we have a space program and we can vote...

Sometimes, even by accident, the universe makes beauty, and we can stand back in awe of it. Even better - we can figure out why. Science! I love this stuff.

Teach a man to reason and he will think for a lifetime.

Humanity and life are reflected in the stars, and the Universe itself is poetry.

Other job markets may lay claim to the title, but astronomy is actually the world's oldest profession.