As the plow pushes through a parking lot of light fluffy snow, the snow clumps together in bigger and bigger chunks. Out in space, pressure hitting a gas cloud has a similar effect, except, instead of snowballs, you get stars!

Somehow it's O.K. for people to chuckle about not being good at math. Yet if I said, 'I never learned to read,' they'd say I was an illiterate dolt.

Before we start talking about genetic differences, you gotta come up with a system where there's equal opportunity.

Nothing is a thing: it's nothing. So I can imagine a place where there's not even nothing.

We account for all the matter and energy that we're familiar with, measure up how much gravity it should have, it's one-sixth of the gravity that's actually operating on the universe. We call that dark matter. It really should be called dark gravity. We don't know what that is.

I want people to see that the cosmic perspective is simultaneously honest about the universe we live in and uplifting, when we realize how far we have come and how wonderful is this world of ours.

When everyone agrees to a single solution and a single plan, there's nothing more efficient in the world than an efficient democracy.