Except in pure mathematics, nothing is known for certain (although much is certainly false).

Somewhere, something incredible is waiting to be known.

It is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring.

The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.

Imagination will often carry us to worlds that never were. But without it we go nowhere.

I don't want to believe. I want to know.

The absence of evidence is not the evidence of absence.

The brain is like a muscle. When it is in use we feel very good. Understanding is joyous.

We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.

For small creatures such as we the vastness is bearable only through love.

You have to know the past to understand the present.

And so Discovery drove on toward Saturn, as often as not pulsating with the cool music of the harpsichord, the frozen thoughts of a brain that had been dust for twice a hundred years.

As long as you are still breathing, you definitely haven't reached your highest potential on earth. Always challenge yourself to do better.

Most entertainment is trying to get you. It's tested, like toothpaste.

I like to joke that I started writing long poems out the anxiety over ending and starting poems. It just seemed easier to keep going.

Compassion, along with love, is the face of altruism.

You can spend your whole life trying to be popular, but at the end of the day, the size of the crowd at your funeral will be largely dictated by the weather.

. . . Endlessness is a really strange idea in a universe that is defined by its endings.

The whole world may not understand me, but I don’t care.

I have been eating poetry.

If those who give are conscious of their own generosity and those who receive feel indebted, they are no longer family but rather strangers doing business.