Every time you look up at the sky, every one of those points of light is a reminder that fusion power is extractable from hydrogen and other light elements, and it is an everyday reality throughout the Milky Way Galaxy.

By exploring other worlds we safeguard this one. By itself, I think this fact more than justifies the money our species has spent in sending ships to other worlds. It is our fate to live during one of the most perilous and, at the same time, one of the most hopeful chapters in human history.

For me, the most ironic token of [the first human moon landing] is the plaque signed by President Richard M. Nixon that Apollo 11 took to the moon. It reads, ‘We came in peace for all Mankind.’ As the United States was dropping seven and a half megatons of conventional explosives on small nations in Southeast Asia, we congratulated ourselves on our humanity. We would harm no one on a lifeless rock.

We are a way for the cosmos to know itself.

The Big Bang is our modern scientific creation myth. It comes from the same human need to solve the cosmological riddle [Where did the universe come from?]

Whatever the reason you're on Mars, I'm glad you're there, and I wish I was with you.

Who is more humble? The scientist who looks at the universe with an open mind and accepts whatever the universe has to teach us, or somebody who says everything in this book must be considered the literal truth and never mind the fallibility of all the human beings involved?