If humans one day become extinct from a catastrophic collision, there would be no greater tragedy in the history of life in the universe. Not because we lacked the brain power to protect ourselves but because we lacked the foresight. The dominant species that replaces us in post-apocalyptic Earth just might wonder, as they gaze upon our mounted skeletons in their natural history museums, why large headed Homo sapiens fared no better than the proverbially peabrained dinosaurs.

Stars die and reborn […] They get so hot that the nuclei of the atoms fuse together deep within them to make the oxygen we breathe, the carbon in our muscles, the calcium in our bones, the iron in our blood. All was cooked in the fiery hearts of long vanished stars. … The cosmos is also within us. We're made of star stuff. We are a way for the cosmos to know itself.

There is a growing awareness that we're losing our technological competitive edge. I think there's an awareness that we're losing our leadership, and that maybe our self image over the past several decades has been a little bit delusional.

Some air you inhale was exhaled by Cleopatra.

As they are currently practiced, there is no common ground between science and religion... Although just as in hostage negotiations, it's probably best to keep both sides talking to each other.

The remarkable feature of physical laws is that they apply everywhere, whether or not you choose to believe in them. After the laws of physics, everything else is opinion.

In the first year of a child's life we teach them to walk and talk. And then for the rest of their lives we want them to sit down and be quiet.