This planet seems to be in such sorry shape. And I can't ever think about the rest of the universe without coming back home and thinking what the implications for life here would be if we were to really have some definitive proof of extraterrestrial life.

Science has the cold facts, but lacks religion's social organization and ability to inspire that moves people to act.

Science reserves the highest reward for those of you who disprove our most cherished beliefs. At any moment someone from any walk of life could come forward and be responsible for a complete revision of our view of everything.

It is a great tragedy that science, this wonderful process for finding out what is true, has ceded the spiritual uplift of its central revelations: the vastness of the universe, the immensity of time, the relatedness of all life, and life's preciousness on our tiny planet.

It takes a fearless, unflinching love and deep humility to accept the universe as it is. The most effective way he knew to accomplish that, the most powerful tool at his disposal, was the scientific method, which over time winnows out deception. It can't give you absolute truth because science is a permanent revolution, always subject to revision, but it can give you successive approximations of reality.

My knowledge of science came from being with Carl, not from formal academic training. Carl gave me a thrilling tutorial in science and math that lasted the 20 years we were together.

Carl took on the military-industrial complex. He campaigned around the world for an end to the production of weapons of mass destruction. To him it was a perversion of science.