I can't think that leaving Earth once is enough.

Passion is what gets you through the hardest times that might otherwise make strong men weak, or make you give up.

The chunks of comet Shoemaker-Levy 9 were so large, and were moving so fast, that each hit Jupiter with at least the equivalent energy of the dinosaur-killing collision between Earth and an asteroid 65 million years ago. Whatever damage Jupiter sustained, one thing is for sure: it's got no dinosaurs left.

Science is like an inoculation against charlatans who would have you believe whatever it is they tell you.

I want to put on the table, not why 85% of the members of the National Academy of Sciences reject God, I want to know why 15% of the National Academy don’t.

Kids are born curious about the world. What adults primarily do in the presence of kids is unwittingly thwart the curiosity of children.

We went to the moon and discovered Earth.