“Whether or not you can never become great at something, you can always become better at it. Don't ever forget that! And don’t say “I’ll never be good”. You can become better! and one day you’ll wake up and you’ll find out how good you actually became.”

“The good thing about science is that it's true whether or not you believe in it.”

“When you visit countries that don't nurture these kinds of ambitions, you can feel th absence of hope...people are reduced to worrying only about that day's shelter or the next day's meal. It's a shame, even a tragedy, how many people do not get to think about the future. Technology coupled with wise leadership not only solves these problems but enables dreams of tomorow.”

“The most accessible field in science, from the point of view of language, is astrophysics. What do you call spots on the sun? Sunspots. Regions of space you fall into and you don’t come out of? Black holes. Big red stars? Red giants. So I take my fellow scientists to task. He’ll use his word, and if I understand it, I’ll say, “Oh, does that mean da-da-da-de-da?”

“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 pea-brained dinosaurs.”

“So you're made of detritus [from exploded stars]. Get over it. Or better yet, celebrate it. After all, what nobler thought can one cherish than that the universe lives within us all?”

“In 2002, having spent more than three years in one residence for the first time in my life, I got called for jury duty. I show up on time, ready to serve. When we get to the voir dire, the lawyer says to me, “I see you’re an astrophysicist. What’s that?” I answer, “Astrophysics is the laws of physics, applied to the universe—the Big Bang, black holes, that sort of thing.” Then he asks, “What do you teach at Princeton?” and I say, “I teach a class on the evaluation of evidence and the relative unreliability of eyewitness testimony.” Five minutes later, I’m on the street. A few years later, jury duty again. The judge states that the defendant is charged with possession of 1,700 milligrams of cocaine. It was found on his body, he was arrested, and he is now on trial. This time, after the Q&A is over, the judge asks us whether there are any questions we’d like to ask the court, and I say, “Yes, Your Honor. Why did you say he was in possession of 1,700 milligrams of cocaine? That equals 1.7 grams. The ‘thousand’ cancels with the ‘milli-’ and you get 1.7 grams, which is less than the weight of a dime.” Again I’m out on the street.”