"If you're not learning, you're not living."

"My ideal day involves a lot of reading, a lot of thinking, and a lot of looking up at the stars."

"For me, I am a cosmic optimist. I always think that we will find solutions to our problems."

"The universe is a dangerous place. It's full of black holes and gamma-ray bursts."

"The greatest discovery is to find something you love to do and then figure out how to get paid for it."