The White House uploaded this brief video of Stephen Hawking to its official YouTube channel today. The clip comes from an August 2009 interview.
"As a small boy, I used to take things apart," says Hawking. "I wanted to find out how they work. That is still what I want, but I've moved on to bigger things like the Universe."
"The thrill of discovering something no one knew before is like nothing else I know," he adds. "I want to share my excitement with everyone. My main challenge has been Lou Gehrig's Disease or ALS. I have had it since I was 21, but it has not prevented me from exploring the universe with my mind or having three wonderful children."
Hawking turned 71 today.