IF YOU HEAR ABOUT A SPEECH titled “Cosmology at the Frontier” and your mind wanders to space-age lip liner, don’t be ashamed. (We had the same thought.) But Brian Greene is no Mary Kay. This physicist, sometime film actor and author of the best-selling book, The Elegant Universe, is unusually skilled at taking high-concept science, such as string theory, and making it intelligible to the lay person. He shares his wisdom this month as part of the Linus Pauling Memorial Lecture series sponsored by the Institute of Science, Engineering and Public Policy.

Describe a typical crowd at one of your lectures. Believe it or not, it’s mostly regular people who don’t have any formal training in science. It’s inspiring: When people get a chance to talk about ideas like time, black holes or the Big Bang, they get really fired up.

As an actor, you’ve had cameos in everything from The Last Mimzy, where you portrayed an Intel scientist, to Frequency, a time-travel story in which you played a dramatically older version of yourself. Frequency was scary. I had to age, so I wore prosthetics. [To fit me for them], they buried me alive in plaster and I started freaking out. I felt like I couldn’t breathe. I just remember somebody holding my hand and telling me, “It’ll be alright.”

You still teach at Columbia University. Do you ever get any hormonal young punks trying to show you up in class? No. But mainly because I’m teaching majors in physics and math who, on average, have fewer hormones.

Do you have physics groupies? People have been struggling with these ideas for thousands of years—not just intellectually, but emotionally—so yeah, there are familiar faces. They have their own theories and want me to help think them through. On one level, that’s great. Still, it’s hard to respond to hundreds of different theories; some people have trouble understanding that.