In our February cover story, “Before the Big Bang,” author and Time magazine senior writer Michael D. Lemonick explores the idea that the Big Bang was triggered when our three-dimensional universe collided into another three-dimensional universe hidden in higher dimensions. Rather than being the beginning of everything, the Big Bang was but one cataclysm in a long, perhaps infinite cycle of collisions and cosmic rebirths.
Needless to say, we got a large number of amazed and curious letters. Through our new Web-exclusive feature, the Expert Forum, readers had a chance to pose their questions directly to Lemonick, whose answers to about two dozen of these queries appear below. “I'm impressed with how Discover readers absorbed a mind-bending concept and came back with so many thoughtful and challenging questions,” he says.
Donna Frisoli, age 47, Maine
Question: Were you saying that the universes are flat? I’m a little confused about that because if that is the case, I would find that hard to believe, as this universe is made up of spheres. Am I way off base?
Lemonick: It’s not surprising that you’re confused—I get that way too when the dimensions start to multiply. When astrophysicists say the universe is flat, they’re talking about a three-dimensional version of flatness. It’s analogous to the flatness we see in a two-dimensional sheet of paper, say, but it’s not something you can easily visualize. But just as you can draw a circle on a flat piece of paper, you can put spherical planets, stars, and such into a three-dimensional flat universe.