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Katie Freese is a professor of physics at the University of Michigan, and the associate director of the Michigan Center for Theoretical Physics. Her work deals with a wide variety[…]

“It is really a high density situation that we call the big bang, but there is really no explosion,” says Freese. “There is no ‘bang.’ There is no singular point.”

Question: Does it make sense to ask what preceded the Big rnBang?
rn

Katie Freese: I think people have the misconception that rnthe big bang is the universe starting from a point.  In fact, it is veryrn different from that.  Probably you know that the Universe is expanding,rn so if we go backwards in time then you can watch the Universe contract rnas you go backwards in time.  So for example, if you took a tabletop rnthen any two points would get closer together, but the points that are rnway far apart if you had…  Let’s say it’s an infinite tabletop, so as rnthese points get closer and closer together you still have a tabletop rnthat is infinite in extent.  It’s not like everything comes into one rnpoint, but eventually you reach such a high density.  Things are so rncompact and right on top of each other that we lose our description.  rnPhysics fails.  That is what the big bang is, so it’s actually we would rnneed to have a theory of quantum mechanics and gravity simultaneously torn be able to discuss physics going backwards in time any further, so it rnis really a high density situation that we call the big bang, but there rnis really no explosion.  There is no bang.  There is no singular point. rn But so yes, it does make sense to ask well what happens when you reach rnthat density and that is what people are trying to do in theories of rnquantum gravity such as string theory or well some of the cosmology thatrn I’ve done also is in the context of brains where our observable rnuniverse is living on a three dimensional surface in a higher rndimensional universe and there could be other brains out there and how rnthese brains intersect one another and their motions and so on has rnbeen…  So there are different avenues to try to push back our level of rnknowledge and they are very active, but very difficult.

Everythingrn was more dense and then there is a certain point where… which we call rnthe big bang and it’s from that point forward that we start our clocks, rnso that’s…  And then so and we say the universe is 13.7 billion years rnold is relative to that very high density situation.

Recorded May 7, 2010
Interviewed by David Hirschman