I wanted to go to a session on
“Multiverses, Dark Energy, and Physics as an Environmental Science”
that included talks from Lawrence Krauss, Andrei Linde, and Leonard
Susskind. When I got there though, people were sitting on the floor and there was a line out the door. Who'd have thunk? But here's what
I was able to glean from the hallway outside:
- Recent data from the Boomerang experiment, a balloon-borne telescope launched from Antarctica to study cosmic microwave background radiation, has shown that the universe appears to be flat.
- Since a higher-density universe would be convex, and a lower-density universe would be concave, it's pretty improbable that the density of our universe would be just right, making it flat. Hence the term “Goldilocks universe."
- As it happens though, the math doesn't work out. All the matter in the universe, including even weird dark matter, makes up only about 30 percent of this critical density. To balance the equation, some physicists have proposed that empty space has energy—a vacuum maybe—that drives cosmic expansion.
- On the other hand, the anthropic principal holds that the universe looks like it does only because we're here to observe it (as Buckaroo Banzai said: “Wherever you go, there you are.”) It's a nifty bit of hand-waving that critics refer to as “the A-word.”
At that point I got tired of craning my neck and I left. But suffice it to say that inflationary theory opens up the possibility of multiple universes, each with different properties. Maybe in one of them I got a seat.
