The energy necessary to create a wormhole or to wrap time into nuts is incredible. It's not for us. It's maybe for our descendants who have mastered the energy of this technology. So if one day, somebody knocks on your door and claims to be your great great great great granddaughter, don't slam the door.

We physicists don't like to admit it, but some of us are closet science fiction fans. We hate to admit it because it sounds undignified. But when we were children, that's when we got interested in science, for a lot of us.

They basically ask their engineers to volunteer some probability figures, then they take the average. This is not science. This is voodoo.

Technologies that may be realized in centuries or millennium include: warp drive, traveling faster than the speed of light, parallel universes; are there other parallel dimensions and parallel realities? Time travel that we mentioned and going to the stars.

It would take a civilization far more advanced than ours, unbelievably advanced, to begin to manipulate negative energy to create gateways to the past. But if you could obtain large quantities of negative energy-and that's a big "IF" - then you could create a time machine that apparently obeys Einstein's equation and perhaps the laws of quantum theory.

Even if we mortgage the next 100 years of generations of human beings, we would not have enough energy to build a Death Star.

I'm a physicist, and we have something called Moore's Law, which says computer power doubles every 18 months. So every Christmas, we more or less assume that our toys and appliances are more or less twice as powerful as the previous Christmas.