Cesium, iodine from the Chernobyl reactor accident went around the world many times and everyone on the Earth has a piece of Chernobyl in their bodies, but it's very tiny - too small to cause much damage.

Hover boards, unfortunately, currently violate the laws of physics. Supermagnets exist, but they have to be cooled to near absolute zero, and they are extremely expensive. So Michael J. Fox's hover boards are not possible until we invent room temperature super conductors.

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 used to watch the old 'Flash Gordon' series on TV, and it was thrilling to rocket to the planet Mongo every week. But after a while, I figured out that although Flash got the girl and all the accolades, it was really Dr. Zarkov who made the series work. Without Dr. Zarkov, there could be no Flash Gordon.

We can summarize electricity, magnetism and gravity into equations one inch long, and that's the power of field theory. And so I said to myself: I will create a field theory of strings. And when I did it one day, it was incredible, realizing that on a sheet of paper I can write down an equation which summarized almost all physical knowledge.

It is often stated that of all the theories proposed in this century, the silliest is quantum theory. In fact, some say that the only thing that quantum theory has going for it is that it is unquestionably correct.

A force field is basically an invisible shield. You push a button and all of a sudden a bubble forms around you which is impenetrable. It can stop bullets, it can stop ray gun blasts and we realized force fields are actually a little bit difficult to create.