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.

In science, nothing is ever 100% proven.

Already from your own cells scientists can grow skin, cartilage, noses, blood vessels, bladders and windpipes. In the future, scientists will grow more complex organs, like livers and kidneys. The phrase 'organ failure' will disappear.

In string theory, all particles are vibrations on a tiny rubber band; physics is the harmonies on the string; chemistry is the melodies we play on vibrating strings; the universe is a symphony of strings, and the 'Mind of God' is cosmic music resonating in 11-dimensional hyperspace.

I have nothing against investment banking, but it's like massaging money rather than creating money. If you're in physics, you create inventions, you create lasers, you create transistors, computers, GPS.

One in 200 stars has habitable Earth-like planets surrounding it - in the galaxy, half a billion stars have Earth-like planets going around them - that's huge, half a billion. So when we look at the night sky, it makes sense that someone is looking back at us.

One day I went up to my mom and I said, 'Mom, can I have permission to build a 2.3-million electron-volt atom smasher - a betatron - in the garage?' And my mom stared at me, and she said, 'Sure. Why not? And don't forget to take out the garbage.'

To me, it is clear that we exist in a plan which is governed by rules that were created, shaped by a universal intelligence and not by chance.

Cancer is like the common cold; there are so many different types. In the future we'll still have cancer, but we'll detect it very, very early, so that it won't kill anybody. We'll zap it at the molecular level decades before it grows into a tumor.

Democracies are slow to anger and hesitant to go to war: Voters don't want to sacrifice their children for the glory of a selfish king.

Some people are a little bit afraid about the future because they see all these gadgets and gizmos coming down the pike and they think they're too old to learn all this new stuff. But eventually they begin to realize, 'Hey, some of this stuff is useful.'

When you come up with a theory, you fall in love with the beauty the simplicity and elegance of it. But then you have to get a sheet of paper and pencil and crack out all the details. Hundreds and hundreds of pages. Because you have to prove it.

One in 200 stars has habitable Earth-like planets surrounding it - in the galaxy, half a billion stars have Earth-like planets going around them - that's huge, half a billion. So when we look at the night sky, it makes sense that someone is looking back at us.

The universe is a symphony of strings, and the mind of God that Einstein eloquently wrote about for thirty years would be cosmic music resonating through eleven-dimensional hyper space.

If I wasn't a professional scientist, I'd be an amateur scientist. But plan B was to go into computers.

So often, science fiction helps to get young people interested in science. That's why I don't mind talking about science fiction. It has a real role to play: to seize the imagination.

I predict that technology will enable people to transmit their neuronal, actual feelings over the Internet.

Sooner or later, we will face a catastrophic threat from space. Of all the possible threats, only a gigantic asteroid hit can destroy the entire planet. If we prepare now, we better our odds of survival. The dinosaurs never knew what hit them.

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.

In Einstein's equation, time is a river. It speeds up, meanders, and slows down. The new wrinkle is that it can have whirlpools and fork into two rivers. So, if the river of time can be bent into a pretzel, create whirlpools and fork into two rivers, then time travel cannot be ruled out.

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

Our grandkids will lead the lives of the gods of mythology. Zeus could think and move objects around. We'll have that power. Venus had a perfect, timeless body. We'll have that, too. Pegasus was a flying horse. We'll be able to modify life in the future.

The job market of the future will consist of those jobs that robots cannot perform. Our blue-collar work is pattern recognition, making sense of what you see. Gardeners will still have jobs because every garden is different. The same goes for construction workers. The losers are white-collar workers, low-level accountants, brokers, and agents.

No one knows when a robot will approach human intelligence, but I suspect it will be late in the 21st century. Will they be dangerous? Possibly. So I suggest we put a chip in their brain to shut them off if they have murderous thoughts.