Brief Answers to the Big Questions

by Stephen Hawking

When we see the Earth from space, we see ourselves as a whole. We see the unity, and not the divisions. It is such a simple image with a compelling message; one planet, one human race.

After my expectations had been reduced to zero, every new day became a bonus, and I began to appreciate everything I did have. While there’s life, there is hope.

I have been enormously privileged, through my work, in being able to contribute to our understanding of the universe. But it would be an empty universe indeed if it were not for the people I love, and who love me. Without them, the wonder of it all would be lost on me.

Be brave, be curious, be determined, overcome the odds. It can be done.

Einstein realised something quite extraordinary: that two of the main ingredients needed to make a universe – mass and energy – are basically the same thing, two sides of the same coin if you like. His famous equation E = mc2 simply means that mass can be thought of as a kind of energy, and vice versa. So instead of three ingredients, we can now say that the universe has just two: energy and space.

I am sure that during this century people will discover how to modify both intelligence and instincts like aggression. Laws will probably be passed against genetic engineering with humans. But some people won’t be able to resist the temptation to improve human characteristics, such as size of memory, resistance to disease and length of life. Once such superhumans appear, there are going to be major political problems with the unimproved humans, who won’t be able to compete. Presumably, they will die out, or become unimportant. Instead, there will be a race of self-designing beings, who are improving themselves at an ever-increasing rate.

long-distance space travel will be difficult for chemically based life forms – like us – based on DNA. The natural lifetime for such beings is short compared with the travel time. According to the theory of relativity, nothing can travel faster than light, so a round trip from us to the nearest star would take at least eight years, and to the centre of the galaxy about 50,000 years.

At the moment computers have an advantage of speed, but they show no sign of intelligence. This is not surprising because our present computers are less complex than the brain of an earthworm, a species not noted for its intellectual powers. But computers roughly obey a version of Moore’s Law, which says that their speed and complexity double every eighteen months. It is one of these exponential growths that clearly cannot continue indefinitely, and indeed it has already begun to slow. However, the rapid pace of improvement will probably continue until computers have a similar complexity to the human brain.