Taking a light hearted tone during the proceedings - with frequent references to popular culture - Hawking said: "I don't believe science fiction like Star Trek, where people are essentially the same 400 years in the future."

Hawking said that new technology - such as artificial intelligence - would not be the only change over the next 1000 years. Human beings, said Hawking, were also likely to evolve, either due to environmental factors or genetic engineering.

His lecture touched on topics as diverse as subatomic physics and the mathematical probability that the Chicago Cubs would win the world series in baseball.

After the talk, questions were opened up to a world-wide audience via the Internet. Even astronaut Andrew Thomas, currently orbiting in the Mir space station, appeared briefly. The final question - posed by Al Gore - asked Hawking his viewpoint on an antigravity effect causing the universe's expansion rate to increase. Hawking took a cautious position and said such an effect must be very small if the current observations are to believed.