Page last updated at 09:35 GMT, Sunday, 25 April 2010 10:35 UK

Stephen Hawking warns over making contact with aliens

Stephen Hawking
Mr Hawking says it is 'perfectly rational' to believe in aliens

Aliens almost certainly exist but humans should avoid making contact, Professor Stephen Hawking has warned.

In a series for the Discovery Channel the renowned astrophysicist said it was "perfectly rational" to assume intelligent life exists elsewhere.

But he warned that aliens might simply raid Earth for resources, then move on.

"If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans," he said.

Prof Hawking thinks that, rather than actively trying to communicate with extra-terrestrials, humans should do everything possible to avoid contact.

He explained: "We only have to look at ourselves to see how intelligent life might develop into something we wouldn't want to meet."

The real challenge is to work out what aliens might actually be like
Stephen Hawking

In the past, probes have been sent into space with engravings of human beings on board and diagrams showing the location of our planet.

Radio beams have been fired into space in the hope of reaching alien civilisations.

Prof Hawking said: "To my mathematical brain, the numbers alone make thinking about aliens perfectly rational.

"The real challenge is to work out what aliens might actually be like."

The programme envisages numerous alien species including two-legged herbivores and yellow, lizard-like predators.

But Prof Hawking conceded most life elsewhere in the universe is likely to consist of simple microbes.

I believe that it is inevitable that different forms of life exist within our universe

In the recent BBC series Wonders of the Solar System, Professor Brian Cox, a physicist from the University of Manchester, also suggested life may exist elsewhere within our solar system.

He said organisms could be present under the ice sheet that envelops Europa, one of Jupiter's moons.

Professor Cox added: "Closer to home, the evidence that life could exist on Mars is growing.

"We will only know for sure when the next generation of spacecraft, fine-tuned to search for life, are launched to the moons of Jupiter and the arid plains of Mars in the coming decades."

Print Sponsor

Number of alien worlds quantified
05 Feb 09 |  Science & Environment
Odds on finding aliens 'too low'
17 Apr 08 |  Norfolk

The BBC is not responsible for the content of external internet sites

Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit


Sign in

BBC navigation

Copyright © 2015 BBC. The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.

Americas Africa Europe Middle East South Asia Asia Pacific