إستيفن هـوكنج - جاء الوقت لمغــادرة الأرض

By Dan Satherley

Stephen Hawking, perhaps the world's best-known astrophysicist, says humankind is doomed if it doesn't get off planet Earth – and the sooner the better.

"It will be difficult enough to avoid disaster on planet Earth in the next hundred years, let alone the next thousand, or million," he told website Big Think.

"If we are the only intelligent beings in the galaxy, we should make sure we survive and continue."

In April, however, Mr Hawking warned against making alien contact, the chances of which would increase with interstellar travel. If recent discoveries on Mars are any indication, even travelling within our own solar system could be fraught with unexpected danger.

The A Brief History of Time author guesses most extraterrestrial life will be microbial, or primitive animals, but that advanced lifeforms may be "nomads, looking to conquer and colonise".

"If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn’t turn out very well for the Native Americans."

Despite these concerns, Mr Hawking is adamant it's time to expand.

"Our only chance of long term survival, is not to remain inward looking on planet Earth, but to spread out into space," he says.

"The human race shouldn't have all its eggs in one basket, or on one planet."

But which planet should we move to? The closest star to our own is Proxima Centauri, 4.2 light years away. Voyager, launched in 1977 is expected to be the first human craft to enter interstellar space, but at its current speed – 17km/s – it will take tens of thousands of years to reach it.

There is also no guarantee Proxima Centauri has any orbiting habitable planets.

However, Mr Hawking is a fan of time travel. He believes one day humans will be able to take advantage of faster-than-light technology.

"Time travel was once considered scientific heresy, and I used to avoid talking about it for fear of being labelled a crank," he said earlier this year, adding that now he's not so cautious.

3 News