英国著名物理学家史蒂芬•霍金近日发出警告，称外星生物可能真的存在，但是人类与他们接触可能会带来毁灭性的后果
在“探索”频道新近推出的纪录片《与霍金一起了解宇宙》中，霍金指出外星生物在消耗尽自己星球上的资源后便会乘坐大型飞船到他们能够到达的星球掠夺资源，并将那里开拓成为他们的殖民地；如果有外星生物到访地球，那将会像当年意大利航海家哥伦布登陆美洲大陆一样，最后给人类带来毁灭性的灾难。
Aliens may exist but mankind should avoid contact with them as the consequences could be devastating, British scientist Stephen Hawking warned Sunday.
"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," said the astrophysicist in a new television series, according to British media reports.
The programs depict an imagined universe featuring alien life forms in huge spaceships on the hunt for resources after draining their own planet dry.
"Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they can reach," warned Hawking.
The doomsday scenario is suggested in the series "Into the Universe with Stephen Hawking" on the Discovery Channel, which began airing in the United States on Sunday.
On the probability of alien life existing, he says: "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."
Glowing squid-like creatures, herds of herbivores that can hang onto a cliff face and bright yellow predators that kill their prey with stinging tails are among the creatures that stalk the scientist's fantastical cosmos.
Mankind has already made a number of attempts to contact extraterrestrial civilizations.
In 2008, American space agency NASA beamed the Beatles song "Across the Universe" into deep space to send a message of peace to any alien that happens to be in the region of Polaris -- also known as the North Star -- in 2439.
But the history of humanity's efforts to contact aliens stretches back some years.
The US probes Pioneer 10 and 11 were launched in 1972 and 1973 bearing plaques of a naked man and woman and symbols seeking to convey the positions of the Earth and the Sun.
Voyager 1 and 2, launched in 1977, each carry a gold-plated copper phonogram disk with recordings of sounds and images on Earth.
