Famed theoretical physicist Stephen Hawking will celebrate his 70th birthday on Sunday, January 8. And to mark his birthday, he recently answered questions from listeners of BBC Radio channel 4′s Today show. According to the BBC, “Topics ranged from the origins of the universe to the prospects for extra terrestrial life and the impact on Einstein’s theory of relativity should neutrinos be confirmed to travel faster than light.”

The question that elicited the response about extraterrestrials was submitted by a Twitter user named @CazCarpSnail. The question asked, “What do you think the impact will be on humankind if Kepler 22-b [Earth-like planet found by Nasa's Kepler Space Telescope] does indeed support life?” Hawking responded:

The discovery of intelligent life elsewhere in the Universe would be the biggest scientific discovery ever. But it would be very risky to attempt to communicate with an alien civilization. If aliens decided to visit us then the outcome might be similar to when Europeans arrived in the Americas. That did not turn out well for the Native Americans.

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