If the internet has taught us anything, there are plenty of people who absolutely freak out about aliens. That club includes one of the smartest people alive: Stephen Hawking, who has been anything but shy about expressing strong fears that a hostile alien civilization could one day blow up humanity to smithereens.

What gives? Hawking is part of a growing number of scientists who think intelligent extraterrestrial life isn’t just real, but probably a lot more common than we might assume. But unlike many of his more optimistic scientist-celebrity colleagues, Hawking thinks contact with aliens would probably spell doom for our species. In fact, he advocates slinking back into the background and keeping our presence in the universe shrouded until we have a better understanding of how to deal with alien affairs.

Eternally optimistic Seth Shostak has the opposite point of view. The director for the Center of SETI Research at the SETI Institute in Mountain View, California published an opinion piece in The Guardian on Tuesday rebutting Hawking’s ideas about hostile aliens, (most recently expressed in the new film Stephen Hawking’s Favourite Places).

"Eternally optimistic?" Or, dangerously naive? To read more, click here.