Add Yahoo as a preferred source to see more of our stories on Google. "If you found out we weren't alone, if someone showed you, proved it to you, would that frighten you?" the official logline reads.

The first unmistakable signal from another intelligence would rank alongside fire and writing in the story of our species, yet a growing group of researchers warns that such a moment might arrive not ...

Sagan's team created the greatest puzzle of all time, which you can only solve if your species understands the basic nature of the universe.