Probability we're the only intelligent life ever? Really low, say astronomers.

Astronomers revised the half-century old Drake equation, which attempts to calculate the probability of the existence of advanced alien civilizations, to determine whether any such civilizations have existed at any point in the history of the universe.

They found that the chances that a human civilization evolved on Earth and nowhere else in the universe are less than about one in 10 billion trillion....
http://www.csmonitor.com/Science/2016/0501/Are-we-the-only-intelligent-life-in-cosmos-Probably-not-say-astronomers