Kevin Bacon, the actor. Kevin Winter/Getty Images

“ Six Degrees of Separation.” It was one of those catch phrases of the last 20 years.  It started with a 1967 study, which led to John Guare’s 1990 play (a Pulitzer Prize winner), which led to a 1993 film (Stockard Channing was nominated for best actress), which led to “ Six Degrees of Kevin Bacon,” the trivia game.

But are we really separated by six degrees? A team of scientists at Facebook and the University of Milan has now culled through masses of data and concluded it’s really 4.74.

The original idea, as laid out by the social psychologist Stanley Milgram, was that each of us is a friend of a friend of a friend of a friend (I won’t repeat it six times) of everyone else on Earth, no matter how remote, and if we work at it we’ll realize that we know someone … who knows someone else … who knows someone else — and it will never take more than six steps to get to anyone else. It’s a small world after all — a giant social network.

Well, Facebook conveniently has become a giant social network, with more than 800 million active members — terrific for testing Milgram’s idea in the digital age. Lars Backstrom and some fellow computer scientists devised a formula to see how closely we’re all connected through Facebook “friends,” and found the world has become smaller since Milgram’s experiment, which was done with postcards.

“While 99.6 percent of all pairs of users are connected by paths with 5 degrees (6 hops),” Backstrom wrote on a Facebook blog, “92 percent are connected by only four degrees (5 hops). And as Facebook has grown over the years, representing an ever larger fraction of the global population, it has become steadily more connected. The average distance in 2008 was 5.28 hops, while now it is 4.74.

“Thus, when considering even the most distant Facebook user in the Siberian tundra or the Peruvian rainforest,” he said, “a friend of your friend probably knows a friend of their friend.”

So let’s see. Do you know Kevin Bacon? I don’t, but a friend here knows his agent (that means three degrees between us), and I’ve sent an email.

Bacon, in good humor about having a name associated with “six degrees,” runs a charity called SixDegrees.org. Nice name.  Will he change it?