海角大神

The world is more closely connected than you think.

Hungarian writer Frigyes Karinthy first introduced the idea in 1929 that听people are separated by According to the six degrees of separation theory, each person on Earth could be connected to any other person by tracing a path through six acquaintances. In other words, any one of us is just six people away from President Obama, Pope Francis 鈥� or even evasive Islamic State terror leader Abu Bakr al-Baghdadi.

But social media is shrinking the world and it听turns out we're now closer to 3.57 degrees of separation, according to Facebook.

鈥淚n honor of Friends Day, we鈥檝e crunched the Facebook friend graph and determined that the number is actually 3.57,鈥� . 鈥淓ach person in the world (at least among the 1.59 billion people active on Facebook) is connected to every other person by an average of three and a half other people.鈥�

In the US, Americans are even more closely connected 鈥� 3.46 degrees compared to 3.75 worldwide 鈥� according to the research.

In fact, even as the world population has ballooned, the degrees of separation between its 7 billion inhabitants has been shrinking over time as more of the world goes online. A Facebook study commissioned in 2011, when about a tenth of the world's population was on the social network, concluded there were 3.74 degrees of separation. In 2008 the number was 4.28.

鈥淥ur collective 鈥榙egrees of separation鈥� have shrunk over the past five years,鈥� Facebook鈥檚 data team writes. 鈥淚n 2011, researchers at Cornell, the Universit脿 degli Studi di Milano, and Facebook computed the average across the 721 million people using the site then, and found that it was 3.74. Now, with twice as many people using the site, we鈥檝e grown more interconnected, thus shortening the distance between any two people in the world.鈥�

, Facebook includes a calculator that computes how close you are from everyone else. Facebook CEO Mark Zuckerberg has 3.17 degrees of separation, while COO Sheryl Sandberg is at 2.92.

To find these numbers, and an average degree of separation, the Facebook team used algorithms to find the approximate number of people within 1, 2, 3, and so on, hops away from a source.

Facebook offered this simple scenario to illustrate the process. "Imagine a person with 100 friends. If each of his friends also has 100 friends, then the number of friends-of-friends will be 10,000. If each of those friends-of-friends also has 100 friends then the number of friends-of-friends-of-friends will be 1,000,000."

Facebook's research听confirms what a听听辞蹿听听听have found: That is, largely thanks to the Internet and social media, it turns out the world is getting smaller even as it grows.

Of course, there's also research to suggest that Facebook friends are not all meaningful relationships.

British anthropologist Robin Dunbar theorized in the early 1990s that a human being can have up to 150 meaningful relationships, which became known as "Dunbar's number."

As 海角大神's Jeff Ward-Bailey reported, a听new study听by Mr. Dunbar confirms that听the average Facebook user has about 150 friends on the social network, but that鈥檚 not the same thing as having 150 friends in real life.听

that on average, only about 15 Facebook friends can be counted on to lend emotional support in difficult times, and only five Facebook friends could be counted as 鈥渃lose鈥� friends.

That doesn鈥檛 mean that Facebook friendships are worthless, though. Mr. Dunbar found that social networks allow people to maintain relationships even when they鈥檙e busy or live far away from their friends. Facebook can be a good way to make sure that friendships don鈥檛 fade away, the study concedes.

Even though Facebook and other networks make it much easier to communicate with friends, there鈥檚 no real correlation between the number of Facebook friends someone has and the number of offline friends they have. At best, Dunbar finds, social networks allow people to cultivate casual friendships, which don鈥檛 require much emotional investment. Think of people you鈥檇 be glad to chat with at a party, but wouldn鈥檛 turn to for support in a crisis.