## Six Degrees of separation

Na Eun Seo

Blog Post #1

09/20/12

“The Six Degrees of Kevin Bacon” insists that any two people on Earth are about six acquaintances apart from each other. Kevin Bacon is an actor who came up with this theory and what he is trying to say eventually out of it is the small world phenomenon. These days, the world is becoming smaller and smaller and even in our daily lives we experience that two of our acquaintances that we would never expect to know each other are actually friends. As newer and faster contacting methods are being developed, such as Facebook and Twitter, the range of mutual friends between  people is getting wider. The first time that “The Six Degrees of Kevin Bacon” surfaced was 1994. And the author of this article is saying that we know every other person on Earth not even taking six steps but 4.74 steps, therefore, the world got even smaller.

In class, we defined a component as “an internally connected group of nodes, with no edges in or out.” And further, we learned what a graph is: a structure consisting of a set of nodes, some pairs of which are linked by edges. The Global Friendship network is one of the examples of a graph. We consider all the people on Earth as nodes and friendships as edges. The professor posted a question asking if all the nodes in the network are connected to each other. He answered that there is a very slight chance that two giant groups exist in this world because it is almost impossible that there is not any mutuals between two groups because both of them contain many people, which means wider range of connections. He added that the possibility could have existed at some point in history. However, the professor suggested it is possible that a small separate component exists. The component might have been isolated from the rest of the world for a long time or the component might contain one single person who does not have any friends at all. Therefore, what the author and Kevin Bacon insisted might not be always right. We should also consider that the number 4.74 is just an average, so that not every other person could know each other in 4.74 steps. There is always an exception, in this case, a completely isolated group which has no social connection at all with other groups in the world, such as a tribe which has been isolated from the rest of the world ever since its establishment in history.