These articles were taken out of The
Summary of the World
If we could shrink the Earth's population to a village of precisely 100 people, with all existing human ratios remaining the same, it would look like this:
MATHEMATICS: Random Shortcuts to a Smaller World
Small world, isn't it? Indeed, mathematicians have estimated that everyone on the planet may be connected to everyone else by about six degrees of attachment. If you and I are friends, that's a first-degree connection; if we don't know each other, but your friend is a friend of mine, that's a second-degree. And so forth. At the sixth-degree, we're all linked. Networks of this "small world" kind lie somewhere between completely random patterns and entirely regular ones in which, for example, each neighbor can talk only to his next-door neighbors, but not directly to anyone down the block. Neither random nor perfectly regular networks allow you to send a message in the shortest time.
But adding only a very few random links to a regular network, two researchers from Cornell University report in the June 4 issue of Nature, drastically shortens the average path length between distant points, turning it into a "small world" system that allows information - or disease - to spread with surprising speed, just as it does in human society. So it might make sense to redesign some of our essential but highly regular systems, such as phone networks, to include a few random connections. It is "alarming," the theorists write, "how few shortcuts are needed to make the world small."