Six degrees of Osama bin Laden

The N.S.A.’s Math Problem  by JONATHAN DAVID FARLEY

The National Security Agency’s entire spying program seems to be based on a false assumption: that you can work out who might be a terrorist based on calling patterns. While I agree that anyone calling 1-800-ALQAEDA is probably a terrorist, in less obvious situations guilt by association is not just bad law, it’s bad mathematics, for two reasons.

President Bush is only a few steps away from Osama bin Laden (in the 1970’s he ran a company partly financed by the American representative for one of the Qaeda leader’s brothers). And terrorist hermits like the Unabomber are connected to only a very few people. So much for finding the guilty by association.[…]

A second problem with the spy agency’s apparent methodology lies in the way terrorist groups operate and what scientists call the “strength of weak ties.” […] You might not see your college roommate for 10 years, but if he were to call you up and ask to stay in your apartment, you’d let him. This is the principle under which sleeper cells operate: there is no communication for years. Thus for the most dangerous threats, the links between nodes that the agency is looking for simply might not exist.

A trick of the light

In the wierd spooky realms of quantum physics, it turns out you can play lots of tricks with the speed of light:

Robert W. Boyd, a professor of optics at the University of Rochester … demonstrated an optical fiber — a glass strand that transmits pulses of light — with a couple of odd characteristics:
A pulse of light shot into the fiber departs before it enters.
Within the fiber, the pulse travels backward — and faster than the speed of light.

And no, I don’t understand it either.