P.C. Shannon

This is the first leap year we've had in eight years. There wasn't a February 29th in 2000 because century years where the century number is divisible by four aren't leap years. So the last time that happened was way back in 1600. The year is most easily approximated as being 365.25 days long, but obviously that's not exact, so we're constantly having to make minor adjustments. Most of us never notice expect for the scientists who keep really accurate clocks, like the atomic clocks run by the government or those aboard GPS satellites. Even these two systems can't completely agree on what time it is and can differ by 10 or 20 milliseconds. Trivial to most of us, but this does present problems for systems that rely on precise timing, like long range fiber optic communications links. Or airliners, which use GPS, and ground-based air traffic control systems, which use the atomic clocks.