Dennis,-

Yeah, I read that story when I googled "time-nuts". Cool stuff. It got me to wondering: If (as he demonstrated) time dilates with distance from the gravity well of the earth, doesn't that make GPS based reference standards inherently less accurate than earth based ones *on earth*? I'm sure the smart folks worked out some sort of compensation for long-term effects. Perhaps the GPS birds are receiving corrections from a ground station (in which case, calibrating a ground-based oscillator to the bird would make it run faster than it should). Or perhaps the GPS oscillators are running at a slightly slower rate than earth-based ones, technically making them inaccurate at their actual orbit.

Personally, back in the real world of doctor's appointments and bus schedules, my house standard is a wrist-watch that sets itself from the radio signal from Boulder every night. But it was out by an hour this morning, since it was made before the powers that be changed the DST dates, making the automatic DST setting useless. So I had to manually correct the hour. When I set the clocks in my cars and house to DST this morning, I used the watch as a reference and now all my clocks are within 0.5 minutes of that signal, which should get me to work on time tomorrow morning. ;-)