3 ms·
could someone please explain this, i wish i could say i get it, but i am so confused. i don't understand, are they not using gps just to synchronize the clocks
by macaroni 15y ago
could someone please explain this, i wish i could say i get it, but i am so confused. i don't understand, are they not using gps just to synchronize the clocks on both ends? what does it matter if in orbit the distance seems shorter or longer if observed (viewed) from the satellites (is this what they are saying?)?
- themgt 15y agoThe simplest way I can (try to) understand it is to imagine a line drawn between CERN and Gran Sasso. From the GPS point of view(consider the GPS satellites as stationary), this line is moving approximately in a Gran Sasso->CERN direction, and is therefore very slightly shorter than what the researchers on the ground calculated
- podperson 15y agoLet's suppose you're trying to time a 100 yard dash based on sound. Someone fires a gun, the race starts, and when the first runner crosses the finish line another gun is fired, you determine the elapsed time. There are obvious things to correct for -- e.g. if you're standing at the finish line the sound from the finish line will take 1/3 of a second (roughly) to get to you, so you need to adjust your calculation. Now suppose that you are standing off on a barge during the race. You know the distance to the start and finish lines but ignored the drift of the barge because you figured it was insignificant. We're talking 60 nanoseconds. The satellites are moving at tens of thousands of miles an hour.
- podperson 15y ago"the sound from the _start_ line" :-)