On Sat, Dec 16, 2017 at 5:59 PM, <[email protected]> wrote: >> >> A curved line from one wall to the other is longer than a straight line >> , >> and yet when you measure the time it takes for light to do this with >> your very accurate clock you notice its exactly the same. You already know >> the measured speed of light never changes so >> if something is moving at the same speed and moves a greater distance in >> the same number of clock ticks then >> you'd have to conclude that being accelerated makes your clock run slow. >> > > > > Since a clock in the gravity field measures less elapsed time, the number > of ticks in your example cannot be identical in those two cases.
A clock at 1g produces ticks at a slower rate but the laser beam from one side on the elevator cab to the other is curved and thus longer . A clock at zero g will produce ticks at a faster rate but the laser beam from one side on the elevator cab to the other is straight and thus shorter 5. So when observers in both cabs count the number of ticks it takes for the Laser to go from one side of the cab to the other then get the same number, >> >> >> T >> he >> GPS >> satellite is moving very fast so due to Special Relativity the >> satellite's clock will LOSE 7210 nanoseconds a day, but the satellite's >> clock is in a weaker gravitational field than the clock >> on the ground >> because it is further from the Earth's center, so due to GENERAL >> RELATIVITY the clock will GAIN 45850 nanoseconds a day. Taking these 2 >> factors into account the satellite's clocks gains 45850 −7210 = 38,640 >> nanoseconds a day relative to >> a >> clock >> on the ground. If this were not taken into account the GPS system would >> drift off by 6 miles a day. >> >> > > > There's a problem applying SR in this situation because neither the ground > or orbiting clock is an inertial frame. > That's why general relativity must also we used. Two different thing must be taken into account for the GPS to be accurate, the clock on the earth and the clock in space are in gravitational fields of different strengths AND the clocks are in motion relative to each other. John K Clark -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
