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Gravitational Time Dialation

  1. Jun 18, 2008 #1
    Exactly how much does earth's time dialation decrease with distance from the surface?
    I know that it's way to small to ever notice and probably even mesure with today's instruments, but i'm trying to calculate how many billionths or trillionths [or less] of a second a clock might run faster if it was only about 15 feet off the ground.
  2. jcsd
  3. Jun 18, 2008 #2
    Actually it was measure back in the earlu 60s if a famous experiment. It was done at Harvard University by Pound and Rebka.

  4. Jun 18, 2008 #3
    really? that low? cool. you wouldn't happen to know how much it was...or where i could search to find it? i've been working out my own problems but seeing as i havn't even had high school physics yet, i'm not sure if it's anywhere near right.

    I found somewhere where somebody at 1340 feet gained 22 nanoseconds.
    so i did 1340:22= 15:x and x=4.6
    so i put down ground time=1second and 15foottime=1second+4.6 nanoseconds.

    what i'm realy looking for in my end result is how long it would take you [how many LIFETIMES!!] to catch up to your twin who was born two hours before you if you hovered 15 feet in the air.

    so i found that there are 7.2x10^12 nanoseconds in two hours and i divided it by 4[number of nanoseconds gained per ground second] multiplyed by a billion to get seconds. divided by 60, 60, 24, and 365 to get 5,549,213,597,158 years to gain two hours.

    i know that's a bit confusing...i apologize. is this completely wrong?
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