# Thoery of Relativity and the Moon Landing **URL:** \ **Category:** Factual Questions\ **Created:** [April 18, 2008, 1:59pm UTC](https://boards.straightdope.com/t/thoery-of-relativity-and-the-moon-landing/445886 "2008-04-18T13:59:19Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [April 18, 2008, 10:37pm UTC](https://boards.straightdope.com/t/thoery-of-relativity-and-the-moon-landing/445886/21 "2008-04-18T22:37:03Z")
Do GPS satellites compensate for Special and General Relativity? I’ve heard that somewhere, probably not true, most likely an urban legend. (I’m tempted to say they need a treadmill, but I won’t) 😃 ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [April 18, 2008, 10:46pm UTC](https://boards.straightdope.com/t/thoery-of-relativity-and-the-moon-landing/445886/22 "2008-04-18T22:46:00Z")
Wait. What’s the difference between a T-H-O-E-R-Y, like the OP is asking about and a T-H-E-O-R-Y? I’m familiar with the latter, but not the former. ---
**Author:** ![Byzz](https://avatars.discourse-cdn.com/v4/letter/b/90ced4/32.png) [@Byzz](https://boards.straightdope.com/u/Byzz)\ **Post date:** [April 19, 2008, 2:48am UTC](https://boards.straightdope.com/t/thoery-of-relativity-and-the-moon-landing/445886/23 "2008-04-19T02:48:41Z")
[QUOTE=DSYoungEsq] Do GPS satellites compensate for Special and General Relativity? I’ve heard that somewhere, probably not true, most likely an urban legend. [/QUOTE] There may be some truth to it. It seems like I heard something like that fairly recently. ---
**Author:** ![The\_Them](https://avatars.discourse-cdn.com/v4/letter/t/898d66/32.png) [@The\_Them](https://boards.straightdope.com/u/The_Them)\ **Post date:** [April 19, 2008, 3:36am UTC](https://boards.straightdope.com/t/thoery-of-relativity-and-the-moon-landing/445886/24 "2008-04-19T03:36:11Z")
Once, I read this thing about Apollo 16, where they had an atomic clock onboard, and it registered that the astronauts had spent milliseconds more on the mission than they would have had they stayed home. The Punchline: “They were not paid any overtime.” Ok, quote might not be perfectly word-for-word. ---
**Author:** ![Peter\_Morris](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peter_morris/32/359_2.png) [@Peter\_Morris](https://boards.straightdope.com/u/Peter_Morris)\ **Post date:** [April 19, 2008, 3:42am UTC](https://boards.straightdope.com/t/thoery-of-relativity-and-the-moon-landing/445886/25 "2008-04-19T03:42:02Z")
Wouldn’t it have been the other way around? A clock under acceleration runs more slowly, so the astronauts spent a few microseconds \*less \* time than the ground crew. ---
**Author:** ![Rhubarb](https://avatars.discourse-cdn.com/v4/letter/r/59ef9b/32.png) [@Rhubarb](https://boards.straightdope.com/u/Rhubarb)\ **Post date:** [April 19, 2008, 3:50am UTC](https://boards.straightdope.com/t/thoery-of-relativity-and-the-moon-landing/445886/26 "2008-04-19T03:50:36Z")
[QUOTE=Peter Morris] Wouldn’t it have been the other way around? A clock under acceleration runs more slowly, so the astronauts spent a few microseconds \*less \* time than the ground crew. [/QUOTE] The majority of the trip was not made under acceleration, while terrestrial based clocks are under constant (1g) acceleration.\* \*That’s why the GPS system is related specially to Einstein. I know it’s true cuz I heard it on the innernets. ---
**Author:** ![Peter\_Morris](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peter_morris/32/359_2.png) [@Peter\_Morris](https://boards.straightdope.com/u/Peter_Morris)\ **Post date:** [April 19, 2008, 4:14am UTC](https://boards.straightdope.com/t/thoery-of-relativity-and-the-moon-landing/445886/27 "2008-04-19T04:14:58Z")
Fair enough. Ignorance fought. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [April 19, 2008, 6:59pm UTC](https://boards.straightdope.com/t/thoery-of-relativity-and-the-moon-landing/445886/28 "2008-04-19T18:59:34Z")
It isn’t that hard to get relativistic effects that are measureable. Here is a fellow who did it on a family vacation with the kids: [http://leapsecond.com/great2005/index.htm](http://leapsecond.com/great2005/index.htm) ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [April 20, 2008, 2:13am UTC](https://boards.straightdope.com/t/thoery-of-relativity-and-the-moon-landing/445886/29 "2008-04-20T02:13:15Z")
[QUOTE=Napier] It isn’t that hard to get relativistic effects that are measureable. Here is a fellow who did it on a family vacation with the kids: > **[Project GREAT: General Relativity Einstein/Essen Anniversary Test](http://leapsecond.com/great2005/index.htm)** [/QUOTE] So his GPS was off? I’m confused. [Previous page](https://boards.straightdope.com/t/thoery-of-relativity-and-the-moon-landing/445886.md?page=1)