On Tue, Nov 23, 2010 at 1:14 PM, Jon Elson <el...@pico-systems.com> wrote:
> The GPS system has atomic clocks accurate to some insane level like one > second in 10,000 years. They have to periodically adjust the clocks for > relativistic > effects. NIST runs the master clocks for the system from Boulder, and keeps improving them. The most recent generation uses single Aluminum ion, and is accurate to 1s in over 3 billion years. This is so sensitive that when the latest clock was being tested it showed a discrepancy which at first got everyone worried, but then turned out to be the result of a 17 cm elevation difference between it and the previous clock used for reference. The clock instrument scientists wrote a nice Science paper on general relativistic effects of Earth gravitational field: http://www.sciencemag.org/content/329/5999/1630.abstract http://tf.boulder.nist.gov/general/pdf/2447.pdf ------------------------------------------------------------------------------ Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! Tap into the largest installed PC base & get more eyes on your game by optimizing for Intel(R) Graphics Technology. Get started today with the Intel(R) Software Partner Program. Five $500 cash prizes are up for grabs. http://p.sf.net/sfu/intelisp-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
