[ntp:questions] Leap second functional question

David Woolley david at ex.djwhome.demon.co.uk.invalid
Fri Feb 22 07:50:22 UTC 2008

Unruh wrote:

>> High precision orbital dynamics, such as the JPL's DE405, are done in 
>> Barycentric Dynamic Time, which runs at a different rate than TAI, but
>> is "TAI like" in that it has no leap seconds.
> It does? The second was defined to make the speed of light a consant. Are
> you saying they use a system in which the speed of light changes from time
> to time? That sounds horrible. 

I believe he is talking about the general relativity correction.  Even 
GPS would be wildly wrong if you used the earthbound definition of a 
second for the clocks in the satellites.

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