[ntp:questions] Google and leap seconds
david at ex.djwhome.demon.invalid
Thu Sep 22 07:26:00 UTC 2011
> On 2011-09-21, David Woolley <david at ex.djwhome.demon.invalid> wrote:
>> unruh wrote:
>>> On 2011-09-21, David Woolley <david at ex.djwhome.demon.invalid> wrote:
>>>> Richard B. Gilbert wrote:
>>>>> It's unfortunate that the earth DOES NOT rotate exactly 360 degrees in
>>>>> exactly 24.000000000000 hours. This bit of poor design causes all sorts
>>>> It's nothing like it. It out by approximately 1 degree a day!
>>> well, not if you define the rotation with respect to the "mean sun"
>>> rather than the stars. Then it is only out by a few PPB.
>> It makes a big difference for GPS, though. I believe their orbital
>> period is half a sidereal day, not 12 hours or even 43200 TAI seconds.
> The orbit is far faster than that. You mean the period of the orbit (not
> in the orbit) as seen from earth.
I don't understand.
The orbit plane is fixed relative to the fixed stars, so, for the orbit
to cover the same ground each time, it has to have a period that exactly
divides the sidereal day. The period is between successive maximum
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