unruh wrote:
On 2011-09-21, David Woolley <[email protected]> wrote:
unruh wrote:
On 2011-09-21, David Woolley <[email protected]> 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
North points.
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