[time-nuts] jovian and saturnian day length
William H. Fite
omniryx at gmail.com
Sun Jul 10 09:57:44 EDT 2016
Here's some insight into measurement of jovian rotation back in the good
old days. A wee bit more sophisticated than looking at the Great Red Spot.
Gardner, FF & Shain, CA (1958). Further Observations of Radio Emission from
the Planet Jupiter. Australian Journal of Physics 11(1) 55-69.
On Saturday, July 9, 2016, jimlux <jimlux at earthlink.net> wrote:
> They measure some presumed solid(ish) center.
> If the magnetic field axis and the rotation axis are displaced, you can
> measure when the magnetic field goes by. Or by radio sources.
> Jupiter day length at the poles is slightly longer than day length at
> equator, but it's about 1% 9 hr 56 min vs 9 hr 50 min.
> I figure the Jupiter day length (which has been given as about 10 hours
> for a very long time, certainly before we sent spacecraft nearby) is
> probably from visual observation of the Great Red Spot. You can easily see
> it move in a not very big telescope over the course of a night.
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