On Thursday, July 21, 2016 at 11:45:01 AM UTC+1, Mike Collins wrote:
Gerald Kelleher wrote:
The reflected light of a lunar day/night cycle within the polar day/night
cycle doesn't require anything more than a brief consideration of the
moon's motion around the Earth each month and it really is enchanting -

http://www.usap.gov/videoclipsandmaps/spwebcam.cfm

To see something happening in real time is truly special and an
indication of whether people are comfortable living with 21st century
imaging and the conclusions and insights drawn from these observations.

On any given day there are motions to account for and especially the
motion going on beneath the feet of humanity and separately the planet's
orbital motion through space and around the Sun. In this clear perceptual
air where experiences of the day/night cycle and the seasonal cycle make
sense, the insights start to flow once more and break up the self-imposed
celestial sphere shell humanity acquired from people a number of centuries ago.



https://youtu.be/MXxfEOsMtoo

A video showing how the South Pole rotates in a 24 hour day.

The only valid view at the South pole is that the Sun comes into view at the March Equinox and is absent from view after the September Equinox representing the distinct polar day/night cycle and the surface rotation behind it..

The insight is for those who have already accepted that the daily rotational speeds diminish from a maximum at the Equator to zero at the poles with the speeds contained within the 24 hour system and Lat/Long system which celestial sphere cultists seem intent on ignoring.

A little over a mile from the North and South poles and the daily rotational speed at the surface is 1/4 mile per hour while, as a function of its orbital motion, the same location turns in a circle to the central Sun at an average rate of 30 miles per day with greater or lesser values depending on the orbital speed of the Earth. This variation shows up at lower latitudes where it combines with constant daily rotation.

It doesn't matter to me what qualification a person has, common sense dictates that the ground beneath your feet has a specific daily rotational speed and that changes as you move towards the Equator or towards the North and South poles in your respective hemisphere. The maximum speed any person experiences as a function of daily rotation is 1037.5 miles per hour at the Equator insofar as the geographical separation represented by that value is 15 degrees of longitude and 1 hour's timekeeping difference.

Thank you for the time lapse of the moon as it makes a circuit of the Earth and don't forget that the major insight is the continuous reflected light as the moon passes across the polar surface in its monthly orbit of the Earth. Do not, I repeat, do not bundle lunar motion with circumpolar motion otherwise it wastes an entirely wonderful perspective of the monthly lunar orbit and the unique view at the poles.