Thread: The awful pivot
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Old September 21st 18, 07:44 AM posted to sci.astro.amateur
Gerald Kelleher
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Default The awful pivot

On Thursday, September 20, 2018 at 11:21:47 PM UTC+1, Mike Collins wrote:
Gerald Kelleher wrote:
The pivoting circle of illumination off the Equator on an Earth with a
zero inclination was something I first saw in Wikipedia 'Seasons' article
and it still remains that way -

https://en.wikipedia.org/wiki/Season

This was extended last year by NASA and the APOD website

https://apod.nasa.gov/apod/ap170319.html


Again and again the explanations now term the Equinox as the Sun
directly over the Equator when the Equator always presents the same
daylight length throughout an orbit.


Another thing which individuals are keen to jump in it that
daylight/darkness is not equal on the Equinox and fiddle about with the
tiny variations while they completely ignore the Polar day/night cycle
where daylight extends beyond 6 months so no, not all parts of the Earth
experience a daylight/darkness symmetry.

The recent uptake of the pivoting circle of illumination explanation is
alarming, even for this mind accustomed to wayward notions of motions,
orientation and so on. Wish I could give people credit for undoing this
mess or better still - working towards explaining the proper mechanisms
for the Equinox and the seasons but unfortunately not again this year or
any other year previously despite the spectacular productive research the
mechanism contains.


On the equator the Sun is only directly overhead on the equinoxes. In the
northern summer the sun is always to the north and in the southern summer
it’s always to the south. At the equinoxes and only at the equinoxes it’s
directly overhead at noon.


http://afewbitsmore.com/img/2015_ecliptic.png

(* The March/September orientations are reversed)

The orbital plane is defined as the broken line and with the Sun at the centre of the solar system and the only permissible motion of the Sun is its actual galactic orbital motion. This is why it is important to switch the explanation of the seasons to the motions and orientations of the Earth insofar as variations in planetary orbital speeds may be influenced by the galactic orbital motion of the Sun but this is set aside for the moment.

Unfortunately there is a white-out at the South Pole presently so Polar sunrise will be obscured by local weather but when the Sun comes into view or basically when the South and North Poles have turned and are at exactly 90 degrees to the Sun/Earth line (defined by the broken line) then this is the Equinox. The awkward and useless 'tilting earth' explanation disappears and the planets two distinct rotations take its place.

Unlike others who come into these threads want to be the best boy in the class, at least you are not afraid of being bullied into silence like others have so credit where it is due. The recent emergence of the pivoting circle of illumination and the planet with a zero inclination should alarm everyone with a shred of common sense and decency so it is these you should be countering and not me -

https://apod.nasa.gov/apod/ap170319.html