Sunset at the South pole

The dark sector camera says it all -

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

Being among people in the 21st century who are simply uninterested in the surface rotation behind that event is quite an experience, after all, all daily sunsets arise from a surface rotation so no real effort is required to apply the separate rotation to the annual event at the South pole at the March Equinox.

It is not everyday that people wake up to celebrate a dawn or twilight with a new surface rotation behind it but if people think about it for a while they will adapt to that perspective.

The insight in front of readers is not meant as a taunt as the most precious thing people have is to value the people who actually live in this era and who have the power to contribute in meaningful ways to a more intimate relationship between the individual and the Universal. There are those who wish to live on past glories even if their agendas were always unproductive and downright disruptive to begin with however there is room for even these people to change their tune.

Instead of thinking of the North/South poles in terms of an axis of rotation, they provide a window into the orbital behavior of the Earth and the surface rotation which will cause polar sunrise and sunset in a number of days..

In theoretical terms the opportunity provided by this perspective is so vast that it is difficult to maintain any sort of neat historical and technical outlines. With the emergence of the heliocentric system one of the first things that also emerged was a look at what caused the Earth to move around the Sun. Up until the late 17th century the idea had surfaced that the rotation of a larger object imparted orbital motion on smaller objects surrounding them -

"The Sun and the Earth rotate on their own axes...The purpose of this
motion is to confer motion on the planets located around them;on the
six primary planets in the case of the Sun,and on the moon in the case
of the Earth.On the other hand the moon does not rotate on the axis of
its own body,as its spots prove " Kepler

Even from first impressions which cause the surface of the Earth to rotate unevenly to the central Sun coincident to an orbital circuit (as per polar sunrise/sunset), that input would appear to have a galactic orbital signature influencing the annual orbital motion of the Earth around the Sun. It is something that can be noticed from the Fomalhaut system which provides a default orbital geometry invariably described as 'offset' rather than elliptical -

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

It is unlikely that theorists can work with the solar system's galactic orbital inputs into annual planetary trajectories given that they have trouble with even basic cause and effect such as the cause behind polar sunset in a few days -

http://icestories.exploratorium.edu/...3/sunset_2.jpg

On Wednesday, March 16, 2016 at 10:33:35 AM UTC, oriel36 wrote:
"On the other hand the moon does not rotate on the axis of
its own body,as its spots prove " Kepler

An observer on the moon experiences sunrise and sunset once as the Moon orbits the Earth, which as you have explained many times (for the Earth) is a result of a surface rotation, showing that the Moon rotates once per orbit of the Earth, and that Kepler was wrong.

It is something that can be noticed from the Fomalhaut system which provides a default orbital geometry invariably described as 'offset' rather than elliptical -

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

Galactic who now? I didn't know you had a crackpot theory about Fomalhaut. I will have a look in the archives to see if I can make out what you have misunderstood this time...

It is one of those rare times in my life and in the existence of this forum when I can take things easy and allow observers to adjust to the spectacle where the Sun will appear at the North polar latitude and disappear from the Southern point due to a surface rotation arising from the orbital behavior of the Earth -

https://www.youtube.com/watch?v=okw6Mu3mxdM

To discuss and even enjoy speculating about orbital components requires acceptance of the dual surface rotations of the Earth and to grant other eras their due for at least trying.

All dawns bring with them a promise of a new day with productive work to do and in 4 days on the Equinox, when the Sun will have been absent for 6 months it will appear and remain for 6 months at the Northern polar point. It is a once in a year spectacle at each polar point and a once in a lifetime insight for those who want to be astronomers in all its facets.

On Wednesday, March 16, 2016 at 1:31:01 PM UTC, wrote:
On Wednesday, March 16, 2016 at 10:33:35 AM UTC, oriel36 wrote:
"On the other hand the moon does not rotate on the axis of
its own body,as its spots prove " Kepler

An observer on the moon experiences sunrise and sunset once as the Moon orbits the Earth, which as you have explained many times (for the Earth) is a result of a surface rotation, showing that the Moon rotates once per orbit of the Earth, and that Kepler was wrong.


It really isn't possible to descend to an intellectual level where the lunar day/night cycle needs to be explained using its orbital motion around the Earth -

http://homepages.umflint.edu/~mistar...moonphases.jpg


We have the vantage point of the lunar day/night cycle from its orbital position either between the Earth and the Sun or most distant from the central Sun. The oldest known lunar calendar from Knowth recognizes that the moon becomes lost behind the glare of the Sun for a number of days while I am here in the 21st century explaining to a damaged individual that the lunar day/night cycle is observed in terms of its phases,orbital motion and position.

Sunrise and sunset at the Southern polar latitude is from a separate rotation to daily rotation -

http://www.timeanddate.com/sun/antarctica/south-pole

The radius between North pole and circle of illumination is now approach zero and after the Equinox the circumference where the Sun remains in view each 24 hours expands until it reaches its maximum circumference known as the Arctic circle.

The proliferation of celestial sphere descriptions of the Equinox using a tilting circle of illumination and the motion of the Sun North and South of the planet's daily rotational Equator where the circle of illumination pivots off the Equator is both recent and disturbing -

http://apod.nasa.gov/apod/ap140319.html

On the other hand there is the gentle appearance of the Sun at the North pole dictated by the orbital surface rotation behind it -

https://www.youtube.com/watch?v=okw6Mu3mxdM

There is no need to be thugs anymore unless people take perverse satisfaction in vandalizing astronomy and its work principles which include two separate day/night cycles arising from separate rotational causes. Somebody has to feel that both and sunrise and a sunset is a consequence of a turning Earth and in this way feel human on account of recognizing our planet's motions.

On Wednesday, March 16, 2016 at 4:33:35 AM UTC-6, oriel36 wrote:
It is something that can be noticed from the Fomalhaut system which provides
a default orbital geometry invariably described as 'offset' rather than
elliptical -

As Fomalhaut B has a large difference between its perihelion and aphelion, its
orbit definitely exhibits the nature of orbits set down by Kepler - an ellipse,
with the primary, in this case the star Fomalhaut, at one focus.

It is _low_ eccentricity orbits, like that of the Earth around the Sun, that
are almost indistinguishable from a circle with the Sun's position slightly
offset from the centre (the equant of Ptolemy and all that).

It is unlikely that theorists can work with the solar system's galactic
orbital inputs into annual planetary trajectories

As the motion of the Sun in the galaxy is common to it and the planets which
orbit it, it does not add anything to our understanding of how the planets
orbit the Sun.

The galactic motion of the Solar System is taken into account _when it
matters_, such as in the study of the proper motions of other stars in our sky.

John Savard

On Wednesday, March 16, 2016 at 7:31:01 AM UTC-6, wrote:
On Wednesday, March 16, 2016 at 10:33:35 AM UTC, oriel36 wrote:

"On the other hand the moon does not rotate on the axis of
its own body,as its spots prove " Kepler

An observer on the moon experiences sunrise and sunset once as the Moon orbits
the Earth, which as you have explained many times (for the Earth) is a result
of a surface rotation, showing that the Moon rotates once per orbit of the
Earth, and that Kepler was wrong.

Kepler, at least, had the intelligence to know exactly what he was saying.

As you and I both well know, the Moon has surface features that show that one
side of the Moon always faces the Earth.

Kepler - like Oriel - followed the naive convention that such a situation meant
that the Moon does not rotate. This is, in fact, quite a normal default
position for people to take. Just as most people will say in ordinary
conversation that the Earth rotates on its axis once every 24 hours so that we
can have days and nights.

Practicing scientists today, though, find this naive view inadequate.

The Equation of Time in the case of the Earth, and libration in longitude in the case of the Moon, show that neither the Earth nor the Moon has its rotation, as it were, "nailed down" to its orbital motion.

Tidal forces may keep the _period_ of the Moon's rotation equal to that of its orbit, but in the short run, the Moon rotates freely, and at a uniform rate, while its elliptical orbit makes its angular revolution non-uniform. Acknowledging, therefore, that the Moon does rotate lets us see that its rotation is uniform - without any back-and-forth wiggling that libration seems to imply.

That back and forth wiggling is just the difference between the Moon's uniform rotation and the nature of an elliptical and inclined orbital motion.

For Kepler to adhere to the naive view because it wasn't inadequate for his
purposes doesn't make him wrong.

If Oriel didn't take it upon himself to claim that today's practicing
astronomers _are_ wrong, in taking a more subtle and sophisticated view of the
matter as is appropriate for their purposes, I wouldn't be as critical of his
views either.

As I've noted, when I went to school, I had seen a table of the Solar System
that gave the length of the day on Earth as 23 hours and 56 minutes. That *was*
just wrong. And highly confusing.

But when I saw that the length of the day on Mercury was given as 88 days -
instead of forever - this was back when people thought Mercury always turned
one face towards the Sun, the way the Moon does towards Earth - I was able to
figure out what was going on.

The term "day", without qualification, means the synodic day, not the sidereal
day, and for a junior high school textbook to brutally confuse young students
in this manner is to be criticized. A reaction to that sort of thing is
warranted - unfortunately, Oriel is not the man to carry it out. He is rooted
in the naive perspective, which is not without value, but he lacks the
understanding to realize that the sophisticated perspective also has its place.

John Savard

On Thursday, March 17, 2016 at 3:12:27 PM UTC-7, Quadibloc wrote:

The term "day", without qualification, means the synodic day, not the sidereal
day, and for a junior high school textbook to brutally confuse young students
in this manner is to be criticized. A reaction to that sort of thing is
warranted - unfortunately, Oriel is not the man to carry it out. He is rooted
in the naive perspective, which is not without value, but he lacks the
understanding to realize that the sophisticated perspective also has its place.

Gerald, of course, has no talent for perspective whatsoever, and he has admitted to this more than once over the years. The poor fellow is doomed to fail without this very important gift, so sad for him...

In a few days there is this wonderful dawn at the North pole that happens once each year as the Sun comes into view after being absent for 6 months while at the other pole the Sun vanishes from sight -

https://www.youtube.com/watch?v=okw6Mu3mxdM

I am not interested in the utter hatred for the rotational cause of polar sunrise, what I am interested in is the teamwork necessary to explain the observation by using lessons learned from daily rotation and the appearance of the Sun each day.

I went out early this morning and watched the Sun come into view down by sea level where neolithic astronomers once marked the Equinox and that reward is something money cannot buy. I honor these ancient people by adding to their recognition of orbital points by taking account of polar dawn and its cause arising from the motion of the Earth around the Sun and even if nobody else cares to look at the time lapse at the South pole in the YouTube website, it will always happen twice a year at either poles.