A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Amateur Astronomy
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Orbital traits of Earth vs Moon



 
 
Thread Tools Display Modes
  #1  
Old July 24th 18, 09:50 AM posted to sci.astro.amateur
Gerald Kelleher
external usenet poster
 
Posts: 1,551
Default Orbital traits of Earth vs Moon

http://i.imgur.com/fB9jSdy.gifv

The image above is meant to convey a 'rotating moon' but really only displays an orbiting satellite, in this case the LRO.

The traditional narrative is that people argue over whether the Moon rotates or not however the real substance, at least for genuine researchers, is how the Moon behaves differently from the Earth as each travels around their parent central object.

The idea that the Moon also spins as it orbits the Earth is due to a misreading of the awkward phrasing in Kepler's Somnium, this issue has been covered so many times that there is no need to repeat it however the preponderance of the notion is obstructing the appreciation that the Earth actually turns once to the Sun as a function of its orbital motion and pronounced in isolation at the North and South poles which experience a single day/night cycle each orbit as a result of the planet's orbital trait.

So, the point of departure for all issues involved is that as the moon travels around the Earth it does not display all sides of its surface to the central Earth while the Earth traveling around the Sun shows two distinct rotations f the entire surface to the central Sun.

  #2  
Old July 24th 18, 05:27 PM posted to sci.astro.amateur
Quadibloc
external usenet poster
 
Posts: 7,018
Default Orbital traits of Earth vs Moon

On Tuesday, July 24, 2018 at 2:50:39 AM UTC-6, Gerald Kelleher wrote:

The idea that the Moon also spins as it orbits the Earth is due to a misreading
of the awkward phrasing in Kepler's Somnium,


No, it is not due to *reading* anything. That the Moon spins as it orbits the
Earth can be determined by direct observation.

The Earth orbits the Sun, and the Moon orbits the Earth. As the Moon always
keeps one side facing the Earth, an observer on the Moon would experience
*stellar circumpolar motion*. So the Moon does rotate if we take always pointing
in one direction in relation to the fixed stars as not rotating.

But why would we do this?

Because we also directly observe that although the Moon always keeps one face to
the Earth, it also moves a bit from side to side - the phenomenon known as
libration.

And the libration is precisely what one would expect from the Moon rotating at a
uniform rate, but having an _elliptical_ orbit around the Earth.

John Savard
  #3  
Old July 25th 18, 02:17 AM posted to sci.astro.amateur
palsing[_2_]
external usenet poster
 
Posts: 3,068
Default Orbital traits of Earth vs Moon

On Tuesday, July 24, 2018 at 1:50:39 AM UTC-7, Gerald Kelleher wrote:

... So, the point of departure for all issues involved is that as the moon travels around the Earth it does not display all sides of its surface to the central Earth while the Earth traveling around the Sun shows two distinct rotations f the entire surface to the central Sun.


This is because the moon is tidally coupled to the Earth. Read this...

http://www.pas.rochester.edu/~blackm...104/tidal.html

.... where we learn... "... the fact that the rotational period of the Moon and the orbital period of the Earth-Moon system are of the same length is not an accident. Presumably this was not always true, but over billions of years the tidal coupling of the Earth and the Moon has led to this synchronization. In the case of the Earth-Moon system the synchronization is not yet complete. The Earth is slowly decreasing its rotational period and eventually the Earth and Moon will have exactly the same rotational period, and these will also exactly equal the orbital period. "

Isn't that interesting? This is especially good news for us amateur astronomers because we could then move to the hemisphere on Earth that will never see the moon all, and can, therefore, observe every clear night of the year and not have that pesky bright moon cluttering up the night sky half the time.

Isn't it great to learn something new that you didn't know before, Gerald? Obviously, you had no clue before, but now you do!

  #4  
Old July 25th 18, 05:55 AM posted to sci.astro.amateur
Gerald Kelleher
external usenet poster
 
Posts: 1,551
Default Orbital traits of Earth vs Moon

On Wednesday, July 25, 2018 at 2:17:44 AM UTC+1, palsing wrote:



Isn't that interesting? This is especially good news for us amateur astronomers because we could then move to the hemisphere on Earth that will never see the moon all, and can, therefore, observe every clear night of the year and not have that pesky bright moon cluttering up the night sky half the time.



In the wider world there is no longer any fear discussing the orbital motion of the Moon and its lunar day/night cycle whereas the Earth has two distinct day/night cycles. This is the founding principle of any future discussion so if you want to believe the Moon also spins as it orbits the Earth then be my guest, as it lacks any common sense while for others it is a matter of rational cowardice.

It is impossible to consider the seasons, tides or any cyclical Earth science event without recognising how the Earth turns to its parent star in two distinct ways with particular emphasis on the Polar day/night cycle which up to now has been ignored in terms of cause. It is almost daylight at the South Pole at the moment because of the reflected light of the moon as a consequence of its orbital motion of the Earth -

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

Lots to discuss and nobody to discuss it however you can forget a dead end topic of whether the moon spins or not, that is a Royal Society indulgence that is best left for pseudo-intellectuals.





  #5  
Old July 25th 18, 06:16 AM posted to sci.astro.amateur
palsing[_2_]
external usenet poster
 
Posts: 3,068
Default Orbital traits of Earth vs Moon

On Tuesday, July 24, 2018 at 9:55:18 PM UTC-7, Gerald Kelleher wrote:
On Wednesday, July 25, 2018 at 2:17:44 AM UTC+1, palsing wrote:



Isn't that interesting? This is especially good news for us amateur astronomers because we could then move to the hemisphere on Earth that will never see the moon all, and can, therefore, observe every clear night of the year and not have that pesky bright moon cluttering up the night sky half the time.


... if you want to believe the Moon also spins as it orbits the Earth then be my guest, as it lacks any common sense while for others it is a matter of rational cowardice.


So, once again you have failed to learn something new and yet again steadfastly refuse to believe the overwhelming evidence presented. Why am I not surprised? After all, you have been completely unteachable for a very long time!

From virtually every other body in the universe (other than the Earth, due to the aforementioned tidal coupling), assuming that they had the wherewithal to make the observation, the moon would be seen to rotate... just like every other body in the solar system would seem to rotate. EVERYTHING rotates with respect to other bodies, even when they present the same face to a single body.
  #6  
Old July 25th 18, 06:27 AM posted to sci.astro.amateur
Gerald Kelleher
external usenet poster
 
Posts: 1,551
Default Orbital traits of Earth vs Moon

On Wednesday, July 25, 2018 at 6:16:28 AM UTC+1, palsing wrote:
On Tuesday, July 24, 2018 at 9:55:18 PM UTC-7, Gerald Kelleher wrote:
On Wednesday, July 25, 2018 at 2:17:44 AM UTC+1, palsing wrote:



Isn't that interesting? This is especially good news for us amateur astronomers because we could then move to the hemisphere on Earth that will never see the moon all, and can, therefore, observe every clear night of the year and not have that pesky bright moon cluttering up the night sky half the time.


... if you want to believe the Moon also spins as it orbits the Earth then be my guest, as it lacks any common sense while for others it is a matter of rational cowardice.


So, once again you have failed to learn something new and yet again steadfastly refuse to believe the overwhelming evidence presented. Why am I not surprised? After all, you have been completely unteachable for a very long time!

From virtually every other body in the universe (other than the Earth, due to the aforementioned tidal coupling), assuming that they had the wherewithal to make the observation, the moon would be seen to rotate... just like every other body in the solar system would seem to rotate. EVERYTHING rotates with respect to other bodies, even when they present the same face to a single body.


The North and South Poles which represent points on the Earth's surface, where net daily rotation is zero, experiences a single day/night cycle with sunrise/sunset on the Equinoxes. The fact is that when daily rotation and all its effects are subtracted, the planet still turns once to the Sun over the course of an orbit and in this case parallel to the orbital plane.

The title of this thread is not only a comparison of orbital traits between the Moon and the Earth, it is also incorporates the cause of the lunar day/night cycle as an orbital cause and likewise the Polar day/night cycle on Earth also as an orbital cause.

From experience and observation, many people in this space age have adopted a common sense approach and have moved on but unfortunately haven't yet adapted to the Earth/Moon comparisons which offer so much creative and productive research.



 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Proving the Earth's orbital motion. Gerald Kelleher Amateur Astronomy 7 April 5th 18 04:38 PM
The Earth's orbital speed from day to day oriel36[_2_] Amateur Astronomy 6 November 2nd 11 08:03 PM
Sub-Orbital Earth Transits David Spain[_2_] Technology 26 December 30th 09 12:13 PM
Earth's orbital path oriel36 Amateur Astronomy 0 February 4th 07 08:05 PM
Earth Co-orbital Asteroid 2003 YN-107 Thomas Lee Elifritz Policy 0 June 13th 06 05:48 PM


All times are GMT +1. The time now is 03:17 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright 2004-2024 SpaceBanter.com.
The comments are property of their posters.