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The First Known Interstellar Comet



 
 
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  #41  
Old November 2nd 17, 04:09 PM posted to sci.astro.amateur
Gerald Kelleher
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Default The First Known Interstellar Comet

On Thursday, November 2, 2017 at 2:36:11 PM UTC, Chris L Peterson wrote:
On Thu, 2 Nov 2017 07:04:54 -0700 (PDT), Gerald Kelleher
wrote:

When Venus reaches its widest point after it emerges as an evening appearance it will then turn back in front of the Sun and move from left to right until it overtakes us and becomes a morning appearance once more.


What do "left" and "right" mean? If I walk outside today and look up
at the Sun


You look out at the central Sun and stationary Sun and not up. If you can't put the central reference for all motions in correct context and drop up/below or North/South (which are rotational terms) it is impossible to reference orbital motions to either the moving Earth, to the stationary Sun or to the other planets.

I don't blame you, you have a rotating celestial sphere in your head and can't adjust to the recognized motions of Venus and Mercury in their transition from an evening to a morning appearances which is to say from left to right of the Sun as seen from a slower moving Earth as the planet overtakes us or from right to left or a morning to evening appearance as the planet moves behind the Sun -

http://www.popastro.com/images/plane...ary%202012.jpg

Maybe somebody else will explain to you that we see the faster moving Venus and Mercury run their circuits around a stationary Sun much like Jupiter's satellites will move from left to right and then from right to left of their parent planet -

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










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  #42  
Old November 2nd 17, 09:57 PM posted to sci.astro.amateur
Bill[_9_]
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Default The First Known Interstellar Comet

On Thu, 02 Nov 2017 08:36:10 -0600, Chris L Peterson wrote:

On Thu, 2 Nov 2017 07:04:54 -0700 (PDT), Gerald Kelleher
wrote:

When Venus reaches its widest point after it emerges as an evening appearance it will then turn back in front of the Sun and move from left to right until it overtakes us and becomes a morning appearance once more.


What do "left" and "right" mean? If I walk outside today and look up
at the Sun while facing south, Venus will be on its left. If I'm
facing north, Venus will be on its right. It only makes sense to use
these terms when considering very specific viewpoints. In most cases,
they are ambiguous and non-useful. That's why we have astronomical
coordinate systems.


Why, the next thing you'll say is:
Oct. 31 = Dec. 25!
And you'll be absolutely correct.

Sorry, old joke maybe? ;-)

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Email address is a Spam trap.
  #43  
Old November 2nd 17, 10:12 PM posted to sci.astro.amateur
Gerald Kelleher
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Posts: 889
Default The First Known Interstellar Comet

It is always the same when someone comes in and blows themselves up in a thread where things are being worked through.

The transition of Venus from left to right of the Sun is perhaps understood as a rare transit when it overtakes the faster moving Earth -

https://www.youtube.com/watch?v=_7U5VbasKr4&t=117s

During that period the Earth is also heading in the same orbital direction but as it is slower, the faster moving inner planet will eventually appear preceding the Sun or as a dawn appearance.

An extended version of Jupiter's satellites as they move from left to right in front of the planet before moving from right to left behind their central planet eases any difficulty there may be as an analogy -

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

The real innovation is the transition of the background stars from left to right or a transition from an evening to morning appearance as it is this observation that proves the Earth orbits the Sun.



  #44  
Old November 2nd 17, 10:25 PM posted to sci.astro.amateur
Gerald Kelleher
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Posts: 889
Default The First Known Interstellar Comet

Of course the error will be jumped on. Venus overtakes us from left to right and passes from an evening to morning appearance in the same direction as the slower moving Earth -

https://www.youtube.com/watch?v=_7U5VbasKr4

Those who dispute right/ left of the Sun in terms of orbital motions are uninterested and uninteresting. This language will form the basis of a software program outside the present attempt to model observations using a celestial sphere program of which there are many.

Of course left/right is definitive and not arbitrary but at least it is being discussed for a change.
 




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