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  Mercury - Gemini - Apollo
  Apollo launch windows: Moon at perigee? (Page 3)

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Author Topic:   Apollo launch windows: Moon at perigee?
Jim Behling
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Posts: 587
From: Cape Canaveral, FL
Registered: Mar 2010

posted 09-13-2013 06:54 AM     Click Here to See the Profile for Jim Behling   Click Here to Email Jim Behling     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by moorouge:
...how else was the Apollo 8 'earthrise' photo taken?
Because there is earthrise on every orbit for every spacecraft that orbits the moon. That has nothing to do with being earth or moon framed. See, you are confused.

Glint
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Posts: 762
From: New Windsor, Maryland USA
Registered: Jan 2004

posted 09-13-2013 12:03 PM     Click Here to See the Profile for Glint   Click Here to Email Glint     Edit/Delete Message   Reply w/Quote
quote:
I'm quite happy to believe the Royal Astronomical Society and other professional astronomers that I've consulted.

So, what it comes down to is...an appeal to authority?

Gonzo
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Posts: 416
From: Lansing, MI, USA
Registered: Mar 2012

posted 09-13-2013 02:17 PM     Click Here to See the Profile for Gonzo   Click Here to Email Gonzo     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Glint:
So, what it comes down to is...an appeal to authority?
What it all REALLY comes down to is this - how do you define an orbit? What does it mean to say that [insert thing] "orbits" [insert another thing].

On one hand, to say simply that one thing orbits the other can be accepted on the surface. But I think we all agree that looking at it, there's much more to the question. And that is where we disagree. How do those finer details alter the statement?

So it's not based on some authority saying this or that. It's based on logic, physics and mathematics and how far you want to take the definition of what orbits what - and if that even means anything.

So unless someone can come up with some grand explanation that will please everyone (doubtful), I think this will end up being a "agree to disagree" kind of thing as there are merits to both sides of the discussion.

moorouge
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Posts: 1547
From: U.K.
Registered: Jul 2009

posted 09-13-2013 02:38 PM     Click Here to See the Profile for moorouge   Click Here to Email moorouge     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Jim Behling:
Because there is earthrise on every orbit for every spacecraft that orbits the moon.
Now you really are clutching at straws. Of course earthrise occurs for every orbit of a spacecraft. It also happens for someone standing on the Moon's surface. I merely used it as an example of taking where one centres a perspective of orbiting bodies to point out that one can overcomplicate matters. I thought that was clear in the post.

The debate in this thread is about the nature of the orbit of the Moon round the Sun and its relationship with the Earth's orbit. References to the path of the Sun in the galaxy and the path of the galaxy in the universe are irrelevant in this particular discussion as is the gravitational effect of Aunt Min's starlight pudding.

sev8n
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Posts: 62
From: Dallas TX USA
Registered: Jul 2012

posted 09-13-2013 03:27 PM     Click Here to See the Profile for sev8n     Edit/Delete Message   Reply w/Quote
There seems to be a general misconception that an orbit and a path are the same thing.

An orbit is defined by gravitational forces exerted on the considered object(s).

A path is defined by the chosen frame of reference.

Blackarrow
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Posts: 2091
From: Belfast, United Kingdom
Registered: Feb 2002

posted 09-14-2013 08:41 AM     Click Here to See the Profile for Blackarrow     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by moorouge:
Of course earthrise occurs for every orbit of a spacecraft. It also happens for someone standing on the Moon's surface.

The second of these statements is just plain wrong (except for the very special case of someone standing in the libration zone).

moorouge
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Posts: 1547
From: U.K.
Registered: Jul 2009

posted 09-14-2013 11:32 AM     Click Here to See the Profile for moorouge   Click Here to Email moorouge     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Blackarrow:
The second of these statements is just plain wrong (except for the very special case of someone standing in the libration zone).
Precisely. I wasn't 'plain wrong', just not precise enough. I was thinking of the 'children'.

Blackarrow
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Posts: 2091
From: Belfast, United Kingdom
Registered: Feb 2002

posted 09-14-2013 12:25 PM     Click Here to See the Profile for Blackarrow     Edit/Delete Message   Reply w/Quote
Hmmm... you wriggled out of that quite well, but let's leave it to the stern but fair jury of our peers to determine if you messed up your whole argument, or if you meant the libration zone all along.

spacebrane
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Posts: 51
From: Vale of Paradise, Indiana
Registered: Apr 2005

posted 09-14-2013 05:56 PM     Click Here to See the Profile for spacebrane   Click Here to Email spacebrane     Edit/Delete Message   Reply w/Quote
Reading the round-and-round arguments on this post (pun intended), it's even more amazing that the Apollo program enjoyed the success it did. I wonder if the Apollo mission planners argued as much about physics as some of the posters on this thread. Oh, I hope not.

Thank goodness the guys in The Trench knew what they were doing.

SpaceAholic
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Posts: 3059
From: Sierra Vista, Arizona
Registered: Nov 1999

posted 09-14-2013 06:23 PM     Click Here to See the Profile for SpaceAholic   Click Here to Email SpaceAholic     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Jim Behling:
Because there is earthrise on every orbit for every spacecraft that orbits the moon.
With some exceptions such as polar orbits — LRO for example observes 48 hour periods of uninterrupted line of sight with the Earth roughly every two weeks.

canyon42
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Posts: 186
From: Ohio
Registered: Mar 2006

posted 09-14-2013 07:40 PM     Click Here to See the Profile for canyon42   Click Here to Email canyon42     Edit/Delete Message   Reply w/Quote
This is getting silly. You just can't have it both ways. If the statement "The moon orbits the Earth" is somehow a "lie," then so must be the statement "The Earth orbits the sun." If one is a lie, both must be, because the same complexities lie within each statement.

Moorouge, I'm pretty sure that everyone understands your main point (even though you were just plain wrong about the Earth rising for anyone on the moon's surface). I mean, it's not like you're the first person to ever notice the intricacies of bodies moving in space. However, when the whole question boils down to what frame of reference one defines, then claiming that the observation taken from one frame is "true" while another is a "lie" is your problem. None of them are lies, period, just different ways of defining the situation.

Drop the "lie" nonsense from your contention and I think you'll find that no one is disagreeing with you. Otherwise, you have to accept that saying that the moon orbits the sun is just as much a lie as saying that it orbits the Earth, for the exact same reason. The balance of the moon-Earth system is not at the center of the Earth, but neither is the balance point of the sun-Earth system--or the moon-sun system, for that matter. In each case the balance point lies within the body of the larger object, but in none of them is it at the center.

If you want to claim that NOTHING orbits anything else in the universe, and that any such claim in any situation is a lie, well then, have at it. You just don't get to arbitrarily decide which frame of reference is "true" while declaring that the most commonly used frame is a "lie," though, no matter how many times you keep trying to make the same point over and over--a point that we already UNDERSTAND.

moorouge
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Posts: 1547
From: U.K.
Registered: Jul 2009

posted 09-15-2013 01:41 AM     Click Here to See the Profile for moorouge   Click Here to Email moorouge     Edit/Delete Message   Reply w/Quote
I've never claimed it was a 'lie'. Please go back and read the definition of a 'lie for children'.

YankeeClipper
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Posts: 238
From: Dublin, Ireland
Registered: Mar 2011

posted 09-15-2013 11:53 PM     Click Here to See the Profile for YankeeClipper   Click Here to Email YankeeClipper     Edit/Delete Message   Reply w/Quote
In the 17th Century, the Inquisition dealt with Giordano Bruno and Galileo Galilei by way of threats of imprisonment without trial, weeks of torture on the rack, and burning at the stake.

In the 21st Century, all it took was 3 pages of this argument.

I recant. I recant all my "heretical" beliefs!!

(Frame of reference is an interesting concept. I've met certain individuals who firmly believe that the entire universe revolves around them personally regardless of gravitational centers!)

moorouge
Member

Posts: 1547
From: U.K.
Registered: Jul 2009

posted 09-16-2013 01:39 AM     Click Here to See the Profile for moorouge   Click Here to Email moorouge     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by YankeeClipper:
In the 17th Century, the Inquisition dealt with Giordano Bruno and Galileo Galilei by way of threats of imprisonment without trial, weeks of torture on the rack, and burning at the stake.
Some of the replies in this thread have been 'sheer torture'.

Incidentally, burning at the stake was considered to be a kindness as it saved the condemned soul from eternal damnation.

And another oddball fact - Joan of Arc was not burnt by the English but the French and not for heresy but because she wore trousers.

Blackarrow
Member

Posts: 2091
From: Belfast, United Kingdom
Registered: Feb 2002

posted 09-16-2013 04:32 PM     Click Here to See the Profile for Blackarrow     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by YankeeClipper:
I've met certain individuals who firmly believe that the entire universe revolves around them personally regardless of gravitational centers!
This is complete nonsense. I am quite happy to concede that the entire universe does not revolve around me. It just extends outwards in all directions from the focal point that is me.

Doesn't it?


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