Will the Moon's far side face the earth?

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mopc
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Will the Moon's far side face the earth?

Post #1by mopc » 12.09.2009, 00:27

I was fiddling with Celestia just now and I synch orbited the Moon with the Earth in the foreground. Speeding up a few thousand years, I noticed the Earth left the foreground and went behind the camera, at about the 5000. This means what is now the far side of the Moon will become the near side millenia from now. Or is Celestia wrong? I was doing the same thing with a moon of Uranus, Umbriel, and in 70,000 years the same happened. Is Celestia right about these moons not being 100% tidally locked to their planets?

asteroid
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Re: Will the Moon's far side face the earth?

Post #2by asteroid » 12.09.2009, 02:25

I'm going to venture a guess and say it's a bug/glitch. I'll be interested in seeing what the pros say when they chime in.

[strike] I'm having a hard time visualizing exactly what you did. Can you provide a bit more details (bookmark?) [/strike]
nm. I just did the reverse. Orbited the moon to the far side. Turned around to look at Earth but still orbit synced on the moon (Y). Fast forwarding time did exactly what you described by 2200 something.

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mopc
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Re: Will the Moon's far side face the earth?

Post #3by mopc » 12.09.2009, 06:10

No, here I only get the far side become the near side by the 6th millenium. See picture (thats the year 5394):
Image

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selden
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Re: Will the Moon's far side face the earth?

Post #4by selden » 12.09.2009, 11:53

I agree that it's a bug in Celestia.
I've moved this thread to the Bugs forum.

The precision VSOP87 CustomOrbits and IAU CustomRotations used to specify the positions and orientations of solar system objects are good for only about +/- 2000 years from now.

It'd be nice if dates outside that range didn't produce such wrong results for the moon outside that range, though.
Selden

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John Van Vliet
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Re: Will the Moon's far side face the earth?

Post #5by John Van Vliet » 04.10.2009, 04:52

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