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BigDon
2014-Oct-15, 04:51 PM
for the Moon to rise and set full every night over your location? (While still maintaining a twenty-four hour day)


From a survival horror game my friends and I are playing. Takes place in New Mexico in "post-Apocalyptia ".

I tried to picture in my head some arrangement and couldn't do it

I'm thinking a simple answer isn't in the works and there's going to be the need to differ to an actual orbital mechanic.

Though any process quick enough to do it in the life time of a person would more than likely pull the oceans clear out of their basins, in my opinion.

NEOWatcher
2014-Oct-15, 04:58 PM
Earth-Sun Lagrange point 2.
Although; that would put it 4 times farther away.

Amber Robot
2014-Oct-15, 05:52 PM
Earth-Sun Lagrange point 2.
Although; that would put it 4 times farther away.

L2 is not a stable position. You could put the Moon there, but it wouldn't stay there.

antoniseb
2014-Oct-15, 06:38 PM
It might stay there long enough for the story to play out.

mkline55
2014-Oct-15, 06:38 PM
Do you just want equal orbital periods for the Earth and the Moon? It shouldn't be too difficult to calculate the distance the moon would have to be from earth to have an orbital period equal to one year. Alternatively, you could move the Earth closer to the Sun so Earth's orbital period is about 28 days. You could also have many combinations where Earth's orbital period around the sun equals the Moon's orbital period around Earth. You could also have the Moon orbit the Earth twice a day, so it was always exactly opposite the Sun at moon rise and again at moon set.

NEOWatcher
2014-Oct-15, 06:58 PM
Do you just want equal orbital periods for the Earth and the Moon? It shouldn't be too difficult to calculate the distance the moon would have to be from earth to have an orbital period equal to one year.
Technically, that would be 0 unless you are talking about different eccentricities.
That's why I said L2. Let the combined gravity pull you into an Earth equivalent orbit around the sun. (L2 in particular for the "full moon")


Alternatively, you could move the Earth closer to the Sun so Earth's orbital period is about 28 days. You could also have many combinations where Earth's orbital period around the sun equals the Moon's orbital period around Earth.
How does that work?


You could also have the Moon orbit the Earth twice a day, so it was always exactly opposite the Sun at moon rise and again at moon set.
That would limit the full moons to a particular longitude.

mkline55
2014-Oct-15, 07:17 PM
Technically, that would be 0 unless you are talking about different eccentricities.
So you claim the moon would take exactly one year to orbit the Earth if the distance between Earth and Moon is zero? How does that work?


How does that work?
How do you want it to work? Move Earth inside Mercury's orbit? Maybe you'd prefer to lengthen the day by spinning the Earth a little slower?


That would limit the full moons to a particular longitude.
Maybe you missed that part of the original question.


. . . for the Moon to rise and set full every night over your location?
Or did you assume your location changes every night?

BigDon
2014-Oct-15, 07:51 PM
Thank you for the inputs all.

On the Steam gaming network it's the game 7 Days To Die.

During the day the zombies are Romero-esque shuffle-butt zombies, (except the *darn* dogs), but at night they run and will mob you in short order unless you're well hidden or barricaded. The game actually makes you afraid of night coming on.

You spend a lot of time watching the Moon go down so it got me wondering. Thank you! :)

John Mendenhall
2014-Oct-16, 12:52 AM
Only one thing that has bothered me after dark since about age 14 was walking back from the East End in a long Apollo after curfew.

(That's 'Olongapo', Don. Since no one else will get it anyhow let it stand.)

BigDon
2014-Oct-16, 10:41 AM
Mr. Mendenhall, I have an "amateur appendectomy" scar from doing just that.

O'po was and still is a dangerous party town.

Did you hear the latest? An entire fleet is being held in port at the moment because some Marine didn't know enough to check his "date" for excessive larynx.

Freakin' jarheads. Ah well, if they were smarter we wouldn't have 'em.

NEOWatcher
2014-Oct-16, 11:47 AM
So you claim the moon would take exactly one year to orbit the Earth if the distance between Earth and Moon is zero? How does that work?
Other than L2, I don't see how it can work any other way.
My question is how you can put them in the same orbit.


How do you want it to work? Move Earth inside Mercury's orbit? Maybe you'd prefer to lengthen the day by spinning the Earth a little slower?
I prefer nothing. You stated it can be done, and I want to know how.



Maybe you missed that part of the original question.
No, I'm clarifying.

Jeff Root
2014-Oct-18, 08:11 AM
Alternatively, you could move the Earth closer to the Sun so
Earth's orbital period is about 28 days. You could also have
many combinations where Earth's orbital period around the
sun equals the Moon's orbital period around Earth.
How does that work?
He's just saying that instead of moving the Moon farther
away from Earth so that it is at the Sun-Earth L2 point,
move the Earth and Moon closer to the Sun so that the
Sun-Earth L2 point is where the Moon is. Or compromise
and move both partway.




You could also have the Moon orbit the Earth twice a day,
so it was always exactly opposite the Sun at moon rise and
again at moon set.
That would limit the full moons to a particular longitude.
It seems like an adequate solution.

-- Jeff, in Minneapolis

NEOWatcher
2014-Oct-20, 11:53 AM
He's just saying that instead of moving the Moon farther
away from Earth so that it is at the Sun-Earth L2 point,
move the Earth and Moon closer to the Sun so that the
Sun-Earth L2 point is where the Moon is. Or compromise
and move both partway.
That's still L2 like I originally stated, just a different location. Besides, he also said a 28 day orbit which seemed to be significant for some reason. That would put the orbit far inside of Mercury's.



It seems like an adequate solution.
I never said it wasn't