Sun-Earth-Moon Gravity

Any object can orbit any other object in an infinite number of orbits, so the moon can orbit the sun at the current distance and the earth can orbit the sun at the same distance -- the formula for the gravitational attraction between the sun and the moon or the sun and the earth only tells you what the force holding them IN the orbit is.F_IN = Gravitational force = GmM/R^{^2}The equilibrium of an orbit is established by the force holding the objects OUT from the center, and this is based on obital velocity:F_OUT = Centripetal force = ~mV^{^2}/R
(as a first approximation especially where m << M)In a circular orbit this is simple, in an elliptical orbit it gets a little more complicated, but it is easy to see that

• if F_IN > F_OUT that the object will be pulled in, and
• if F_OUT > F_IN that the object will tend to drift out, AND
• that an object in an elliptical orbit will oscillate between these two conditions

So the question is NOT how big the forces are but whether they BALANCE for the orbit(s) in question.From
Page not found: The Worlds of David Darling
For a circular orbits where F_IN = F_OUT, and where m is closer to M, a more accurate formula for orbital velocity is given:V = {G(M+m)/R}^{^1/2}And using this as a simple approximation we can then compare the orbital velocities for the moon in orbit around the sun (neglecting the earth), for the earth in orbit around the sun (neglecting the moon), and for the {earth\moon} system in orbit around the sun.Prediction: the calculated velocities will be closest to the actual orbital velocity with the {earth\moon} system.Enjoy.

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we are limited in our ability to understand
by our ability to understand

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RebelAAmericanOZen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

Imaginary?http://www1.jsc.nasa.gov/er/seh/feather.htmlvideo of the drop
http://www1.jsc.nasa.gov/er/seh/feather.avi Well christians are always telling us we're fallen ... Enjoy.Edited by RAZD, : added last, title

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Join the effort to unravel {AIDS/HIV} {Protenes} and {Cancer} with Team EvC! (click)

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we are limited in our ability to understand
by our ability to understand

​

RebelAAmericanOZen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.