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Re: [Phys-l] celestial motion




On Aug 23, 2008, at Aug 23(Sat) 5:27 , LaMontagne, Bob wrote:

The sun moves approximately 1 degree / day through the sky.

i.e. against the background of the fixed stars - which we don't see very clearly during the daytime ;-)




Another celestial motion weirdness is that the orbit of our moon is always concave toward the sun.
The moon doesn't 'loop' around the earth in its orbit

it is sometimes said that the earth and our moon are two planets that share the same orbit

'curvature' of an orbit is tied to the acceleration of the object and the moon is always accelerating toward the sun more than it is accelerating toward the earth.