| MadSci Network: Astronomy |
Dear Mr. Vargha,
The eccentricity of the moon's orbit is 0.0549. That of the earth is 0.017 and of Jupiter, 0.048. On Oct. 16, 2001, the distance from moon to Jupiter was 4.88656 A.U. or, at 1.495978707E8 km per A.U.
The mean distance of the moon from earth is 384,500 km. Ignoring the fact that our Earth/moon system actually orbits around the barycenter of the two planets, about 3000 miles beneath the surface of the earth, that means the moon's distance from Jupiter varies from its orbit by 3.845E5 / 7.31018971E8 = 0.0526 %.
See the Observer's Handbook, published annually by the Royal Astronomical Society of Canada and available from Sky Publishing, www.Skypub.com on the internet for more information. You can make similar calculations to determine the percent of variation in the Moon-Jupiter distance caused by the eccentricities of the planets' orbits.
I estimated any answer to your query using planetarium software: SkyChart III is available as shareware at www.southernstars.com on the internet. Setting my location on the moon on Oct. 16, 2001, opening an information box on Jupiter and running the animation one week into the future per jump, I found the following close approaches. Download the shareware and try it!
Date: Distance in A.U.
Jan 29/2003: 4.32996
Mar 3/2004: 4.42298
I let the program run for a while...
Sep 22/2010: 395171
Jim Foerch
James C. Veen Observatory
Lowell, Michigan
USA
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