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<DIV>Dear Nainan,</DIV>
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<DIV>You wrote: “<FONT face="Courier New"><EM>Do you really believe in
elliptical/circular/ovoid planetary orbits?”</EM></FONT></DIV>
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<DIV>By definition, an orbit is a closed figure, a cycle path (“orbis” =
circle). This has to to be understood in the relative frame of the attractive
body. But you are right to remind than in the absolute frame, the figure is not
closed, because the attractive body is also moving.</DIV>
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<DIV>I also agree that on the very long term, the orbit is not stable (in the
relative frame of the attractive body): the attracted body will either escape
from or crash on the attractive body.</DIV>
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<DIV>But in the relative frame of the attractive body, the ellipsoïd model is a
better one than the circular model, for example with Mars planet. And the ovoïd
model is a better one than the ellipsoïd model, for example with Mercury
planet.</DIV>
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<DIV>For sure they all are only “models”. If you check my demonstration, you
could note that I use some (justified) simplifications, for example Equation
I.24. The true orbit should be more complex in fact than the ovoïd orbit. Ovoïd
orbit is only a model, but in my opinion a more accurate one than the ellipsoïd
model.</DIV>
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<DIV>I hope I answered to your question.</DIV>
<DIV>Kind regards.</DIV>
<DIV>O. Serret</DIV>
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