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(Ah, yes, pedantry. It has its own gravity. You can't tell me it's not a force. I can't resist its pull.) It wouldn't be an ellipse even if Earth were a point
by SiVal 6y ago
(Ah, yes, pedantry. It has its own gravity. You can't tell me it's not a force. I can't resist its pull.)
It wouldn't be an ellipse even if Earth were a point mass. The gravity of the Moon and Sun, the gravitational lumpiness in the sky, has the same effect as the gravitational lumpiness underground. The combined result may be no closer to an ellipse than it is to a parabola.
- exDM69 6y agoBut on low earth orbit, the L2 term of earth's oblateness dominates by an order of magnitude compared to the moon and the sun, and the rest of the planets are negligible. Source is a table in the first chapters of Fundamentals of Astrodynamics.
- mcv 6y ago> "Ah, yes, pedantry. It has its own gravity. You can't tell me it's not a force. I can't resist its pull." It's not a force. From the right frame of mind[0], it's just a straight line. [0] Substituting for frame of reference.