"

 Orbit of the Moon 

So apparently there are some sources that describe the Moon's orbit as convex, and some that describe it as concave.  People have a tendency to mix up the terms convex and concave.  Damn whatever idiot decided to use such similar words for such an obscure concept.  Rather than attempt to determine which sources have more authority, I suggest we look at the actual definitions of the words.  All the sources agree that the Moon's orbit has no loops.  And the Wikipedia article Convex and concave polygons seems to imply that a circle without loops would be convex, rather than concave.

Some of the sources describe it as convex/concave inwards vs. convex/concave outwards.  I think that distinction is nonsense.  Something is either convex or concave.  Convexity and concavity have no distinction with respect to inwards or outwards.  When they say that the Moon's orbit is convex ""with respect to the Sun"" I think they just mean that as opposed to convex with respect to the Earth.

So I still think I'm right on this, and I'm not inclined to change my edit.  Except maybe to link to the article on the definition of convex, to avoid this misunderstanding in the future.  But now that I've expanded on my reasoning, if you still think it contains a mistake, feel free to let me know why. -   "