[VadeRetro]

That would surprise me. As massive bodies are "wells" in spacetime, the LaGrange points would be mountain peaks - an unstable location for masses to be.

The point is that they are indeed "wells." If they drift in slowly and aren't too massive, they'll stay. It takes energy to move them out.

(I'll admit to being unfamiliar with exactly what Lagrange calculated. But if he were wrong, we'd have noticed by now. I believe the opposite has happened.)

[VadeRetro]

The point is that they are indeed "wells." If they drift in slowly and aren't too massive, they'll stay. It takes energy to move them out.

"If things drift in . . ." May the Pronoun Police question me all night!

[GregoryFul]

You are right that the L4 and L5 points are "wells", the L1 through L3 points are "peaks".