What observational facts lead to the conclusion that the small outer satellites of Jupiter were captured by its gravitational field rather than being formed at the same time as the planet?

Question

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The fact that the small outer satellites of Jupiter move in orbits that are steeply inclined to Jupiter's equator, many of them in a retrograde direction, opposite to Jupiter's rotation, suggests that they were not formed at the same time as the planet. This is because it is unlikely that they would have formed in such highly inclined and retrograde orbits. It is more probable that they were captured by Jupiter's gravitational field from elsewhere in the solar system.

What Observational Facts Lead to the Conclusion That the Small