Context:
Evidence suggesting that earth had a ring in the Ordovician
Earth may have had a ring during the middle Ordovician, from ca. 466 Ma.
Breakup of an asteroid passing within Earth's Roche limit likely formed the ring.
Among several features preserved is a near-equatorial band of impact craters.
Shading of Earth by the ring may have triggered a global icehouse period.
I remember learning about this fishie as a kid. I bought a book on the evolution of fishes as a kid cause I liked the pictures, but also learned quite a bit from it.