An ancient Mars might have had rings, and the planet may someday boast them again, according to a model published today in Nature Geoscience. Scientists think a prominent basin on Mars may have been formed by large object colliding with the planet some 4.3 billion years ago, Astronomy magazine writes. That collision should have formed rings of debris, which overtime consolidated into moons, according to the new model. But now, the model says, Mars’s moon Phobos is on a gravity-driven, 70-million-year course back towards the planet, a path that will cause it to be ripped apart by tidal forces and spun out into a new set of rings. The researchers suggest that, over several billion years, Mars might have completed this alternating cycle between rings and moons as many as seven times.