SaturnRings.jpg

A new theory proposed by a planetary scientist at the Southwest Research Institute in Boulder, Colorado, suggests that Saturn's many rings were formed when a dying moon smashed into the planet. Robin Canup's theory, published in the new issue of Nature, suggests that the rings were once the icy outer layer of that long-gone moon. "Not only do you end up with the current ring, but you can also explain the inner ice-rich moons that haven't been explained before," Canup said, according to a story published this morning by ScienceNews. "Once you hear it, it's a pretty simple idea," Canup said. "But no one was thinking of ... losing a satellite like Titan. That was the conceptual break."

Images: NASA/CXC/M.Weiss; Via Wired Science/ScienceNews.

View more Pictures of the Day.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.