Galileo did not discover any planet rings. While he did make groundbreaking observations of the planets with his telescope, he observed Saturn's rings as two "ears" or "handles" on either side of the planet. He was unable to resolve the rings into their true form due to the limitations of his telescope.

It wasn't until 1655 that Christiaan Huygens observed Saturn's rings with a more powerful telescope and correctly described them as a flat, thin ring surrounding the planet.