ABOUT SATURN: Saturn has been known since prehistoric times. It is the sixth planet from the sun, and the second largest in the solar system, a gas giant ranked behind only Jupiter. Saturn is composed primarily of hydrogen, with smaller amounts of helium and other trace elements. Its interior is made of a small core of rock and ice, surrounded by a thick layer of metallic hydrogen and a gaseous outer later. Saturn is best known for its prominent system of rings, which are mostly comprised of ice particles, rocky debris, and dust. Astronomers believe the rings may have been formed from larger moons that were shattered by impacts from comets and meteoroids. The planet also has at least 62 moons; most of them are quite small, but the largest is Titan, which is bigger than the planet mercury and is the only moon in the entire solar system to have a significant atmosphere.
A DIFFERENT TYPE OF RING: "Einstein rings" are an optical illusion created when the fabric of spacetime is warped by the presence of massive objects, like stars or entire galaxies. The effect is known as gravitational lensing, and it acts like a giant magnifying glass in space, bending and amplifying the light of more distant objects. Light from a distant galaxy can be deflected by an intervening galaxy to create an arc or multiple separate images. When both galaxies are exactly lined up, the light forms a bulls-eye pattern -- the Einstein ring -- around the foreground galaxy.