Saturn

Saturn. . , Why does Saturn have "ears"? The 17th-century astronomer Christiaan Huygens was the first to suggest that the curious protrusions on both sides of Saturn were in fact a magnificent ring system. Scientists later discovered that the rings are made up of countless icy chunks of various sizes. Because Saturn's axis, like Earth's, is tilted, our view of the rings varies over a Saturnian year. , , Like Jupiter, Saturn is a gas giant made of hydrogen and helium. Because it rotates so fast, its atmosphere bulges outward at the equator. Saturn has at least 60 moons. The largest, Titan, is bigger than Mercury. , , Captions: , Inside the Observatory , You can sometimes view Saturn and its rings and moons during nighttime observing hours here at the Public Observatory. , , The image was taken through the Public Observatory-s 4-inch finderscope on June 1, 2013. The largest gap in Saturn's rings, the Cassini Division is visible. , , Viewing Our Solar System: , Cassini-Huygens , The first three spacecraft to visit Saturn, Pioneer 11 and Voyager 1 and 2, merely flew past it. The fourth, Cassini-Huygens, entered orbit around Saturn in 2004. Cassini released the Huygens probe to study Titan. Cassini itself focused on Saturn: its atmosphere, rings, magnetic field, and moons. It also captured images of Saturn's auroras. After completing its primary mission, Cassini went on to study seasonal changes on Saturn. Cassini is a joint mission of NASA and the European Space Agency. , , An artist's concept of Cassini orbiting Saturn. , NASA/JPL-Caltech , , As the Huygens probe descended toward the surface of Titan, it took these images of a river system on that large moon. With temperatures below 290°F (170°C), Titan's lakes and rivers contain liquid methane and ethane, not water. , ESA/NASA/JPL/University of Arizona , , ←In 2004 Cassini captured this mosaic of Saturn and its delicate rings. , NASA/JPL/Space Science Institute , , How to Learn More: , http://solarsystem.nasa.gov , http://saturn.jpl.nasa.gov