The Universe
Yours to Discover
Saturn was the most distant of the five planets known to the ancient skywatchers. In 1610, the Italian astronomer Galileo Galilei was the first to gaze at Saturn through a telescope. Much to his surprise, he saw a pair of objects on either side of the planet. He sketched them as separate spheres and wrote that Saturn appeared to be a triple-bodied planet. In 1659, the Dutch astronomer Christiaan Huygens, using a more powerful telescope than Galileo's, proposed that Saturn was surrounded by a thin, flat ring.
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Hubble Space Telescope images show that Saturn's polar regions have aurorae similar to Earth's. Aurorae occur when charged particles spiral into a planet's atmosphere along magnetic field lines.
Voyagers 1 and 2 flew by and photographed Saturn in 1981. The next chapter in our knowledge of Saturn is under way, as the Cassini- Huygens spacecraft continues its exploration of the Saturn system. The Huygens probe descended through Titan's atmosphere in January 2005, collecting data on the atmosphere and surface. Cassini will orbit Saturn more than 70 times during a four-year study of the planet and its moons, rings, and magnetosphere. Cassini-Huygens is sponsored by NASA, the European Space Agency, and the Italian Space Agency. Text courtesy NASA/JPL |
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◀ Saturn’s rings are wide, but thin. You can see the rings through a small telescope. When we look at the rings edge-on, they almost disappear because they’re so thin. In this photograph, the rings appear as a thin dark line. You can also see Tethys - one of Saturn's many moons - in the photograph. |
▲ Enceladus
Enceladus is the sixth-largest moon of Saturn. This icy moon has a global ocean hidden beneath its icy crust. Fountains of water vapour and ice particles burst through cracks in the ice, which then coat Enceladus with fresh layers of ice. This ice eventually buries some of the ancient impact craters.
▲ Mimas
The icy moon Mimas has a lot of craters, including one giant crater that was made by an object so big, it nearly shattered Mimas. This crater sort of makes Mimas look like the "Death Star" from Star Wars. Mimas is a small moon, with a diameter of just 396 kilometres, making it the smallest astronomical body known to be rounded into shape because of self-gravitation.
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▲ Titan
Titan is the largest moon of Saturn. It's also the only moon in the Solar System with a dense planet-like atmosphere and clouds. Its thick atmosphere is made mostly of nitrogen, along with some hydrocarbons, which makes it a smoggy atmosphere. Titan has rivers and lakes of liquid methane.
▲ Iapetus
Iapetus is the third-largest moon of Saturn, with a diameter of 1468 kilometres. It was discovered on October 25, 1671, by Giovanni Cassini. Iapetus is sometimes referred to as Saturn's two-face moon because one-half is as dark as charcoal, while the other half is as bright as snow.
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