Saturn

SATURN	· Your travel guide to the Solar System ·
	DEFINITION The second largest planet in the Solar System, sixth in line from the Sun. REASONS TO VISIT The most spectacular ring system of any planet in the Solar System This planet's density is so small that it would float on water - if there were an ocean large enough! NUMBER OF MOONS · 60		Solar System Jigsaw Can you build the Solar System?

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WHAT TO SEE Saturn is a 'gas giant' planet, like its larger neighbour Jupiter. Although it's not as brightly coloured as Jupiter, the planets have a very similar composition. The atmosphere, mostly hydrogen and helium, with traces of simple compounds, spins around the planet. Saturn's rings Saturn has the most spectacular ring system in the Solar System. These rings aren't solid, but made up of billions of separate chunks. They range from microscopic particles to rocks that are a few metres in diameter. When Galileo Galilei first spotted the rings, he was convinced that he was seeing three separate planets moving together. It's thought that the rings are made mainly of water ice, though some chunks may have rocky centres. No one is sure how they formed. But we do know that they change over time. Some particles are lost into space and these are replaced by debris released by Saturn's moons. The Cassini Gap On closer inspection, Saturn's rings are composed of many hundreds of smaller bands, with gaps in between. The largest break - the Cassini Gap - is visible from Earth. Saturn's moons may create some of these gaps as they sail through, clearing debris from their paths. SPOTTING SATURN FROM THE EARTH Saturn is the furthest planet that can be seen with the naked eye. But without the aid of a telescope, it can be tricky to spot against the background of stars. The give-away sign of any planet is that it doesn't 'twinkle' like stars do. If you catch the planet at the right time, you can see its rings. But every few years they seem to disappear. This is due to a change in the orientation of Saturn compared to Earth. When the rings are edge on, they are very hard to spot being only one kilometre thick.

TRAVEL INFORMATION Journey time · 29.4 Earth months 1 Saturnian year · 29.5 Earth years Contacting home · Time lag = 159.4 minutes Before you leave You'd be well advised to get hold of a satellite timetable before travelling. With many known moons and more still to be confirmed, Saturn's skies can be a nightmare to navigate. A pair of ultraviolet imaging goggles is also a must. Saturn has an impressive aurora display which changes hourly. It's formed when electrically charged particles from the solar wind hit Saturn's atmosphere. When you arrive As with all the gaseous planets, Saturn does not have a surface to land on. Watch out for the gale-force winds. At the equator, they can reach over 1500km per hour, and are mostly in the easterly direction. A trip to the poles is recommended, as here wind speeds decrease, as broad bands of gas travel in opposite directions. No probes have ever penetrated the planet's surface. The clouds are thought to hide a layer of metallic liquid hydrogen covering a rocky core. Even so, the planet has the smallest density of any in the Solar System. In fact, Saturn is so light that it'd float on water - if there were an ocean large enough! LOCAL HISTORY In Roman mythology, Saturn was the god of agriculture, and was the father of Jupiter. The Greeks referred to the planet as 'Cronus'. (www.bbc.co.uk)