Saturn

Saturn is the sixth planet from our Sun and the second largest planet in our solar system. Accompanied by a large ring, Saturn is unique amongst the other planets. It's not the only planet to have rings, but no other planets are as spectacular or complex. Like the fellow gas giant Jupiter, Saturn is a massive ball composed of mostly hydrogen and helium.

Surrounded by more than 60 moons, Saturn is home to one of the most fascinating landscapes in our solar system. From the jets of water that spray from Enceladus to the methane lakes on Titan. The Saturn system is place for decades of discovery and still holds many mysteries.

Saturn has been known since Ancient times, and is the farthest planet discovered from Earth with the human eye. The planet is named after the Roman god of agriculture and wealth, he is also the father of Jupiter.

## Size and Distance

Saturn is nine times wider than Earth, with a radius of 36,183.7 miles (58,232 kilometres).

Saturn is 9.5 astronomical units away from the Sun. One astronomical unit (abbreviated as 'AU') is the equal distance from the Sun to Earth.

Sunlight takes 80 minutes to travel to Saturn.

## Orbit and Rotation

Saturn has the second shortest day in our solar system. One day on Saturn lasts 10.7 hours (the time it takes for Saturn to complete on rotation). For Saturn to complete one rotation around the Sun (a year in Saturnian time), it would take 29.4 Earth years (10,756 Earth days).

Saturn is tilted at a 26.73 degree angle, with respect to its orbit around the Sun. This means that Saturn experiences season, like Earth.

## Structure

Like Jupiter and other gas giants, Saturn is made of hydrogen and helium. At Saturn's centre is a dense core made of metals like nickel and iron which are surrounded by rocky material and other compounds solidified by the extreme pressure and heat. It is enveloped by liquid metallic hydrogen inside a layer of liquid hydrogen - similar to Jupiter's core but much smaller.

It's hard to believe that Saturn is the only planet in our solar system whose density is less than water. If such a colossal thing existed, the gas giant would be able to float in water.

## Formation

When the solar system settled into its current state, 4.5 billion years ago, gravity pulled swirling gas and dust to form the massive gas giant. About 4 billion years ago, Saturn settled into its current position where it is the sixth planet from the Sun. Like Jupiter, Saturn is made of hydrogen and helium, the same components the Sun is made of.

## Surface

Saturn doesn't have a true surface, since it is a gas giant, and is mainly swirling gases and liquids deeper down the planet. Whilst a spacecraft would have nowhere to land on Saturn, it wouldn't go unscathed either. The extreme pressure and temperature deep inside the planet would, crush, vaporise and melt anything that entered the gas giant.

## Atmosphere

Saturn is covered with clouds that appear as faint stripes, jet streams and storms. The planet is mainly differentiated shades of yellow, brown and grey.

Winds in the upper atmosphere reach 1,600 feet per second (500 metres per second) in the equatorial region. In comparison, the strongest hurricane-force winds recorded on Earth reached up to 360 feet per second (110 metres per second). The pressure - the same when you dive deep underwater - is so powerful that it squeezes gas into liquid.

Saturn's north pole has a very interesting atmosphere - a six-sided jet. This hexagon-shaped pattern has a been a long focus of study which was first noticed by images from the Voyager 1 spacecraft and has been closely observed by the Cassini spacecraft ever since. Spanning a width of 20,000 miles (30,000 kilometres), the hexagon-shaped pattern produces powerful wavy jet streams that can reach up to 200 miles per hour (322 kilometres per hour) with a massive, rotating storm at the centre. Nowhere else in the solar system has weather like this.

## Magnetosphere

Saturn's magnetic field is 578 times greater than Earth's but smaller than Jupiter. Saturn, the rings and many satellites are within the enormous magnetosphere, the region of space of which the electrically charged particles are influenced bny Saturn's magnetic field than by solar wind.

Aurorae occur when charged particles spiral into a planet's atmosphere along its magnetic field lines. On Earth, these charged particles come from solar wind. Cassini showed that some of Saturn's aurorae are like Jupiter's and are largely unaffected by solar wind. Instead, these aurorae are caused by Saturn's moons and magnetic field's rapid rotation rate. These "non-solar-originating" aurorae are not completely understood yet.

## Rings

Saturn's rings are believed to be pieces of comets, asteroids or shattered moons that broke up before they reached the planet, torn apart by Saturn's powerful gravity. They're made up of billions of small chunks of ice and rock coated with another material such as dust. The ring particles are mostly range from tiny, dust-sized icy grains which measure in as big as a house. A few particles are as large as mountains. If you were to look from the cloud tops of Saturn, the rings would appear white and interestingly, each ring orbits around a different speed around the planet.

Saturn's ring system extends to a width of 175,000 miles (282,000 kilometres) from the planet, yet the vertical height typically measures in at 30 feet (10 metres) in the main rings. Named alphabetically the date they were discovered, the rings are relatively close to each other, with an exception for the Cassini division which has a gap that measures 2,920 miles (4,700 kilometres) wide. The main rings are A, B and C. Rings D, E, F and G are fainter and are more recently discovered.

Starting at Saturn, the rings are named D, C, B, Cassini Division, A, F, G and finally E. Farther out from Saturn, there is a very faint Phoebe ring in the orbit of Phoebe, Saturn's moon.

## Moons

Saturn is home to a vast array of moons (up to 83). From the haze-shrouded Titan to the crater-filled Phoebe, each of which has a very interesting story of how it ended up in Saturn's orbit. Currently, 53 moons have been confirmed and 29 moons are awaiting confirmation.

> More on Saturn's Moons

## Human Life

Saturn's extreme temperatures and pressure make human life very unlikely to colonise on this planet.