Planet Saturn

Planet Saturn is the second largest planet in our solar system however is the only planet that has a density less than water and would therefore float in a large enough body of water.


Saturn Overview

Rings of Saturn

Saturn’s Weather

Structure of Planet Saturn

Saturn’s Sky

Missions to Saturn

Where in the Solar System?

Quick Stats




Saturn Overview

Planet Saturn
This image was taken by NASA’s Cassini spacecraft on the 19th of July 2013. Sat in Saturn’s shadow Cassini managed to take this amazing image showing many moons and even earth in the distance.


The Greeks called the planet Kronos or Cronus after the father of Zeus (Jupiter’s counterpart). Kronos was also the god of agriculture and fertility which led the roman’s to call the planet Saturn after their god of agriculture.


Saturn is the second largest planet in our solar system and has a similar atmosphere to Jupiter with 97% hydrogen, 2.5% helium, and 0.5% methane. Saturn however is the only planet that has a density less than water and would therefore float in a large enough body of water. Saturn was the most distant planet that ancient civilisations knew of as it is the furthest planet, visible by the naked eye.



Rings of Saturn


In 1610 Galileo looked at the planet with his telescope and was the first person to see Saturn’s rings. His telescope wasn’t powerful enough to make them out clearly and so initially he thought it was three bodies very close together. After further observations Galileo started to sketch Saturn with two arms either side of the planet but it wasn’t until 1659 when Dutch astronomer Christian Huygens observed Planet Saturn with a more powerful telescope and suggested that Saturn had a very large thin ring around it. Then in 1675 an astronomer called Jean-Dominique Cassini discovered a gap in the ring which we know call the Cassini Division.

Saturn has 7 main rings in total each designated a letter from A-G in order of their discovery. The Cassini division is the gap between rings ‘A’ and ‘B’ which is 4,800km (3,000mi) across and caused by the gravitational forces from one of Saturn’s moons called Mimas.


Rings of Saturn


Ring A is 14,600 km (9,072 mi) across

Ring B is 25,500 km (15,845 mi) across

Ring C is 17,500 km (10,874 mi) across

Ring D is 7,500 km (4,660 mi) across

Ring E is 300,000km (186,411mi) across

Ring F is 30-500 km (19- 311 mi) across

Ring G is 8,000 km (4,971 mi) across


The rings of Saturn are made of mainly of frozen water and their age is at yet not known. They stretch from 66,970km (41,632mi) to 480,000km (298,258mi) from Saturn’s surface covering a distance of 413,030km (256,626mi) yet they’re only an average of 10m (30ft) high.



Saturn’s Weather


Planet Saturn has a myriad of weather including rain, snow, strong winds and lightning storms. At each of Saturn’s poles a Massive vortex has been observed by NASA’s Cassini spacecraft, from which hot gases, which have been heated from the planets interior, spew out creating vast thunderstorms. The winds in Saturn’s upper atmosphere reach speeds of 1,800,00km/h (1,118,468mi/h) which is almost five times stronger than the most powerful hurricane force winds on Earth.


Weather in Saturn


The above animation shows a huge anti-cyclone in Saturn’s stratosphere which was visible for several months. At its largest point it covered almost a quarter of Saturn’s circumference (about 62,000km). A storm lasting some six months seems immense compared to our weather but this was just the visible sign of a super-hot vortex. The event started as a storm in Saturn’s troposphere which continued a few years after the visible signs ended.   



Structure of Planet Saturn


Layers of Saturn


The outer atmosphere of planet Saturn comprises mainly of hydrogen and helium gas, but further in the hydrogen become denser forming a layer of liquid hydrogen. Deeper still and the hydrogen has become so dense that it formed a shell of metallic hydrogen which engulfs the planets centre. Saturn’s core, which has a radius of 6,000km (3,700mi), is a solid mass made from rock and frozen material such as water and other compounds.



Saturn’s Sky

Saturn's Sky


This image was taken by NASA’s Cassini spacecraft in January 2005 and is a true colour image of Saturn’s skies in the northern hemisphere. The lines are shadows formed by Saturn’s rings and the moon Mimas can be seen on the bottom left.


Planet Saturn normally looks a golden brown colour from Earth but when viewed from up close, so that just the hydrogen rich atmosphere is in view you can see the true colour of its skies. The hydrogen molecules scatter light in the same way that the particles in our atmosphere do and although many colours are scattered, blue is most visible as it is at the short end of the light spectrum. This process is known as Rayleigh scattering.



Missions to Saturn


On the 15th of October 1997 Cassini was launched into space along with the European Space Agency’s Huygens probe in a joint mission called the Cassini-Huygens mission which is to study Saturn’s System.


The probe was equipped with six instruments designed to study Saturn’s largest moon ‘Titan’. On the 14th of January 2005 it landed on Titan’s surface after parachuting through its atmosphere. Even during its descent and upon its landing the probe sent back important data which has helped build a more detailed picture of this icy moon.


Cassini’s mission was initially a four year exploration of the Saturn System which it completed in June 2008 but due to the success of its mission and health of the spacecraft NASA extended the mission calling it the ‘Cassini Equinox Mission’. Cassini completed this mission in September 2010 and now has been given another extended mission called the ‘Cassini Solstice Mission’ which is due to end in September 2017 although this may be extended further. On the 23rd of May 2013 Cassini will make a fly-by of Titan gathering more information before continuing around the system.



Where in the Solar System?


Where in the Solar System


Quick Stats





7 Main Rings

Orbit Period

10,738.35 Earth Days (29.4 Earth Years)

Rotation Period

10.656 Hours

Equatorial Radius

60,268km (37,449mi)

Overall Density

0.70 g/cm3

Mass (Earth = 1)


Gravity (Earth = 1)


Average Temperature

-178°C (-228°F or 95.15 °K) (Coldest Planet)

Maximum Temperature



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