Saturn

The planet Saturn is known for its thousands of beautiful rings and is the sixth furthest away planet from the Sun. It is also the furthest away planet in our solar system that you are able to see with the naked eye in the night sky.

Saturn is another of the “gas giant” planets along with Jupiter, Uranus and Neptune.

All of the gas giant planets have rings around them but Saturn’s rings are by far the most spectacular when viewed through a telescope.

Saturn is the Roman name for Cronus which was the lord of the titans in Greek mythology. Saturn is the second largest planet in our solar system after Jupiter and it has a radius that is roughly nine times that of the Earth.

Saturn and its 3 moons Tethys, Dion and Rhea taken by Voyager 2 Close-up of Saturn's rings by Voyager 2 Saturn's largest moon, Titan. Taken by the Cassini spacecraft
Click an image above to view full size image. Hover over for description.

Saturn’s Rings

Saturn is most famous for the extraordinary series of rings that extend from 6,630 km to 120,700 km above the equator of the planet. Each of the thousands of individual rings are around 20 metres thick and they are largely comprised of ice water (97%) with the remaining 7% made up of carbon. The individual particles that the rings comprise of can be as small as specks of dust up to objects as large as 10 meters across.

Scientists are unsure as to why the rings around Saturn are so pronounced, but there are two main theories. The first is that the rings are as a result of a previous moon of Saturn that was destroyed during a particular event and the material has made the rings.

The other theory is that the rings were formed from the original nebular material that went towards the original creation of the planet.

Saturn’s moons

Saturn is known to have a large number of moons and so-called moonlets. Recent figures suggest that there are in excess of 150, with this figure begin regularly revised – many of these moons are yet to have formal names. Around 50 of the moons of Saturn are 50 km or less in diameter.

The second largest of Saturn’s moons is called Rhea. Observations have shown that Rhea may have a ring system and an atmosphere of its own.

The largest of Saturn’s moons is called Titan. This is the second largest moon in the solar system (second only to Jupiter’s Ganymede) which is slightly larger than the planet Mercury. Titan is a fascinating moon in the sense that it has a think nitrogen based atmosphere that was likely similar to the atmosphere of a very young planet Earth.

In 2013 scientists at the IAA-CSIC detected polycyclic aromatic hydrocarbons in the upper atmosphere of Titan. This type of material can be potential precursors to life!

Facts about Saturn

Saturn completes a full rotation on its axis every 10.7 hours which means this constitutes a day on Saturn. For Saturn to make a full orbit around the Sun it takes 29 Earth years.

Saturn is similar to Jupiter in that they are both gas giant planets that do not have a solid surface.
Saturn is on average 1.4 billion kilometres away from the Sun.

The pale yellow colour of Saturn is thought to come about because of the presence of ammonia crystals in the upper atmosphere.

The speed with which Saturn rotates contributes to a flattening effect – its polar diameter is 90% of the equatorial diameter.

Saturn is the fifth brightest object in the night sky. It can be seen with the naked eye if you know where to look, but with good binoculars or a telescope if it possible to view Saturn with relative ease.

The planet has a mass which is 95 times that of the Earth and it is 142,750 kilometres in diameter.

The speed with which Saturn rotates causes extreme weather systems. It is believed that wind speeds are able to reach a peak of 1,800 km/h and that there is a constant whirlwind type storm at the Saturn’s south pole that can be viewed with a powerful telescope.

Due to the fact that Saturn’s axis is titled it means that depending on what stage the planet is in during orbit we will get to see a different view of the rings when observed from Earth.

The major rings of Saturn have been named by the alphabet. For example, Ring A, Ring B, etc. through to Ring G.

Some of the outer rings are actually held in place by nearby moons.

Figures and Statistics

  Saturn Earth Ratio (Planet to Earth)
Rotation period - (hours) 10.656 23.9345 0.445
Length of day - (hours) 10.656 24.00 0.444
Length of year (earth days) 10840.5 365 29.7
One complete orbit takes (earth days) 10759.22 365.256 29.457
Radius (km) 60268 6378.1 9.449
Mass (1024 kg) 568.36 5.9726 95.203
Volume (1010 km3) 82713 108.321 763.592
Density (kg/m3) 687 5514 0.125
Distance from Earth - Min (106km) 1195.5 - -
Distance from Earth - Max - (106km) 1658.5 - -
Average distance from Sun (106km) 1433.53 149.6 9.582
Orbital radius (106km) 1353 - 1515 147 - 152 9.2 - 9.97
Orbital velocity (average - km/s) 9.68 29.78 0.325
Rotational velocity (km/h) 35500 1674.4 21.202
Surface gravity (m/s2) 10.44 9.81 1.064
Surface temp - Average (K) 137 184 0.745
Axial tilt (degrees) 26.73 23.44 1.140
Number of natural satellites (moons) 62 1 62