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’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 |
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Notes on the above figures:
- Orbits are invariably elliptical in nature. The average distance from the sun that appears above is also known as a 'semi-major axis', which is the mean (average) radius of the elliptical orbit.
- Axial tilt is also known as 'obliquity to orbit' and is the angle of rotation of the body itself with an imaginary line drawn through both poles, relative to its plane of orbit.
- Radius figures quoted are equatorial measurements. As most bodies exhibit 'oblateness' - that is to say that they appear slightly squashed - the radius from the centre to the poles would invariably be shorter.
- The Kelvin temperature scale is used for all temperature measurements above. 0K is equivalent to -273.15°C (degrees Celsius). To convert from K to C, simply subtract this figure from the Kelvin temperature given.
- Use of 'Index Notation' for very large numbers as above can be explained as follows; 106 = 10 x 10 x 10 x 10 x 10 x 10, or 1,000,000. For example, if you see a number that appears as 6x1011 then that number written in full would be 6 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 - or 600,000,000,000. Index notation allows us to write very big (or very small) numbers down far more concisely.