Saturn is the sixth planet from the Sun and second largest planet of the Solar System in terms of diameter and mass. If compared, it is easy to see why Saturn and Jupiter have been designated as relatives. From atmospheric composition to rotation, these two planets are extremely similar. Because of these factors, Saturn was named after the father of the god Jupiter in Roman mythology.
Size of Saturn compared to the Earth
Facts about Saturn
- Saturn is the sixth planet from the Sun, and last of the planets known to ancient civilizations. It was known to the Babylonians and Far Eastern observer.
- Saturn is one of five planets able to be seen with the naked eye. It is also the fifth brightest object in the solar system.
- In Roman mythology Saturn was the father of Jupiter, king of the gods. This relationship makes sense given that the planets Saturn and Jupiter are similar in so many respects, including size and composition. The Greek counterpart is known as Cronus.
- The most common nickname for Saturn is “The Ringed Planet”, a nickname arising from the large, beautiful and extensive ring system that encircles the planet. These rings are mostly made from chunks of ice and carbonaceous dust. They stretch out more than 12,700 km from the planet but are only a mere 20 meters thick.
- Saturn gives off more energy than it receives from the Sun. This unusual quality is believed to be generated from the gravitational compression of the planet combined with the friction from large amount of helium found within its atmosphere.
- It takes Saturn 29.4 Earth years to orbit the Sun. This slow movement against a backdrop of stars led to the planet being nicknamed “Lubadsagush” – or “oldest of the old” – by the ancient Assyrians.
- Saturn has the fastest winds of any other planet in our solar system. These winds have been measured at approximately 1,800 km per hour (1,100 miles per hour).
- Saturn is the least dense planet in the solar system. It is made mostly of hydrogen and has a density which is less than water – which technically means that Saturn would float. The layers of hydrogen get denser further into the planet, eventually becoming metallic and leading to a hot interior core.
- Saturn has 150 moons and smaller moonlets. All of these moons are frozen – the largest of which are Titan and Rhea. The moon Enceladus also appears to have an ocean hidden below its frozen surface.
- Saturn’s moon Titan is the second largest moon in the Solar System, behind Jupiter’s moon Ganymede. It has a complex and dense atmosphere made mostly of nitrogen and is composed from water ice and rock. The frozen surface of Titan has liquid methane lakes and a landscape which is covered with frozen nitrogen. It is possible that Titan may be a harbour for life – but that life would not be similar to life on Earth.
- Saturn is the flattest of the eight planets. With a polar diameter that is 90% of its equatorial diameter, Saturn is the flattest of all the planets. This is because of the planet’s low density and fast rotation speed – it takes Saturn 10 hours and 34 minutes to turn on its axis.
- Saturn has oval shaped storms which are similar to those of Jupiter. Scientists believe that the hexadiagonal-shaped pattern of clouds around Saturn’s north pole may be a wave pattern in the upper clouds. There is also a vortex over the south pole which resembles hurricane storms on Earth.
- Saturn appears a pale yellow color because its upper atmosphere contains ammonia crystals. Below this top layer of ammonia ice are clouds that are largely water ice. Even further below that are layers of sulfur ice and cold hydrogen mixtures.
- Saturn has been visited by four spacecraft. These are Pioneer 11, Voyager 1 and 2 and the Cassini-Huygen mission. Cassini entered into orbit around Saturn on July 1, 2004 and continues to send back information about the planet, its ring and many moons.
- The magnetic field on Saturn is slighter weaker than Earth’s magnetic field. Saturn’s magnetic field strength is around one-twentieth the strength of Jupiter’s
- Saturn is known as a gas giant, but scientists believe it has a solid rocky core surrounded by hydrogen and helium
- Saturn and Jupiter combined account for 92% of the entire planetary mass in the solar system.
- The interior of Saturn is very hot, reaching temperatures of up to 11,700°C (21,000 °F).
- Saturn is 1,424,600,000 km from the Sun. This is around 0.9 billion miles.
More information and facts about Saturn
Other than Earth, Saturn is easily the most recognizable planet in the Solar System. The reason for this is obvious. Although the other gas giants possess a planetary ring system, none can match the size or beauty of the one found encircling Saturn.
Saturn is the last of the planets known to ancient civilizations. It is also one of the least understood in modern times. With the Cassini-Huygens planetary mission that is currently underway, scientists hope to not only learn more about Saturn, but also Saturn’s moons and its planetary ring system.
Saturn’s atmosphere is composed of roughly 96% hydrogen and 4% helium, with trace amounts of ammonia, acetylene, ethane, phosphine and methane. It has a thickness of approximately 60 km. In the highest layer of the atmosphere, wind speeds reach 1,800 km/h, easily some of the fastest in the entire Solar System.
Although not as visible as those seen on Jupiter, Saturn does possess a horizontally banded cloud pattern. Furthermore, these bands are considerably wider near Saturn’s equator than those found at Jupiter’s equator. These cloud patterns were unknown until the Voyager missions beginning in the 1970s. Since that time, technology has increased to the point that Earth-based telescopes can now view them.
Another fascinating phenomenon that can be found in Saturn’s atmosphere is the appearance of great white spots. These are storms on Saturn, which are analogous to the Great Red Spot found on Jupiter, though they are much shorter lived. The Hubble Space Telescope observed such a storm in 1990, though it was not present when the Voyager spacecraft had flown by in 1981. Based on historical observations, it appears that these storms are periodic in nature, occurring approximately once per Saturnian orbit.
The interior of Saturn is believed to be extremely similar to Jupiter’s in the composition of its three layers. The innermost layer is a rocky core between 10-20 times as massive as the Earth. The core is encased in a layer of liquid metallic hydrogen. The outermost layer is composed of molecular hydrogen (H2). The only significant difference between the interiors of Saturn and Jupiter is thought to be the thickness of the two outer layers. Whereas Jupiter has a metallic hydrogen layer of 46,000 km and molecular hydrogen layer of is 12,200 km, those same layers on Saturn have a thickness of 14,500 km and 18,500 km, respectively.
Saturn, like Jupiter, emits approximately 2.5 times more radiation than it receives from the Sun. This is due to the Kelvin-Helmholtz mechanism, which essentially creates energy through gravitational compression of the planet due to its enormous mass. However, unlike Jupiter, the total amount of energy emitted cannot be accounted for through this process alone. Instead, scientists have suggested that the planet generates additional heat through the friction of helium rain.
A unique feature of Saturn is that it is the least dense planet in the Solar System. Although Saturn may have a dense, solid core, the large gaseous outer layer of the planet makes its average density a mere 687 kg/m3. As result, Saturn is lighter than water.
Orbit & Rotation
The average orbital distance of Saturn is 1.43 x 109 km. This means that Saturn is, on average, about 9.5 times the distance from the Earth to the Sun. The result of such a long distance is that it takes sunlight about an hour and twenty minutes to reach Saturn. Moreover, given Saturn’s distance from the Sun, it has a year lasting 10,756 Earth days; that is, about 29.5 Earth years.
At .0560, Saturn’s orbital eccentricity is the third greatest behind Mercury’s and Mars’. The effect of this large eccentricity is a substantial distance between the planet’s perihelion (1.35 x 109 km) aphelion (1.50 x 109 km) of about 1.54 X 108 km.
Saturn’s axial tilt of 26.73 is very similar to the Earth’s. Thus Saturn also experiences seasons like the Earth. However, due to Saturn’s distance from the Sun, it receives significantly less solar radiation year-round, and so Saturn’s season are much more subtle than those on Earth.
Much like Jupiter, Saturn is very interesting when it comes to its rotation. Having a rotational speed of roughly 10 hours 45 minutes, Saturn is second only to Jupiter for the fastest rotation in the Solar System. This extreme rotation causes the planet’s shape to take on the shape of an oblate spheroid; i.e. a sphere that bulges near its equator.
A second feature of Saturn’s rotation is the different rotational speeds found between the different visible latitudes. This phenomenon is due to Saturn being primarily gaseous rather than solid.
The ring system of Saturn is the most prominent found in the Solar System. They are composed primarily of billions of tiny ice particles, with traces of dust and other debris. This composition explains why the rings are visible to Earth-based telescopes—ice is very reflective of sunlight.
There are seven broad classifications among the rings: A, B, C, D, E, F, G, each receiving its name in the order it was discovered. The main rings most visible from Earth are A, B and C. Each ring is really just a collection of thousands of smaller rings packed very closely together. Furthermore, between each ring there are gaps. At 4,700 km and occurring between rings A and B, Cassani is the largest of these gaps.
The main rings begin roughly 7,000 km above Saturn’s equator and extend out another 73,000 km. Interestingly, though this radius is substantial, the actual thickness of the rings is no more than about one kilometer.
The most common theory used to explain the formation of the rings is that a medium-sized moon orbiting Saturn broke apart due to tidal forces when its orbit became too close to Saturn.