Facts About Saturn
Stellar Facts About Saturn
Basic Information about the Planet Saturn
Any list of the facts about Saturn would include reference to its size and its rings. Saturn is the sixth planet in distance from the Sun, and it is the second largest planet, behind Jupiter, in our solar system.
In the annals of Roman mythology, Saturn was known as the god of agriculture. The Greek god of agriculture, Cronus, was Uranus's son and he fathered Zeus, who is known in the planet Jupiter. Saturn is also the root of the English word “Saturday”.
Saturn was one of the earliest known of the planets, having been known since times prehistoric. Galileo observed it before anyone else recorded seeing it, with a telescope in the year 1610. Since then, facts about Saturn have been steadily expanded to include much information about what makes up the planet.
Galileo was confused when he was confronted with Saturn's odd appearance by telescope. The Earth passes through Saturn's rings' plane once every several years, as Saturn moves within its own orbit. So when viewed through a low resolution lens, Saturn's image changes quite drastically. Not until 1650 did Christiaan Huyguns infer correctly the geometry of the planet's rings. After that, astronomers were able to gather more pertinent information about the planet. The rings of Saturn were unique, as far as they knew back in those days, until 1977, when astronomers discovered faint rings around Uranus, and then around Neptune and Jupiter.
Saturn was paid a visit by the NASA probe Pioneer 11, in 1979. Later, it was also studied by Voyagers 1 and 2. A joint NASA/ESA project named Cassini also arrived at Saturn in 2004, and was scheduled to orbit the planet for four years or more. If the orbits of the studying ships do not decay, they are able to return images of the planet and send additional facts about Saturn for as long as they are able.
When you view Saturn through a smaller-sized telescope, it appears flattened. This view is caused by Saturn's rapid rotation, and its fluid state. Saturn is the least dense of all the planets. Its specific gravity of 0.7 is less than that of water. Saturn is composed of roughly 75% hydrogen and 25% helium. There are traces of ammonia, methane, water and “rock” in the planet's make-up as well.
The interior of Saturn is quite similar to that of Jupiter. It consists of a rocky core, a layer of liquid metallic hydrogen, and a molecular hydrogen layer. There are also traces present of various types of ices.
The interior of Saturn is very hot (12,000 degrees Kelvin at its core), and it radiates more energy out into space than the sun sends its way. This might not even be enough to explain the luminosity of Saturn – some other mechanism may cause this effect, maybe the “raining out” of helium, from deep in Saturn's interior.
Saturn's Moons
Saturn's 46+ moons are an interesting aspect of Saturn, for the observer. The large moon Titan has its own atmosphere, which can be seen as a faint outline when viewed through a powerful telescope. Titan is enclosed in several hazy layers. It possesses a surface pressure of 1.6 times that on Earth, and it is primarily made up of nitrogen. It also has about a 1% methane concentration. The surface temperature of Titan is bitterly cold, roughly -180 degrees Celsius. The atmosphere is very opaque, probably due to thick smog that seems to result from hydrocarbons interacting with sunlight. This is also the way smog forms on Earth.
The clouds around Titan are most likely composed of methane drops and liquid nitrogen, and astronomers speculate that Titan might have hydrocarbon oceans or lakes. One of the facts about Saturn that is disputed, is that some believe that life could have evolved on Titan, while some believe that it appears much too cold for life as we know it to have lived there.
Saturn has many other moons, mostly with surfaces so cold that the icy surface is as rigid as rock. The other moons also have many craters displayed, from meteor impacts. Most of Saturn's moons are locked tidally, and as they orbit, they have the same face turned towards their mother planet.
The satellite Rhea seems to have many craters, based on viewing the moon via telescope. Iapetus, another moon, has one side that is ten times darker than the other. Some of Saturn's other moons include Mimas, which displays an impact crater that is ¼ the diameter of the moon. Enceladus may be active geographically because of the tidal heating by Saturn. Tethys has one large flat crater that is half the diameter of the moon, and also has a large canyon visible by powerful telescopes. The moon Dione is cratered heavily.
Astronomers have found two smaller moons that share Tethys' orbit, and one small moon that shares the orbit of Dione. This “orbit-sharing” had previously not been seen before a detailed investigation of Saturn's own system was undertaken. Hyperion has a chaotic rotation caused by Titan's gravity. And the outermost of all Saturn's moons, named Phoebe, may actually be a captured asteroid.
Due to a variety of instances in study, we now know that one of the facts about Saturn states that her rings may in fact be stabilized by her moons. Their gravitational forces may be one of the things that keep the rings where they are. Two small “shepherd moons” named Pandora and Prometheus, keep one of Saturn's rings narrow. Scientists have found that shepherd satellites play a role in the shapes of rings, but they still don't fully understand the details about the roles these shepherd satellites play. (continued...)