Saturn, Lord of the Rings!
In addition to Jupiter being in the evening sky, to the east of Jupiter this time of year is the 6th planet out from the Sun. This is the planet Saturn, named after the Roman god of Agriculture and father of Jupiter in Roman mythology. It is the 9th brightest object in the sky and the most distant planet one can see with the naked eye.
Saturn has been known since prehistoric times. It is almost 10 times further from the Sun than Earth is. It only has one-eighth the average density of Earth; however, with its larger volume, Saturn is over 95 times more massive. The density of Saturn is so low that if we had an ocean big enough to put Saturn in, it would float!
Saturn’s diameter is 9 times bigger than Earth, about 72,367 miles. About 764 Earths can fit inside its volume. The planet, like Jupiter, has no solid surface. Its atmosphere contains hydrogen, helium, methane and ammonia. The yellowish color of Saturn is due to high concentrations of helium in its atmosphere.
The most prominent feature one can see on Saturn is the planet’s Hexagon feature around its North Pole. This is a cyclonic storm that can fit more than one quarter of the Earth inside. This storm has been roaming in the same far northern latitudes since the Voyager 2 flyby of 1981.
Saturn orbits the Sun in 29 ½ years. Its rotation is the 2nd fastest of all the planets: only 10 hours and 33 minutes for Saturn to make one single day! Its cloud tops are very cold being so far from the Sun. At the temperature of -265°F, should one travel among the planet’s cloud tops, it would be raining liquid helium!
Saturn is known for its beautiful set of rings. Galileo was the first to observe Saturn in 1610. He called it a “planet with ears.” The ears Galileo mentioned are actually its rings. His telescope's resolution was too poor for him to see what they really were. It is believed that the rings formed when a planet or large moon smashed into Saturn long ago. Its debris resulted in the ring system we see today. It has been determined that the rings are made of ice, dust and rocks. The 7 rings are named after the first 7 letters of the English alphabet, in order of their discovery.
Saturn has a family of 82 moons. All are named after mythological figures associated with the Roman Titan of time, Saturn (equated to the Greek Cronus). In particular, the very first discovered satellites were named after Titans, Titanesses and Giants—brothers and sisters of Cronus. When in the 20th century the names of Titans were exhausted, the remaining discovered moons were named after different characters of the Greco-Roman mythology or giants from other mythologies.
The first ten moons in order from Saturn are Janus, Mimas, Enceladus, Dione, Tethys, Rhea, Titan, Hyperion, Iapetus and Phoebe.
Saturn’s largest moon is Titan. It was discovered in 1655 by Christiaan Huygens. Its diameter is 3,199.7 miles. Titan is the second biggest moon in the Solar System after Jupiter’s Moon Ganymede. It was the first moon in the Solar System discovered to have an atmosphere, a thick mixture of 95% nitrogen and 5% methane. Titan is so cold that methane acts like water does on the Earth - it can exist as a gas, a liquid, or a solid ice!
A spacecraft called Cassini arrived at Saturn in 2005 and launched a probe called Huygens to land on Titan. The probe lasted for nearly a half hour after landing. It discovered liquid methane lakes and took this picture of the surface through the methane haze.
Titan is not the only moon with an atmosphere. The 7th largest moon of Saturn Enceladus is only 310 miles in diameter. The Cassini spacecraft found nitrogen geysers reaching all the way out into space. In fact, it replenishes Saturn's "F - Ring" with more ices.
Another interesting moon is Mimas. The large crater pictured here looks very much like the Death Star from Star Wars. Named "Herschel" after the astronomer who discovered Uranus, the crater is believed to have been created by a large impact that almost destroyed the moon!
Saturn can be found in the Southeast in the direction of the constellation Sagittarius. Look for the teapot and find the two stars in the handle of the teapot. There in the upper northeast you will find Jupiter. To the east of it you will see a bright orange yellow object, that is Saturn. With binoculars or a telescope, you should be able to see its rings and at least one of its moons.