Saturn was the most distant planet known to the ancients, and is second in size only to Jupiter as it has an equatorial diameter of 75,000 miles. The first recorded observations of Saturn seem to have taken place in mid-seventh century BC Mesopotamia, and in 650 BC there is a record that Saturn "entered the Moon" (presumably an occultation). Its mass is 95.184 times greater than that of Earth, in fact 750 Earths could fit inside its globe. It orbits the Sun every 29.458 years at a mean distance of 886 million miles (9.529 AU), travelling 12° per annum, with an orbital eccentricity of 0.0556.
Like Jupiter, it also has a rapid rotation, once every 10 hours 14-38 minutes, and so is considerably flattened at its poles. It is brighter than all stars apart from Sirius and Canopus, but less bright than Venus, Jupiter or Mars at its brightest.
Saturn appears as a pale yellow disk crossed by darker bands, which are the upper parts of frozen ammonia crystal clouds, floating in hydrogen and helium which become metallic lower down. The cloud tops extend 600 miles into its atmosphere. Saturn's rocky core is probably surrounded by ice. The density of the planet is so low that it would float on water, having a density only 0.685 times that of water, or an eighth the density of Earth. Saturn has a strong magnetic field, though twenty times weaker than Jupiter's, as established by the Pioneer and Voyager probes in 1979. Its magnetic axis bizarrely equals its rotational axis.
Saturn's Great White Spot was discovered by the legendary comedian and film star Will Hay (b. 6 December 1888, Stockton-on-Tees, d. 18 April 1949, London, in his Chelsea flat). He had a home-built observatory in his garden in Norbury, and was a member of the B.A.A. Saturn Section, and made his discovery on 3 August 1933. During the Great White Spot, an event occurring only once every Saturnian year, temperatures drop to -190°C and clouds of frozen ammonia track across the planet at 900 mph. Far stronger in effect than Jupiter's Great Red Spot, this is the biggest storm in the Solar System. The Great White Spot was probably caused by heat from the Sun and from deep within Saturn itself, driving huge convection currents through its atmosphere. Great White Spots occurred in 1876, 1903, 1933, 1960 and 1991.
Saturn has its equivalent of Northern Lights: a rare form of hydrogen, consisting of a positively-charged group of atoms, has been discovered on Saturn, using the UK infra-red telescope on Manua Kea HI. The highly reactive hydrogen is made by particles streaming through the atmosphere from the Sun, indicating the presence of an infra-red aurora. This phenomenon has also been detected on Jupiter.
Saturn is surrounded by a dramatic system of seven rings of which three are visible from Earth. All form exact circles, and are precisely level; both features unique in the solar system. Of these the central ring is the brightest and widest, 16,000 miles. The main ring system is 170,000 miles wide, but extremely thin, 10 miles, and consists of millions of lumps of ice and rock, orbiting the planet at tens of thousands of miles per hour. These lumps are probably the debris from former moons of Saturn which strayed too close to Saturn's gravitational pull. The 1,700-mile gap between the first two rings is known as Cassini's Division, after the French astronomer who discovered it, while the gap between the second and third, innermost, ring is called Crepe Ring. All the rings exist outside Saturn's "Roche limit". Flybys of Saturn by Voyager and Pioneer revealed more rings (F Ring), shepherded by satellites on either side, and showed that some of the rings were actually many ringlets braided together.
At the planet's two equinoxes, which occur every 14-15 years, the rings appear edge-on to the Earth due to Saturn's 26½° inclination, and appear to disappear for awhile. Since the rings are brighter than the planet at this time Saturn becomes far duller. Galileo's observations of Saturn from 1610 coincided with an approaching equinox of the rings so that at first there seemed to him to be three planets at close vicinity, and then, two years later, only one. This caused him to write, "Are the two lesser stars consumed after the manner of solar spots? Has Saturn, perhaps, devoured his own children?"
The glyph of Saturn symbolises the cross of matter taking precedence over the crescent of soul, the same two symbols as that of Jupiter, but inverted, representing the principles of contraction and limitation. It has been identified with the reaping hook of the god Cronus, or Time, the Grim Reaper.
Saturn was named after the father of Zeus (or Jupiter), Cronus, the Greek god of time and mundane time-cycles, who was the first ruler of Olympus. Saturn was an ancient Italian deity, god of agriculture, founder of civilisation and social order, who, after his dethronement by Jupiter, fled to Italy and reigned during their Golden Age, and who was remembered for his benificence by the feast of Saturnalia. Saturn is Santa Claus as well as Father Time and the Reaper. The planet was called Seb by the Egyptians, Seb meaning Time. In Moslem Persia, Saturn the planet protected cut-throats.
Saturn may be identified with the Jungian archetype, the Senex. Usually depicted as a male, the Senex is the part of the personality reflecting the wisdom of old age, such as that of our "elders". Mythological figures representing the Senex include the wizard Merlin.
Saturn's astrological principle is formative, through restriction, discipline, rigidity. It seeks social order, structure, planning, regulation, controls, material and social security "from womb to tomb", and imposes and enforces law and order. It can be seen to be strongly disciplinarian, intolerant, extremist, and tends to be projectionist, isolationist, and to build "iron curtains". Saturn is a masculine planet, despite being associated with the feminine Earth element, and connects with left-brain activity. Saturn has planetary rulership of Saturday. It is the day house ruler and esoteric astrology ruler of Capricorn, and night house ruler of Aquarius. It had no rulership in the Greek pantheon.
Saturn was originally the Greater Malefic, symbolising the wrathful God of the Old Testament, the Wise Old Man, and also the Tyrant. Saturn is like a strict parent and its effect is to limit and test. Saturn's ring system can symbolise the "ring-pass-not" of occult teachings; crystallised in graphic representation of its principle of limits and boundaries.
Saturn's significators are: consolidation, conservative approach, constriction, fears and frustrations, emotional repression; sense of inadequacy; inhibitions; urge to throw up barriers, either physical or psychological, to prevent unwanted intrusions; our ability to pursue well-defined aims with discipline and concentrated effort; our need for well- structured foundations to counteract adverse influences and effects.
Saturn takes 2½ years to travel through each sign of the Zodiac, and returns some 29½ years later. Therefore we experience a Saturn return when we are approaching the ages of 30, 60 and 90. These periods in our lives are recognised as extremely important times of change and reassessment.
Since Saturn lies between the 'inner' planets of the Solar System and the 'outer' planets that symbolise higher aspects of consciousness, Saturn represents a level of awareness that must precede a further evolution of consciousness, and is the timer of when such transcendence can take place.
THE MOONS OF SATURN
Saturn is known to have thirty-eight satellites, and there are undoubtedly more. The most recently discovered dozen or so of these (to
2005) are only 2-19 miles across, in irregular tilted orbits, and as they fall in several clusters could be remnants of larger smashed satellites.
Saturn's 31st known moon was discovered on 5 February 2003. S/2003 S1 is about 5 km wide and occupies a highly inclined and eccentric orbit that
averages 19.1 million kilometers from Saturn and takes 989 days to complete.
In 2004, the Cassini spacecraft found two small moons, possibly the smallest bodies so far seen around the ringed planet.
The moons are approximately 2 miles and 2.5 miles across and are located
between the orbits of two other saturnian moons, Mimas and Enceladus, rather
than within gaps in the rings as expected. They are provisionally named S/2004 S1 and
S/2004 S2. One of them, S/2004 S1, may be the object spotted by Voyager
23 years ago, then called S/1981 S14. On 1st May 2005 Cassini found
another moon, its 7th discovery since slipping into orbit around Saturn on 1
July 2004. S/2005 S1 is just 4 miles across, and orbits within the
Keeler Gap in Saturn's outer A ring.
The rings of Saturn are thought to contain further moons, and up to twenty small undetected moons could orbit close to them.
Titan was the first of Saturn's moons to be discovered, by Christiaan Huygens, on 25 March 1655. He noted that Saturn was "surrounded by a thin ring not adhering to the planet at any point and inclined to the ecliptic", and found Titan to have a revolution period of nearly 16 days (now given as 15.945 days).
Titan dominates Saturn's satellite system and is larger than any other known moon apart from Ganymede (and possibly Neptune's Triton), with a diameter of 3,201 miles. It has a surface temperature of -180°C. Titan is unique among moons in the Solar System in having a dense atmosphere, containing mostly nitrogen. In 1998, the European Infrared Space Observer (launched 17 November 1995) was announced to have discovered that Titan's atmosphere has water vapour in it. It also contains hydrogen cyanide, carbon and oxygen, so the total composition is thought, fascinatingly, to mirror the primeval soup of life-forming chemicals that preceded life on Earth. It comprises half rock and half water-ice. It may contain seas of liquid hydrocarbons and solid highlands of ice and rock. One area of Titan's surface is visible on telescopic images obtained in 1999 and could be a sea of liquid methane or ethane. Ethane smog might condense and rain onto Titan as black liquid.
It is thought that comets dumped water on various planets and moons, probably in the form of snow. Ultaviolet sunlight penetrating Titan's haze appears to be producing complex organic chemicals there. Titan orbits Saturn at a mean distance of 759,385 miles. A torus of hydrogen atoms surrounds Saturn extending between Rhea and Titan, and Titan is believed to be the source of the hydrogen supply.
The Cassini spacecraft was named after Jean-Dominique Cassini (b. 8 June 1625, Nice, in Perinaldo; d. 11 September 1712, Paris), the French-Italian astronomer who discovered four of Saturn's moons. It was launched, after some delays and postponements, on its seven year journey to Saturn, from Cape Canaveral at 0443 EDT (0943 BST) on 15 October 1997, bearing the space probe Huygens, built by the European Space Agency at a cost of £267 million. Its mission was to study Titan, in a bid to develop biologists' theories about the evolution of life on Earth by studying its own chemical cycles. To get there, Cassini
gained momentum by a flyby of four planets: Venus (on 30 April 1998 and 29 June 1999); Earth (18 August 1999 - the counter to the thrust will have delayed the onset of the new millennium by a fraction of a second); and Jupiter (15 January 2000 and 30 December 2000).
After arriving on 1 July 2004 at a distance of 211,000 miles, Saturn's magnetic field
was measured, using a device developed by Imperial College, London, and
preliminary snapshots taken on a camera specially devised for the purpose by Queen Mary and Westfield College
showed the surface in surprising detail, considering the interference from Titan's
smog-ridden atmosphere. The surface included straight, curved, and round surface features, suggesting that the
moon had been geologically active. Much more data was gathered during
Cassini's 70 orbits of the planet and its 45 swings past Titan.
On 14 January 2005, Cassini's module Huygens went into freefall towards Titan. It
was re-activated as it parachuted through the orangey fog of the moon, and
sent back 2½ hours of data, including atmospheric temperatures, pressures, chemical composition, electrical discharges, wind speed, and other
characteristics. Touchdown occurred about 1334 hr Central European Time (0734 EST),
on solid ground. Its final thirty minutes of were spent studying the moon from its surface, which could be solid or oceanic.
About 350 images were recorded in all, and mission scientists were left in awe
of Titan's revealed landscape. One view showed what appeared to be drainage channels flowing into
a shoreline. Another image showed a muted landscape of flat terrain, occasionally
interrupted by unidentifiable boulder-size objects.
The mission is due to end in late 2008, after 80 orbits.
Environmental protesters delayed Cassini's 1997 launch, concerned about its power source, which like other space missions, uses the radioactive decay of non-weapons-grade plutonium. This emits alpha rays to produce heat, which is converted into electricity to provide propulsion and power. The Titan IV rocket used to launch Cassini has a one in 20 failure rate, and there were fears that if there was a 1% error in its computer program it could graze Earth on 18 August 1999 flyby, with disastrous consequences. This flyby almost coincided with the total eclipse of the Sun by the Moon on 11 August, which some identified with doom laden Nostradamus predictions. The final decision to proceed with the mission, which had cost an estimated £2.1 billion, came from the White House only a fortnight before the launch, which was successful.
Iapetus and Rhea
The second moon to be discovered was Iapetus, found by Cassini in 1671. It had a revolution period of 79.331 days. Cassini also observed that "one part of his surface is not so capable of reflecting to us the light of the Sun which maketh it visible, as another part is". He was also the discoverer of Dione, Tethys and Rhea. The two toned surface of Iapetus was confirmed by the Voyager encounters. The dark region is called Cassini regio, and its dark carbonaceous material probably came from the moon Phoebe, following a projectile hit. The lighter material is thought to be a deposit of impure ice.
From all this it was deduced that the rotation period was captured or synchronous, keeping the same hemisphere turned permanently towards Saturn, as the Moon does to Earth. Tidal friction is responsible for this and all major planetary satellites behave in the same way. Iapetus is inclined at 14.7°. It is 2,213,363 miles from Saturn and is 907 miles in diameter.
Rhea, the second largest satellite, is 327,557 miles from Saturn, has a day period of 4.518 days and a diameter of 951 miles. It is heavily cratered but less bright than Tethys, and probably contains more rock than ice as it is denser than most of the moons.
Other discoverers include William Herschel who found Enceladus and Mimas in August 1789; William Lassell, who named Hyperion; and WH Pickering, who found Phoebe. Pickering also believed he had found another moon between the orbits of Titan and Hyperion, from photographs taken in 1899. He named it Themis and its orbit was published in part until 1960, but it vanished before the claim could be verified and now seems certain not to exist; it was probably an asteroid.
Mimas, Tethys and Enceladus
Mimas is the innermost of Saturn's classic satellites at a distance of 115,301 miles, and is normally given credit for holding Saturn's rings in place. Mimas causes the gap in Saturn's rings known as Cassini's Division. Its orbital period is 0.942 days. It has a diameter of about 244 miles and is dominated by a giant crater, one third of its own diameter, named Herschel in honour of Mimas's discoverer. The collision that caused this crater very nearly broke Mimas into a number of smaller pieces, because the density of Mimas is only 1.2 times that of water.
Mimas's surface is heavily cratered, representing heavy bombardment early in its history some 4 billion years ago. Most of the craters have Arthurian names: Arthur, Balin, Ban, Bedivere, Bors, Dynas, Elaine, Gaheris, Galahad, Gareth, Gwynevere, Igraine, Iseult, Kay, Launcelot, Lot, Mark, Merlin, Modred, Morgan, Pellinore, Percivale, Tristram, Uther..
Tethys (183,132 miles from Saturn) is probably of a similar age to Mimas as it is also scored with deep trenches and craters. It has a rift valley called the Ithaca chasma which is about 1,000 miles long. Its day is 1.888 of our days, and it is 659 miles in size. Tethys is co-orbital with two smaller moons, Telesto and Calypso (discovered 1980), 60° apart like the Trojan group asteroids co-orbiting Jupiter.
Enceladus has a complex geological history and must have been resurfaced in several stages, probably due to internal melting as a result of tidal forces, as its plains are thought to be less than a quarter of the age of the satellite. It has a perfectly smooth surface of pure water ice on one side, though the other is heavily cratered. 250 miles in diameter or more, it is 147,930 miles distant from Saturn and has a day equivalent to 1.37 Earth days.
Phoebe, which at 8 million miles from Saturn is its most distant moon, has an orbital inclination of 150°, and unusually has a retrograde orbit,
indicating that it may be the encrusted nucleus of a captured gigantic comet, probably a Centaur
type from the Kuiper Belt, and so a sister to Chiron, as the astronomer Patrick Moore proposes. Phoebe's low albedo (0.05) and darkish-red colour is similar to that of the class of
objects of primitive composition believed to be common in the outer Solar System; so Phoebe could be the first relatively unmodified primitive body in the outer Solar System to
have been photographed by a spacecraft. Cassini passed by Phoebe on June 11th 2004, its camera
scanning Phoebe's surface for 1 hour 10 minutes, revealing it to be heavily cratered,
indicating that its very dark surface may be masking an icy interior.
Its average density of 1.6 grams per cubic centimeter determine that it is a mixture of rock and ice in roughly equal
amounts. Its surface is a patchwork of water ice, unidentified organic
compounds and, uniquely in Saturn's system, frozen carbon dioxide.
Phoebe's elongation from Saturn can exceed 34' of arc and it is the only Saturn satellite to have a non-synchronous rotation period, 9 hours, compared to its revolution period of 550.4 days. It was also the first satellite to be discovered with the aid of photography.
The closest known moon to Saturn is Pan, found to exist on 11 Voyager 2 photographs taken on its close approach in August 1981. It was confirmed in 1991, having been announced on 16 July 1990 by Mark R Showalter. It was temporarily designated as 1981 S13. Orbiting within the Encke gap in the A ring, it has a diameter of about 12.4 miles, and its day is 0.57 long.
The other 17 known and named moons, in order of distance from Saturn, are Atlas (12 x 12 x 25 miles in diameter),
Prometheus (87 x 62 x 50 miles), Pandora (all discovered 1980), Janus and Epimetheus (1978), Mimas (1789), Enceladus (1789), Tethys (1684), Telesto (1980), Calypso (1980), Dione (1684), Helene (1980), Rhea (1672), Titan (1655), Hyperion (1848, by William Bond), Iapetus (1671) and Phoebe (1898).
Dione, is only slightly larger than Tethys but is far denser, the densest of Saturn's ice moons. It is 234,556 miles from the centre of Saturn and has a diameter of 696 miles and an orbital period of 2.737 days. Its surface is extensively cratered and has strange wisp-like markings which are probably the result of impact ejata in the form of an icy spray from its large crater, Amata, which froze on the surface. It is co-orbital with the small moon
Helene, discovered in 1980 but not from the Voyager results but by telescope.
Hyperion is irregular in shape. Iapetus has one bright and one mysteriously black hemisphere. All of them have orbits that are nearly circular and those within the orbit of Iapetus lie within 1½° of Saturn's equatorial plane.
Janus and Epimetheus are probably fragments of a former single body. The distance between their orbits is less than the sum of the diameters of the bodies. They meet every four years, but instead of colliding, their gravitational fields cause each to repel the other - a kind of game of cosmic musical chairs, as the two satellites then swap orbital patterns, so that the slower one becomes the faster, and vice versa. This will happen 7 times during each Saturn cycle.
According to Creation myth, Earth, or Gaia and her son Uranus (Heaven) bore the seven planetary powers on Mount Olympus, setting a Titaness and a Titan over each. Cronus (crow) was one of the first twelve Titans, the first race, and had rulership of Saturn, together with Rhea (Earth). Theia (divine) and Hyperion (dweller on high) ruled the Sun. Phoebe (bright moon) and Atlas (he who dares) ruled the Moon. Dione (divine queen) and Crius ruled Mars, Metis (counsel) and Coeus (intelligence) ruled Mercury. Themis (order) and Eurymedon (wide rule) ruled Jupiter, and Tethys (disposer) and Oceanus (of the swift queen) ruled Venus.
Other Titans included Iapetus (hurrier), who was the father of Prometheus, creator of mankind and brother of Epimetheus. Pandora married Epimetheus. Calypso was daughter to Oceanus, by Thetis. The majority of Saturn's moons are named after Titans and Titanesses, clearly, but Janus, the porter of Heaven, was a deity from ancient Roman times and earlier, whereas Enceladus was a giant who was defeated by Jupiter.
The moons would seem to be concerned with the struggle of integrating the physical world with the spiritual realm, through concerns of time and space.
Last updated 21 May 2005