THE middle of the road planet is also the “middle one” in every way. A sedate loiterer, careering in the middle of the Solar System, planet Saturn has five inner and three outer planets to serve as neighbours in the pretty crowded system (I still regard Pluto as a planet and not a planetoid).

Also regarded as a classical planet, Saturn has been known to mankind before the discovery of those that required at least an optical telescope, not to speak of the right kind of mathematics to work out their potential presence in the skies.

The glittering prize of Saturn and its claim to fame continues to be its lovely ring system. Though another claim is no less potent: the planet’s numerous moons — many dozens of them, (maybe some more) that lie hidden inside its irrepressible ring system. Their orbits around the master planet are no less interesting. They orbit independent of the ring system.

But surely the moons are prodded and nudged by the rings that house them. And I can see collisions galore; smaller pieces ramming into the bigger ones and, in the bargain hurting themselves before disappearing, digging those ominous craters on the face of the boss.

Understandably, there is wide space between individual moons and the debris forming the ring system. The space is wide enough for the moons to roam freely but not without some, if occasional obstruction as stated above. Most of these so-called moons are not moons at all: they are captured asteroids of irregular shapes which could not coalesce into round shapes as large moons do, but remained in mountain-like shapes.

For a long while Saturn was considered the limit of the Solar System; until 1781 when William Herschel, the German musician living in England discovered planet Uranus, which instantly earned him the most coveted prize of royal proximity. He was employed as Astronomer Royale in the court of King George V. Soon he ended up discovering two moons of the planet (Oberon and Titania).

There is much more to Saturn than meets the eye. But for present we shall confine ourselves to the moons of this planet — in fact, some of the moons, of the portion of the Solar System so far. For the other moons, let us first get over with planets from Uranus to Pluto, then their moons).

Most of the icy moons of Saturn are tiny, and very cold for their distance away from the Sun. But, of the lot, Titan is large enough to have oceans, if frozen. With a diameter of 5150km it is larger than planet Mercury. That gives you an idea of its enormous size. Titan, together with Jupiter’s Ganymede is large (and pretentious!) enough to cool over the billenia(eh!) and also have an atmosphere, probably containing elements associated with living organisms like hydrogen, oxygen, carbon and nitrogen, as on the Earth.

Titan’s atmosphere is far denser than that of Earth’s. Its surface temperature is -180C. However, some astronomers feel that some organic (life-giving) molecules might have rained onto its surface providing Titan with some form of life in the early ages of its history (say, in the first couple of billion years or so). Its orange coloured clouds are more than 250km deep with an even deeper haze layer which makes the observation and study of the moon very difficult. The question of life, then what kind of life, is a question that has defied an answer thus far.

The large moons of Saturn are composed of ice mixed with a great deal of rocks, making them somewhat Earth-like. Virtually all of them have crater marks, some others (notably Mimas) have numerous craters, probably more than the Earth’s Moon. It has borne the brunt of meteor, comet and asteroid bombardment like little else.

Enceladus, same size as Mimas, however, shows a much different surface. It appears that it is a much younger moon, showing much more, and relatively recent, ‘geological’ activity. Dione is another one that shows more recent periods of activity. It has a diameter of 1120km and was discovered by Cassini in 1684.

Some other prominent moons of the Solar System so far may be summarised as follows: Phobos and Deimos (27 and 15km); these are Mars’ famous moons; Io, Europa, Ganymede, Callisto (3640, 3130, 5270, 4840km respectively), they belong to Jupiter and are popularly called the Galilean moons after the guy who first saw them (Galileo Galilae, who else!).

Then there’s Saturn’s Atlas 40 km, Pandora 100km, Tethys 1060 km, Calypso 30km, Rhea 1500km, Hyperion 400km, Iapetus 1460km and Phoebe 220km and so on. These are not essentially the largest of moons, nor the whole lot of them. But prominent ones in one way or another. The list also gives you an idea of how small, tiny moons make do with the large ones and survive. Of course it does not include our own ominous moon. It has been set aside for a separate discussion, which will involve many of those factors that is common with all the other moons, and even asteroids; as also their history and ‘moonology’.

When I was very young, a long while ago, and had just taken up astronomy, it came to me as a surprise that the Solar System had as many as 60 odd moons. Since that time eons ago, I have come to learn of many wonderful things that, to this day, leave me agog with amazement. That every single thing in the universe has no parallel; just as if there is a cat to consider so there is a tiger, a lion, an ocelot, a cheetah, etc., all distinctly separate and different from one another yet so much like each other. Look at insects, trees, humans, fishes, animals, birds and the components of air that we inhale and exhale. Then those germs and bacteria, all of them nothing but full of marvels and amazement. So is astronomy.

Now I wonder where these items came from and why: after the Solar System formed was there so much raw material left that it should coalesce into a hundred moons, a million asteroids, a billion comets, a trillion meteors — all of them independent of one another? The fact is that all of them combined do not add up to more than a very small portion of the mighty Sun. The marvel is that they are so many, and so unique. Go on and think about it! As insisted by some friends, next piece belongs to astrology; and this maverick’s science.

The writer is a professional astronomer and a former head of PIA Planetaria. He can be reached at astronomerpreone@hotmail.com


Do you know your ‘space’?

IN February 2013, an 11,000-tonne meteor exploded above the Russian city of Chelyabinsk, injuring more than 1,000 people and causing major property damage. Scientists later found that the shockwave created by the explosion was so powerful, it travelled around the Earth twice

Who owns space?The 1967 UN Outer Space Treaty declared that Earth’s moon and other celestial bodies may be used only for peaceful purposes, and no part of space can be owned by any government, business, or person. That hasn’t stopped some entrepreneurs from selling land on the moon!

Tears don’t fall in space. In a 2013 video, International Space Station commander Chris Hadfield showed that, in zero gravity, water from crying forms a ball on your eye that just keeps building up until it spreads across your face — or you wipe it off.

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