REMEMBER I had promised you a discussion on the remaining moons of the Solar System? Well, as you know there are about 100 of them in all. But it does not mean that we will require as many discussions to describe them all. We can lump them into a few, in fact two broad categories. Firstly, the rocky ones, secondly, the gaseous, or the ‘ chemical ‘ ones.

You already know that many of these moons, in fact most of them, are asteroids — those chunks of the rocky, uneven pieces of material that, in the course of their wanderings, came too close to one planet or the other and were promptly ‘arrested’ by them to become a part of the planetary neighbourhood. In short, these moons are the captured asteroids. The asteroid belt, housing them initially, lost them forever.

Some of the moons could be ex-comets stripped of their gases and other icy materials due mainly to the Sun’s persistent heat, howsoever faint and mellow. These moons are between one and three billion years old. After their departure from their real home, and thanks to their promotion, they are now called moons. As the interlopers misbehaved with the ‘asteroid rules’, they lost their place among the friends of the old. But I don’t think that they would have any objection to the accidental up gradation, since they now belong to the higher category as a natural consequence! Let us call them ‘ inter planetary ‘ objects. Nobody calls them asteroids anymore, though such moons still look a lot like asteroids.

But let me quickly reiterate that these little moons, or moonlets, are not round but elongated and uneven in shape despite the lapse of many billion years. This is on account of the fact that their gravity is not strong enough to chip away the rough edges and the protruding, or outlying portions to the extent that they become round like our own moon. What really happens is that gravity, as a result of the forces unleashed by it, pulls inwardly the mass lying outward. This leads to the shape becoming round and round until it becomes a ball, like all planets or stars and main moons. But for the new, later-day moons it was not easy to assume a round shape. For one their gravity is too little, in fact negligible to change their shape. Further, when they shifted into the new realm they had already formed the shape they were in. Remember that they were full-fledged asteroids or comets before becoming moons.

The one interesting things about these moons are those countless, tens of thousands of craters that come in all shapes and sizes. That is not all, the moons have other features that are caused by either the rolling pieces of rock smashing on their surface, or broken chunks of the exploding hunks. As some of these pieces roll across the surface, they drive a wedge called riles. Thus, many of the lunar features tell a different story about them to the prying astronomers. Many features on the surface of moons, as well as planets are caused by earthquakes and seepage of matter from deep inside these bodies, from fissures, fractures and faults. As the matter spews out, it forms valleys and even mountains (or islands in the seas) which may take a while to be crowned with flora and even thick forests as in the case of Earth.

Like Earth’s moon metamorphosised, but not much. That is because there is no erosion on these moons. I mean, no air, water, or dew but (in some cases) plenty of sunshine. Our own moon is a vast body of dry, arid ‘moonscape’ with not a hint of moisture. It keeps the same face towards the Sun (or Earth) with intense heating on the sun side and freezing cold on the permanent dark side (called arrested motion). That is because there is no air at all which may help reduce temperature by mixing hot with cold air. For this reason alone, any effort to colonise our moon would not be successful. Although many other factors would make the landing quite practicable, the actual colonising is nearly impossible.

Although moons offer plenty of real estate for earthlings to romp around, conditions on their surface are far too inhospitable for us to populate them even in our dreams. That is why no one dreams of a life on the moons! But that is what they said when Americas were discovered (1492 ).

Do you know that when television was invented back in the 1930s and became accessible to people in the 1940s and early 1950s, they said that it would die its own death, and some even refused to buy them! By the way the first person to appear on TV was Adolf Hitler, as he performed the opening ceremony of the Berlin Olympics (1936).

Any discussion on the chemical (or gaseous) aspects of the Solar System’s moons would stretch us beyond the space permitted. So, why not keep it for the next time when I shall not only end the topic but resume discussion on the long pending debris of the Solar System.

Until then good bye and God bless.