IF you remember, before being rudely interrupted yesterday by some funny-guy from Galway with an aerosol, Weather Eye was on a Cook's Tour of the universe to see if Voltaire had got it right. "Tout est pour le mieux," he used to say, "dans le meilleur des mondes possible." (All is for the best, in the best of all possible worlds.)
And indeed our Earth is not so bad. Jupiter, Saturn, Neptune and Uranus, for example, have no solid surface in the conventional sense; in each case, the outer layers of the planetary mass are fluid, and at their outer fringes they are bitterly cold, with temperatures between minus 150 and minus 220 Celsius. A visitor to these inhospitable worlds would sink deep into insubstantial quagmires, and never again would he or she be heard of. But let's home in on Saturn.
Saturn was the outermost of the five planets known to the Egyptians, Greeks and Romans.
It is easily visible to the naked eye as a bright and rather yellowy feature of the heavens, but when it came into focus in Galileo's telescope in 1610 it held a few surprises: "The planet Saturn", he wrote, "is not one alone, but is composed of three, which almost touch one another and never move nor change with respect to one another. They are arranged in a line parallel to the Zodiac, and the middle one is almost three times the size of the lateral ones."
Two years later, however, Galileo had an even bigger surprise when he aimed his telescope in that direction once again. He found that the two outer "satellites" had disappeared. "Does Saturn devour his children," Galileo asked, mindful of the nasty habit of the Roman deity of that name.
Saturn's mystery was unravelled after 40 years or so. Around 1657 its strange "two-handled teacup" structure was explained by Christian Huygens, who described "a thin flat ring surrounding the planet and not touching it". We now know that there are numerous rings, made up of vast numbers of icy particles, ranging in size from that of a tiny pebble to a large Mercedes, all whirling in strict formation around the planet like a myriad of tiny moons.
The largest ring is more than 100,000 miles across, but even the bulkiest is no more than half a mile in thickness. For this reason, when they are turned edgeways to us - as happens on average every 15 years or so - Saturn's rings seem to us to disappear. Hence the event in 1612 that gave rise to Galileo's panic.