Yesterday in "Weather Eye" we had the Great Dark Spot of Neptune; today we begin with the Great Red Spot, a pinkish "eye", large enough to swallow several Earths, that stares, Cyclops-like, from the lined face of Jupiter.
It bears many resemblances to an earthly hurricane, the clouds and winds circling around it counter-clockwise, but it is a centre of high pressure, not of low, and in contrast to our ephemeral disturbances it is known to have existed for at least 300 years. It is the largest storm in the solar system.
Jupiter, indeed, is something of a great celestial Texas: everything about it is superlative. Of the nine planets, its diameter is the greatest, its gravity the strongest, its days the shortest, and its magnetic field by far the most pervasive.
Jupiter's weather, moreover, is more violent and varied than any of the other planets; a Wagnerian extravaganza with massed choirs and perennial crescendos, in contrast to the gentle string quartet to which we might compare the behaviour of the elements here on Earth.
As in the case of Neptune, average temperature on Jupiter does not have a meaning as we understand the term. This planet, too, lacks a solid surface, its interior being gaseous or fluid virtually throughout its bulk, so that its outer atmosphere, mainly hydrogen and helium, merges imperceptibly into the very fabric of the world itself.
On the outer fringes of this atmosphere the temperature is a frigid -160 Celsius, a result of Jupiter's 500-million-mile distance from the sun; 60 miles down, the temperature is a tropical 40 degrees, and 600 miles into the depths it sizzles at over 2,000 degrees Celsius.
These high temperatures are caused by a mass of hot hydrogen in the deep interior, a great furnace that supplies the energy to drive the Jovian weather system; in contrast to Earth, where our weather is driven entirely by external energy from the sun.
Fuelled by this heat, great convective storms wrack the upper layers of Jupiter's atmosphere, causing towering thunderstorms lit by brilliant super-bolts of lightning.
As a consequence of its internal source of heat, Jupiter's polar regions are as hot as those at the equator. There is therefore no tendency for warm "air" to move from the equator towards the poles, or vice versa.
The weather consists mainly of broad multi-coloured bands of cloud, racing either west to east or east to west; these counter-flowing streams rub against each other, and great eddy-like twists and swirls lend a surrealistic exuberance to the undulating boundary separating them.