A multitude of moons to make men mad

It was thought of old that our only earthly moon, as its Latin name implies, might make men lunatics

It was thought of old that our only earthly moon, as its Latin name implies, might make men lunatics. Thus does Milton write about chaotic "demoniac frenzy, moping melancholy and moon-struck madness" in his Paradise Lost and thus, too, Othello's feeble excuse for killing Desdemona:

"It is the very error of the moon; She comes more nearer earth than she was wont

And drives men mad."

So imagine the potential mental state of planet Uranus: it has no less than 15 moons. Two of these, Titania and Oberon, were noticed as early as 1787. Then Ariel and Umbriel appeared in 1851, and Miranda almost a century later in 1948.

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The other 10 were children of the space age: Ophelia, Cordelia, and Juliet; Belinda, Portia, Rosalind and Puck; and Bianca, Cressida and the aptly unfortunate heroine of The Moor of Venice, the ill-fated Desdemona.

As it happens, 13 of the moons are named from characters in Shakespeare; only Belinda and Umbriel are not, being taken from The Rape of the Lock by Alexander Pope.

Uranus is four times larger than the Earth, with a diameter of 32,000 miles. Like Jupiter and Saturn, it does not have a solid surface, but a squishy 6,000-mile-deep mantle of liquid water laced with methane and ammonia ice. Its atmosphere comprises hydrogen and helium, topped by an icy cloud of frozen methane.

But the strangest thing about Uranus is its orientation. Instead of its axis being "vertical" as Earth's is - roughly at right angles to its plane of orbit - Uranus lies on its side, with its axis almost "horizontal". As it proceeds in its 84-year journey round the sun, each pole is first exposed to continuous sunlight for 42 years, and then languishes in seeming endless night for the other half of the Uranian "year".

If you were to stand at the Uranian north pole in "summertime", you would see the overhead sun revolving in a small circle around the zenith every 17 hours - the length of a Uranian "day".

As the planet advanced towards its equivalent of Earth's September equinox, the sun would gradually spiral downwards in the sky, eventually to skim in a circle round the horizon before disappearing for nearly half a century.

Being 1,800 million miles from the sun, Uranus receives only a tiny amount of solar radiation, and this makes Uranian weather rather boring. With little or no solar heating, there are few, if any, storms, and the mid-latitude winds, blowing steadily at between 100 and 300 m.p.h. from east to west, are driven almost entirely by the rotation of the planet Uranus itself.