T. S. Eliot had a feline friend endowed with many talents:
Macavity, Macavity, there's no one like Macavity;
There never was a Cat of such deceitfulness and suavity;
He always has an alibi, and one or two to spare;
At whatever time the deed took place, Macavity wasn't there!
Thus far, the cat's qualities are plausible. But when he claims that:
Macavity, Macavity, there's no one like Macavity,
He's broken every human law, he breaks the law of gravity,
then Eliot has gone too far. No one, but no one, is immune from gravity.
The force we experience as gravity is a consequence of a mutual attraction between our bodies and the Earth. It gives us that quality which each of us recognises as our "weight", which is in turn denoted by a number which most of us from time to time make efforts to reduce.
The figure we associate with our weight depends not only on our personal avoir- dupois, but also on the gravitational characteristics of this planet. In theory we could reduce our weight by living on a different one, and in general, the smaller the planet the lower would be the force of gravity upon its surface - although the density of the material of which a planet is made also plays a part. If life were virtual reality, a virtual voyage to a distant planet could be used to reduce one's weight quite painlessly.
From this point of view, the best locations are the planets Mars and Mercury. Gravity on both is a mere 40 per cent of that on Earth, so a 12-stone earthling might expect to feel as if he weighed only four and a half stone as he hopped across the rugged surfaces of these other worlds. There are disadvantages, of course: looking at the aspects of both environments, we find that Mercurian days are always boiling hot, and temperatures on Mars are usually well below freezing point.
Our 12-stone man, if transported hence to Uranus, would have his weight reduced immediately to 10 stone seven, and would tip the scales at much the same amount on Venus. On Saturn his weight would identical be to that on Earth, but on Neptune he would carry 17 stone, and on Jupiter a massive 31 stone. But by far the best weight-watcher's haven is next-door: if he could survive its lack of atmosphere, the average man on the Moon could hop around its surface like a two-year-old, since it would seem to him that he weighed just 27 pounds.