The answer to this question - which we've all surely asked ourselves at some time or another - is:
But let's start from the beginning. A book has been published with the intriguing title Who Built the Moon?, written by two pseudoscience'n'conspiracy wonks, Alan Butler and Christopher Knight.
The idea behind a 'built' moon has a certain superficial appeal: the moon helps stabilise the tilt of the earth, keeping it at the right angle to the sun, thus stopping it getting too hot or too cold for life to flourish. There's also the idea that the ebb and flow of tides (caused by the Moon) has various benefits and may even have played a role in the evolution of stuff that lives in the sea, which, lest we forget, is our ancestors.
Thus the book argues that the chances of the moon being the right size, in the right place etc. are too great for it to have come about by chance.
Oh, fuck off. This hoary old chestnut is basically the argument from design by another name.
The excellent site www.skepdic.com, run by philosopher Bob Carroll, lists some of the claims made about the earth, moon, sun, etc. It rightly points out that life would not exist if:
- The sun were just slightly farther away or half as powerful
- The axis of the earth were slightly different
- The moon were larger or closer or farther away
Plus lots more. There are quite a few ways of demolishing the idea that the apparent improbability of conditions being just right for life implies design, but the simplest is neatly summarised by John Allen Paulos in his book, Innumeracy: Mathematical Illiteracy and its Consequences:
'... rarity by itself shouldn't necessarily be evidence of anything. When one is dealt a bridge hand of thirteen cards, the probability of being dealt that particular hand is less than one in 600 billion. Still, it would be absurd for someone to be dealt a hand, examine it carefully, calculate that the probability of getting it is less than one in 600 billion, and then conclude that he must not have been dealt that very hand because it is so very improbable.'
Quite. Who Built the Moon? also makes mention of the pivotal (so to speak) role of the Moon in human history.
Plenty of cultures throughout history have attached supernatural powers to the moon: in times past people believed that staring at the moon could drive you insane, or that it triggered a transformation into werewolves. In modern times people still believe more crimes occur during a full moon, while 'biodynamic' farmers sow seeds according to lunar cycles in the belief that... well, who cares, frankly?
Of course, the fact that lots of people happen to believe stupid things doesn't make them important. And by now the various moon myths have been thoroughly debunked: check out www.snopes.com.
Undeterred by the fact that their arguments are a load of crap, the authors conclude that someone (or something) built the moon. But what's really breathtaking about this latest slab of ridiculous pop pseudoscience is the conclusion the authors reach about who did actually build the moon.
The authors reject God because if he built everything he wouldn't let earthquakes, tidal waves, plague, etc. happen. Ditto aliens, because they would have to come from so far away that they wouldn't be able to monitor the development of life on earth (if indeed that was their aim - the authors are a bit vague on this.)
So, the obvious conclusion is this: humans from the future came back in time and built the moon.
Occam must be spinning in his grave. The sheer stupidity of this idea - not to mention the inherent problem of humans not existing in the first place, and the logical impossibility of backward time travel - truly make this one of the classics of shite pseudoscience.
Come back, Von Daniken, all is forgiven.