The birth of the Moon 4.6 billion years ago nearly destroyed the Earth.

Some 50 million years after the Sun formed, chunks of rock that had not been swept up into the planets were still chaotically flying about.

The birth of the Moon nearly destroyed the Earth

A world about the size of Mars was heading straight for the primitive and lifeless Earth.

At eight kilometres (five miles) a second they ground into each other. Rock became not just molten but flash vapourised; the ever growing circle of the impact glowed blue-hot and sprayed fragmented and superheated molten rock in all directions. Molten and vapourised rock plumed into space.

Such was the birth of our Moon, in just fifteen minutes.

Within hours the iron-deficient material became a beautiful ring around the Earth, and within days the Moon was forming.

Waterless world

The first Apollo samples returned to the Earth from the Moon showed a lack of water. This is a by-product of the ancient impact.

It heated the ejecta to high temperatures, so all the volatiles would have escaped to space as gases.

The Moon is rich in minerals

But how do we know when this happened? In lunar samples brought back by the Apollo astronauts the amounts of two elements - hafnium and tungsten - tell us.

Hafnium decays into tungsten with a half-life of nine million years. By measuring their ratios with that found in primitive meteorites, it can be estimated that the Moon was born just 50 million years after the solar system.

Thanks to Apollo, we know more about the Moon than we do about any other object in space, with the exception of our own planet.

We have the testimonies and photographs of those who went there. We have some 2,000 samples from nine sites, 382 kg from six Apollo landings as well as 0.3 kg from three Soviet automated sample return probes.

The Moon is deficient in iron, but rich in other minerals. The surface is composed of rocks containing oxygen, silicon and aluminium.

Four billion years ago, during the so-called pre-Nectarian period the Moon's crust solidified.

Since then, huge basins and ejecta blankets have covered most of the surface. Old, shattered rocks, brought back by Apollo's 15, 16 and 17 are relics of this period.

Many of the most pristine and spectacular craters we can see on the surface were formed relatively recently in the Moon's history.

Apollo 17 rocks tell us that the magnificent crater Copernicus was formed by an impact 810 million years ago. Tycho is only 110 million years old.

Everything needed for life is there

The Moon is all but changeless now. Almost all that happens are a few weak Moonquakes that occur at the extreme points in its orbit around the Earth.

The Moon has everything needed to sustain life

With the recent discovery of ice in the lunar dirt at the poles, there is in the lunar rocks everything required for supporting life, and many profitable industries as well.

To build the first Moon base we need take nothing with us. It's all there: aluminium, iron, hydrogen, helium and oxygen.

In 100 years time, the LunOx Corporation, based at the lunar South Pole, could be the biggest company on or off the Earth.

Because of its use as a rocket fuel and its easy availability, Lunar oxygen will be highly prized.

In fact whoever controls the Moon's oxygen will control the solar system.