China sets sights on mining the moon
Can we mine the moon? It seems imperative to do so.
The space-faring nations have ignored the 1979 outer space treaty, and last year the US's Space Act removed legal obstacles to extraterrestrial activity, and many people are gearing up to mine one of the most valuable substances that occurs in nature.
This extraordinary substance is the isotope helium-3, invaluable in ensuring the safety of nuclear power stations on Earth, and providing an all-powerful rocket fuel.
It is rare on Earth. It is found in troclotite, a metal of magnesium and iron, again rare but plentiful in the moon's crust.
All nuclear power plants react to produce heat. This turns water into steam that drives a turbine. Current nuclear power plants have nuclear fission reactors to split uranium. This releases energy, but also radioactive nuclear waste that must be stored indefinitely. For over 40 years scientists have been trying to achieve this.
But there are around a million tons of helium-3 on the moon's surface down to a few metres. This helium-3 could be extracted by heating the lunar dust to about 650°C before bringing it back to the Earth to fuel a new generation of nuclear fusion power plants.
A fully loaded spaceship's cargo base could power a quarter of the world for a year. This means that helium-3 has a potential economic value in the order of about £1-billion (R22-billion) a ton, making it the moon's most valuable commodity.
China's lunar exploration programme is proceeding fast, strongly attracted by the prospect of helium-3 mining. In 2013 China managed to land a lunar robot lander. The final stage of its current programme intends sending a robotic craft to the moon that will return lunar rocks to Earth.
Returning to the present, there are wonderful things to see in the night sky. The Milky Way itself is a marvel of strange nebulousness. No wonder some ancient Greeks thought it was milk, not a vast mass of billions of stars.
Another is the four moons of Jupiter. Look up at the striped, monstrous giant to see its four biggest moons in their extraordinary variety; Io, with its many active volcanoes; Europa, with an ocean beneath its ice, not to mention asteroid-battered Callisto and Ganymede.
Their discovery by Galileo around 1610 literally created observational astronomy, and was perhaps one of the greatest achievements in science.