The Earth has got itself a new moon. The new satellite is temporary: it will leave again at the end of November. And it is very small, at just 10 metres across.

October's full moon will have some company this month now that a mini-moon is in Earth's orbit. Here's what you should know about the second moon.

Asteroids are ripe for mining. Some contain gold or platinum. Others could help make rocket fuel. When they're mini-moons, that's a prime opportunity.