From Ian Chapple
I couldn’t help feeling that mining minerals on Earth’s mini-moons would not be viable (21 April, p 48). If a 2-kilometre-wide asteroid is worth $25 trillion ($25×1012), surely a mini-moon one-thousandth of the diameter of such an asteroid (and therefore one-billionth of the volume) would only be worth $25,000 ($25×1012×10-9).
There does not appear to be any way in which the value of the minerals found on such a small moon could possibly justify the expense of getting there and bringing it back. Or am I missing something important?
Rijswijk, The Netherlands
