Looking at the moon through a pair of binoculars, you really get a sense of how round and big it is. And yet how small when you see its craters silhouetted against undiluted darkness and realise how large a portion of the surface each one covers. Then there are the seas: great ash coloured bruises. All this seems obvious. I’ve just described the moon — nothing special here, you’ve seen it a thousand times — but think how obscure this really is: a speck of dust orbiting a speck of dust orbiting one of 300 billion stars in at least 100 billion galaxies. Viewed from anywhere else in the universe, it is essentially another dark patch of sky… but luminous to us. If we are not astounded by such a sight, we should learn how to be.