"It's probably hard to explain to a child who's seen nothing but a sand-filled wasteland all his life. But there's mountain ranges, various kinds of grass, wildlife you won't have seen before. It's a combination of those things that make it a nice planet."

The next question gives him some pause as he tries to work out exactly what's being asked. "Do you mean how to tell between the stars being small or far away, or how to tell you're even picking up on those options?"