"That light," said the Chaplain, "is it going up or coming down?" "It's coming down," said Lord Asriel, "but it isn't light. It's Dust." Something in… - Philip Pullman

Lyra sighed; she had forgotten how roundabout Scholars could be. It was difficult to tell them the truth when a lie would have been so much easier for them to understand.

As I understand it, the Holy Church teaches that there are two worlds: the world of everything we can see and hear and touch, and another world, the spiritual world of heaven and hell. Barnard and Stokes were two — how shall I put it — renegade theologians who postulated the existence of numerous other worlds like this one, neither heaven nor hell, but material and sinful. They are there, close by, but invisible and unreachable.

At one point he seemed to be showing the moon to Lyra, pointing up at it and holding her so she could see, or perhaps he was showing Lyra to the moon; at any rate he looked like a lord in his own domain, with nothing to fear and all the silvery night to enjoy.