""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 the way he said it made Lyra imagine dust with a capital letter, as if this wasn't ordinary dust. The reaction of the Scholars confirmed her feeling, because Lord Asriel's words caused a sudden collective silence, followed by gasps of incredulity."