Risu raised an eyebrow. "I do not play favourites," he said. "Except in one case, perhaps," he added as an afterthought, nodding in the direction of the photograph of himself and the blond witch on the edge of the desk.

"Besides, what if I am bad luck? Could be I'd send Hufflepuff into a ten-term losing streak if I support you, Jake," he said seriously, as doubt began gnawing at his mind immediately. He wouldn't put it past the Universe to play this kind of karmic trick on him - hadn't Friedrich Nietzsche said something to that effect? Gaze long into the cosmic abyss, and in return it'll punish your favourite Quidditch team? Risu shrugged to himself. Something like that.

"Ah, that's the tricky part. Due to the subtleties of spacetime," he continued with his lecture, "they are talking about both distance and time. Something, say, one lightyear away would have a distance from Earth of ten trillion kilometres. But you could also say that it has a distance of one year, as measured by the speed of light. Light, you see, is the calibrating factor between space and time. Information about events, for example, do not reach us faster than light, either."