Sunset Mirage

I was watching an episode of QI (fabulously informative series, wouldn't you have loved to have had a teacher like Stephen Fry?) and he had the contestants watch a sunset and they had to buzz when it had set. They all buzzed when it disappeared entirely, as would I. Apparantly though, what you see of a low setting sun is actually a mirage and the sun has actually set already. He explained it, something about reflective and dispersing light, but I couldn't put it in terms here. However, what I took away from this revelation is that I have been photographing mirages for a very long time!

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