Today I finally met Caolionn, after 5 years! (see here for an earlier post about her). She does look great. We had a coffee at a Starbucks in Geneva, a town near Fermilab. Caolionn is such fun! I had a memorable time with her, talking about the past and the present with an endless stream of jokes.
Driving to Geneva I had to stop my car to take a picture. These days the temperature is well below freezing around here, and these conditions favor the appearance of parelia (aka sun-dogs). I in fact saw them, and started screaming "look! Sun dogs there". And Caolionn did not understand what the fuss was about (she later explained my bad accent had suggested her I was talking about sand dogs, which she could not figure out why could be so exciting). I went as far as explaining the phenomenon to her, mocking her about the fact that a physicist should know what they are!
So here is one of the two parelia, barely visible just below the street lamp (it's the bit of rainbowish glow in the sky). I'm surprised I was able to pick it up, given the basic digital camera I took the picture with. Parelia are a rather rare phenomenon. They are formed when a particular kind of crystalline ice (I think hexagonal crystals) is borne in the atmosphere, and the sun's light is reflected preferentially at a particular angle (each color at a slightly different angle, thus the rainbow effect) by those which lie at the same angle above the horizon as the sun.
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