Hi, new to the forums, nice to meet you folks, etc. Today the English wikipedia featured a picture of Tracy Caldwell-Dyson in the cupola of ISS(http://en.wikipedia.org/wiki/File:Tracy_Caldwell_Dyson_in_Cupola_ISS.jpg). In that picture the arc of Earth/space boundary is visibly distorted at the window edges and where the astronaut's forearm obscures the view. Looks a bit like capillary action, although it's probably symmetrical and only appears to distort towards one side due to brightness difference around those points. Anyway, last time I touched optics was in high school, and while I'd love to grok the how&why of the effect, I don't even know where to look for it. Is this due to diffraction? Something else? It bothers me to no end, and I'd appreciate any help here, be it an in-depth explanation, or just pointing in the right direction. Cheers chaps.