My doctoral school in planetary science had students from a mix of academic backgrounds, so we all had to take astronomy as geology classes. We all went together across town to the observatory to meet the somewhat elderly astronomy professor. When he opened his computer, the screen was filled with hardcore porn. We all sat in silence as he closed it and opened his presentation. He then started his talk, which featured a classical painting of the milky way coming from the breast of Hera. When the picture was on the screen he looked at it for a while, then said “mmm, I like this picture.”