As cool as that visual image sounds, from where you’re standing, the moon will look like the same white sphere that the late Neil Armstrong walked on 43 years ago (and in a spooky cosmic coincidence, it coincides with the astronaut’s Friday funeral). A “blue” moon simply means the second full moon that occurs in a calendar month (a full moon occurs every 29 days and our last one was on August 2). The phenomenon occurs around every two and a half years.The colour reference is a mystery, but when Elvis and Ella Fitzgerald sang about it, “Blue Moon” certainly sounded more lyrical and romantic than “rare calendar phenomenon”. If you really can’t face that cousin, don't stress. Clear some calendar space for July 31, 2015.