There are 13 full moons in a year. The average menstrual cycle is 28 days, the same length as a lunar month. A year of 13 months at 28 days each gives you 364 days, one short of a solar…

Friday the 13th has been feared in Western culture for over a century. But the fear is surprisingly recent, historically shallow and built on a foundation that does not hold up to scrutiny. Underneath the horror movie imagery and the…