CNN
—
When it comes to bad luck, there are few superstitions as pervasive in Western culture as that of Friday the 13th. Like crossing paths with a black cat and breaking a mirror, the notion of a day that can bring misfortune is deeply embedded — even if believers can’t quite explain why.
There’s even a name to describe the irrational dread of the date: paraskevidekatriaphobia — a specialized form of triskaidekaphobia, a fear of the number 13.
While Friday the 13th may feel like a rare phenomenon, our Gregorian calendar means that the 13th of any month is slightly more likely to fall on a Friday than any other day of the week. It is not, however, a…