There are 86 notches on the tablet, a number that has two special meanings. First, it is the number of days that must be subtracted from a year to equal the average number of days of a human gestation. This is no coincidence, says Dr Rappenglueck. It is also the number of days that one of Orion’s two prominent stars, Betelguese, is visible. To ancient man, this might have linked human fertility with the gods in the sky.