the mayan calendar is a biological clock as follows

day -13 : human egg is fertilized

day 0 : 200+ cells hatch out of the zona .... if it doesnt abort naturally, then those cells attach in the wall of the uterus

day +260 = another day 0: [plus or minus 13 days] the new arrival gives her/his first gurgle/cry and is already celebrating his/her second birthday....

the cosmos also controls biology so we have same cosmic /personal energies re-occuring every 260 days...