Why Does a Week Have 7 Days?
By Konstantin Bikos
It's Monday and you are looking forward to the weekend. Why do you have to wait 5 days until Saturday? And how come the day after Monday is Tuesday and not, say, Sunday? You have an ancient people in modern-day Iraq to thank.
https://www.timeanddate.com/calendar/days/7-days-week.html
Saturn (Saturday)
Jupiter (Thursday)
Mars (Tuesday)
Sun (Sunday)
Venus (Friday)
Mercury (Wednesday)
Moon (Monday)