Cosmic Time: The Heavenly Origins of the World’s Calendars
- The Heavens
- What is a day?
- When do you cast no shadow?
- Does Earth rotate once a day?
- Why are there seven days in a week?
- What is a month?
- What is a year?
- Why do we have seasons?
- Does Earth orbit once a year?
- The calendar that took over the world
- The ancient Mesopotamian calendar
- The ancient Egyptian calendar
- The Jewish calendar
Cover Image Credit: Kristian Pikner via Wikimedia Commons.