It’s About Time

What’s a year? Why do we measure it in days and weeks? How do calendars differ? What’s the earliest known date? (Hint: It’s the year Egyptians invented the calendar.) Learn answers to these and other timely questions at Calendars from the Sky, a site developed in part with support from the National Institute for Standards and Technology’s Time and Frequency Division.

Go to: http://webexhibits.org/calendars