Ancient Egyptians measured the first hour, and changed how we related to time

• However, some time measurement units that derive from astronomical phenomena are quite easy to explain and likely were independently observed in many different cultures across the world.
• One of the most ancient written traditions, Egyptian hieroglyphic texts, gives us new insight into the origin of the hour.

Time in Ancient Egypt

• The Pyramid Texts, written before 2400 BCE, are the earliest writings from Ancient Egypt.
• Included in the texts is the word wnwt (approximately pronounced “wenut”), and the meaning-hieroglyph associated with it was a star.
• But around 1210 BCE in New Kingdom — the period of ancient Egypt between the 16th and 11th centuries BCE — the link between the number of rows and the word wnwt is made explicit.

Astronomical instructions

• One temple, the Osireion at Abydos, contains a wealth of astronomical information, including instructions on how to make a sundial and a text describing the motions of stars.
• It also contains a star table of the coffin type where, uniquely, the 12 rows are labelled with the word wnwt.
• By the New Kingdom, there were 12 night-wnwt and also 12 day-wnwt, both clearly time measures.
• First, although there are 12 day-hours and 12 night-hours, they are always expressed separately but not together as a 24-hour day.

Timekeeping stars

• The ancient Egyptians chose to use the bright star Sirius as a model, and selected other stars based on their behavioural similarity to Sirius.
• The key point seems to be that the timekeeping stars disappeared for 70 days each year, just like Sirius, even though the other stars were not as bright.
• Depending on the time of year, between 10 and 14 of these stars are visible each night.