You are here

Moon and Antares

StarDate: 
September 19, 2015

In the modern world, it’s almost impossible to not know the correct time. GPS satellites transmit the current time to phones, wristwatches, cars, and just about everything and everywhere else.

Before the invention of mechanical clocks, though, people often told time with the help of the stars. In ancient Egypt, for example, they used about three dozen stars that were spaced evenly across the sky.

The stars are known today as “decans” — from the Greek word for 10 — because about every 10 days, a new one would rise into view in the dawn sky, while another dropped from sight in the evening sky.

As the night rolled on, the decans would rise at fairly regular intervals. As a new one rose, it marked the beginning of a new “hour.”

Even though the specific stars changed from season to season, the Egyptians used the same number of stars as decans every night of the year. That meant the hours were longer during the longer nights of winter. Still, the system was a reliable way to mark the passage of time — with the help of the stars.

Egyptologists aren’t sure which stars served as decans, but many of them almost certainly were among the brightest stars in the sky. One likely candidate is Antares, the orange heart of the scorpion — a constellation recognized by the Egyptians, by the way. And tonight, the star stands directly below the Moon as night falls — moving with the clockwork precision of the heavens.

 

Script by Damond Benningfield, Copyright 2015

Get Premium Audio

Listen to today's episode of StarDate on the web the same day it airs in high-quality streaming audio without any extra ads or announcements. Choose a $8 one-month pass, or listen every day for a year for just $30.