Influence of the Planets and Etymology of Weekday Names in the Talmud

Background for Tractate Brahot 59b

Blessing of the Sun

The Talmud states that every 28 years the major solar cycle starts again (i.e. the sun is believed to return to the exact same “location” as it was at the creation of the world). It occurs during the spring equinox (in the Hebrew month of Nissan) in the “hour of Saturn” on the Tuesday evening that precedes Wednesday.

Hour of Saturn

As recorded by Rashi in Tractate Eruvin 56a, there was an ancient belief that every hour of the day was controlled by a different “moving star” [kochvai lechet] (to differentiate from the fixed stars). There were 7 “moving stars”: the Sun, the Moon and the five visible planets. The order of the “moving stars” for their purposes were as follows: Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon.

Each hour was controlled by a different “star”. The cycle of control repeated itself every 7 hours. The below graphic attempts to illustrate the hours of control. If we start counting the hours from nightfall after the Sabbath, the first hour of the night will be Mercury, while the first hour of the morning will be Sun. The first hour of the second day is Moon. The first hour of the day is also significant as it is said to have an influence on the entire day as well.

Etymology of Days of the Week

Therefore, someone born on the day of Mars during the hour of Mercury means they were born on Tuesday during the fourth hour of the morning. What is curious is how the “star” influence of the day has carried through millennia to the names we give to the days of the week:

In English, Sunday, Monday and Saturday still retain the Latin names of the “stars” while the other days were switched to the Norse counterparts. In Spanish, except for Saturday (Sabado) and Sunday (Domingo) which were changes as a result of Christian influence, all the other days of the week still retain their Latin “star” etymology.

Conclusion

Based on the above, when the Talmud states that the Sun returns to its original position during the hour of Saturn between Tuesday night and Wednesday, we know that it’s the first hour of the night and we also got a chance to learn the etymology of the weekdays based on the belief of the influence of the planets on our world that was utilized by the Talmud and later Rabbinic authorities.