History · Level 1 · 176 words
Why a Week Has Seven Days
Original passage © Studio AM, written for Fluency.
A day is the earth turning once. A year is the earth going around the sun. A month is close to the moon's round of changes. These units come from the sky. You can see them.
A week is different. Nothing in nature takes exactly seven days. So where did the number come from? The answer goes back to ancient Babylon, more than three thousand years ago. Sky watchers there counted the lights that moved against the fixed stars. They found seven: the sun, the moon, and five points we now call planets. Seven moving lights, seven days.
The idea travelled. It reached Greece, then Rome, and Roman names for those lights became names for the days. Some of them are still in our week. Later, other peoples replaced some Roman names with their own gods, which is why the English days sound less Roman than the French or Spanish ones. The count of seven never changed. A week is not a piece of nature. It is a very old habit that we agreed to keep.
Source: Written for Fluency. Original passage © Studio AM, written for Fluency.