Question

Why does a week have seven days​

Answer 1

the main reason is :

Avid astronomers and astrologers, the developed a kind of horoscope around 500 where each day of the week was assigned to one of the classical planets – the seven celestial bodies visible to the eye. These are the Sun, the Moon, Mars, Mercury, Jupiter, Venus, and saturn

Answer 2

Hi!the week has seven days because the Babylonians, who lived in modern-day Iraq, were astute observers and interpreters of the heavens, and it is largely thanks to them that our weeks are seven days long. The reason they adopted the number seven was that they observed seven celestial bodies — the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn.