Answer:
Number seven was considered to be a lucky number in ancient
times. Before the invention of the telescope only seven planets were visible,
they were Mercury, Venus, Mars, Saturn, Jupiter, the sun and the moon.
Explanation:
The correct answer to this open question is the following.
The 'seven' was such an auspicious number in ancient cultures because those civilizations consider it as a lucky number or divine number that is also mentioned in the bible in the creation story of "Genesis", in the Old Testament. That is the first book of the Old Testament when it is said that God created everything in seven days. Of course, it is a metaphoric way to express it. Some researcher of the bible says that the number seven appears constantly in many of its books.
