Number symbolism - Pythagoreanism, Numerology, Mysticism
https://www.britannica.com/topic/number-symbolism/Pythagoreanism
WEBThe Pythagoreans recognized the existence of nine heavenly bodies: Sun, Moon, Mercury, Venus, Earth, Mars, Jupiter, Saturn, and the so-called Central Fire. So important was the number 10 in their view of cosmology that they believed there was a tenth body, Counter-Earth, perpetually hidden from us by the Sun. polygonal numbers.
DA: 82 PA: 20 MOZ Rank: 98