The Moon Is The Ninth Planet

Written with the help of Google Gemini

We grew up knowing the Solar System held nine planets, but then we were abruptly told we only had eight. This loss occurred in 2006 when the International Astronomical Union (IAU) set new criteria for planethood. While Pluto was spherical and orbited the Sun, it failed the critical test: it had not gravitationally cleared the neighborhood around its orbit. Pluto orbits within the Kuiper Belt, a crowded zone of icy debris, proving it is just one of many large objects out there.

Now, let's turn that same objective logic toward our Moon, and the true orbital dynamics reveal a path to having nine major planets once again.

The Moon Orbits the Sun

The profound irony lies in the history of language: The thing we call the Moon, the single object that gave the name to every other satellite in the universe is, itself, not a moon at all. For the entirety of civilization, the single "moon" humanity knew was the only object in the entire solar system that fails the physical test of orbiting its planet.

If the object we call the Moon were actually a moon like all of the hundreds of moons orbiting the Gas Giants it would orbit the Earth. Instead, we find the opposite is true, it orbit's the Sun.

The fundamental difference lies in the shape and position of the orbit. When the moons of Jupiter and Saturn orbit their planets, their paths are essentially large, closed circular orbits around the planet, much like the planet's path around the Sun. They go around and around. In sharp contrast, the Moon never goes in a circular path around the Earth. Its path is always convex, it always curves inward toward the Sun and never loops.

This means the Moon is primarily bound to the Sun's gravity. The Moon's motion is best defined as exclusively orbiting the Sun, with the Earth merely acting as a massive perturbation, causing the Moon to wobble and switch places with the Earth along their shared convex path around the Sun.

The Ecliptic Clue

Further proof lies in the Moon's alignment in space. The Moon's orbit is always within five degrees of the Ecliptic Plane, the very plane on which all the planets orbit the Sun. Because of this alignment, the Moon always appears to travel along the Zodiac (the band of constellations followed by the planets), making it behave just like the other Sun-orbiting planets, not a moon of the Earth.

The Moon: The Ninth Planet in a Dual Planetary System

Because the Earth/Moon system has cleared its orbital neighborhood (unlike Pluto), and because the Moon is exclusively orbiting the Sun, we can elevate its status. The Moon is a large rocky world that should be seen as a companion planet to Earth in a binary planetary system.

Considering no other inner planet even has a moon except for the 2 tiny irregularly shaped satellites of Mars, our Moon's massive size qualifies it as a binary planet. Venus is 95% of Earth's diameter, Mars is 53%, Mercury is 38%, the Moon is 27%, the now dwarf planet Pluto is 18.5% and Pluto's dual planet Charon is 9.5%, while the two tiny satellites of Mars combined add up to only two ten billionths of 1% of the Earth's mass. The Moon's size combined with its shared orbit around the Sun with the Earth classifies the Earth/Moon pair as a dual planetary system like Pluto and Charon which are clearly dwarf dual planets because the barycenter of their dual orbit lies outside Pluto, while the barycenter of the Earth/Moon pair is about 1/3 of the way inside the surface of the Earth which means it is technically not a dual planet according to common consensus.

The Final Count

By this physical definition, the traditional planetary count is wrong. If we rely on absolute objective truth where objects with Sun-dominated, non-looping orbits that have cleared their path are planets, the Solar System is currently home to nine major planets orbiting the Sun, five inner rocky planets (Mercury, Venus, Earth, The Moon, and Mars), and four outer gas/ice giants (Jupiter, Saturn, Uranus, and Neptune).

The Moon is not a satellite; it is part of a dual planetary system that orbits the Sun like Pluto and Charon. It is time to retire the outdated textbooks and get our ninth planet back.