An Argument The Moon is a PLANET!

Quick Overview

The Moon meets all three criteria set by the International Astronomical Union (IAU) for an object to be classified as a planet, suggesting that the IAU's current definition is flawed because it explicitly excludes satellites, leading to the conclusion that the Moon should scientifically be considered a planet.

Key Points: The IAU's 2006 resolution defines a planet by three criteria: orbiting the Sun, having sufficient mass for hydrostatic equilibrium (nearly round shape), and having cleared the neighborhood around its orbit. The Moon satisfies criteria (a) (orbiting the Sun, as it orbits the Earth, which orbits the Sun) and criteria (b) (being gravitationally round), as it is more massive than Pluto and Ceres. The Moon fails criterion (c) because it is a satellite orbiting the Earth, which the IAU definition explicitly excludes via footnote (1) which lists only Mercury through Neptune as planets. The video argues that if the Sun (a star) were placed in the outer solar system, it would fail criterion (c) due to being orbited by captured objects, yet the IAU definition would still label it a planet. The author suggests the IAU's definition is arbitrary and culturally biased, noting that if the definition were purely scientific (not excluding satellites), the Moon, Ceres, and Io would qualify as planets. The video contrasts the IAU's prescriptive list (Mercury through Neptune) with a potentially more scientifically consistent classification based on physical properties, as illustrated by Margot's Planetary Discriminant chart.

Context: This video critiques the 2006 International Astronomical Union (IAU) definition of a planet, which controversially reclassified Pluto as a dwarf planet. The presenter breaks down the three criteria established by the IAU for an object to be considered a planet in our Solar System and then tests whether the Earth's Moon meets these criteria, concluding that it meets the first two but fails the third because it is a satellite, a condition explicitly excluded by the definition's footnotes.