3063: Planet Definitions

Explanation

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This comic addresses the controversy of whether of Pluto is a planet and gives many other humorous definitions, most of them fairly nonsensical, of what a planet could be.

Traditionalist: Pluto is a planet (9 planets)

In modern times, there was no formal definition of a "planet" prior to 2006. However, it was generally accepted as a colloquialism there were nine planets around the Sun, Pluto included. As more sophisticated methods of mapping the Solar System were developed and Eris was discovered to be even more massive than Pluto, it became clear to astronomers that a more standardized definition was needed. In 2006 the International Astronomical Union (IAU) published their formal redefinition of a "planet" to require a planet to be gravitationally dominant within its orbit, disqualifying Pluto (and Eris) which is now considered a "dwarf planet." This has been subject to push back from countless people, including some planetary scientists, but in numbers mostly nostalgic laypeople dissatisfied with Pluto being "demoted" or otherwise relegated.

Modern: Pluto is not a planet (8 planets)

When the IAU redefined what a planet is in 2006, Pluto no longer qualifies as a planet. (since it wasn't able to clear its neighborhood around its orbit) Using the modern definition of a planet, only eight celestial objects qualified.

Expansive: Dwarf planets are planets (17+ planets)

It is likely that since the term "dwarf planet" contained "planet" in its name, Randall considered those as also planets under this category.

It is also likely that the number of planets includes the ones that are considered planets and the ones that are considered to have compacted into fully solid bodies, as defined by Grundy et al.,,^{[actual citation needed]} those being Ceres, Pluto, Eris, Makemake, Gonggong, Quaoar, Orcus, and Sedna. [[1]]

Ultratraditionalist: Only the classical planets are planets (5 planets)

The classical planets are objects found and considered by the Greek astronomers in classical antiquity to be considered planets. Their definition of "planet" considered visible objects that move across the sky relative to the fixed stars. There are seven classical planets, but if one were to only consider the ones that fall under the IAU's definition of a planet (This being less traditional), then there would only be five. (The Sun and the Moon would be disqualified)

Condescending: Only giant planets are planets; the rest are big asteroids (4 planets)

This definition may refer to the giant planets, planets much larger than Earth. Only the four outer planets fall under this definition.

Simplistic: Anything gravitationally round is a planet (37+ planets)

Using the Wikipedia list of gravitationally rounded objects of the Solar System, there are 37 objects listed. That includes the Sun, 7 planets, 10 dwarf planets, and 19 moons.

Grounded: Only objects a spaceship has landed on are planets (10 planets)

This list includes objects in the Solar System that a spacecraft has performed a soft landing on. The list include Venus, Earth, Mars, the Moon, Titan, Eros, Itokawa, Ryugu, and Bennu. Notably, comet landings are not included in the list.

Regolithic: Anything covered in dirt and ice and stuff is a planet (infinite)

This list excludes the Gas Giants and the Ice Giants. The list would likely include dwarf planets, asteroids, moons, and comets.

Lunar: You can't be a planet if you don't have a moon (12+ objects)

Only some objects in the Solar System contains captured moons. The value given may be the number of planets and consensus dwarf planets that contain moons when excluding Haumea for not reaching hydrostatic equilibrium despite having moons.

Solipsistic: Earth is the only planet (1 planet)

Solipsism is the idea that only one's own mind is sure to exist. Randall extrapolated this idea to mean that only one's own planet that they are standing on is sure to exist.

Judgemental: Only the prettiest ones are planets (6 planets)

This list is likely formulated from Randall's own perception of the prettiest planets in the Solar System. There is a common misconception that Neptune has a deep, dark blue color while in reality it is similar to Uranus's pale, greenish-blue color, making it look less pretty.

Empiricist: Only worlds that I, author of this table, have personally seen are planets (12 planets)

This list may refer to the celestial objects in the Solar System that are visible at night with the naked eye. Jupiter's four largest moons are technically visible but hard to distinguish due to Jupiter's brightness, while Neptune is too faint to see with a naked eye. Apparently Randall has seen Uranus (see 'Empiricist'). This is fairly rare, since it usually requires a telescope pointed in just the right direction. Technically Uranus is visible to the naked eye under the very best viewing conditions, but these conditions are rare and it again requires knowing exactly where to look.

Marine biologist: Only objects with oceans are planets (6+ planets)

This list includes Earth, Europa, Ganymede, Callisto, Europa, and Enceladus.

Maritime: Only objects with surface oceans are planets (2 planets)

As of the time of posting of this comic, only Earth has been proven to have a surface ocean. However, other objects in the Solar System could have a surface ocean, those being Enceladus and Europa; it is unclear which Saturnian moon falls into this category as Europa (a Jovian moon) is excluded despite having cryogeysers similar to Enceladus.

Universalist: They're all planets (infinite)

This list claims that all objects are planets.

Existantialist: What if space itself is a planet??? (Duude)

This list is different from the list above as it claims that all of space, rather than only the objects existing in space, are planets.

Spiteful: Only Pluto is a planet (1 planet)

This list is a malicious play on the demotion of Pluto by demoting all other planets except Pluto instead, leaving Pluto as the only planet in the Solar System.

(title text) Star: Earth is a star (2 stars)

In May 1934, Mark Oliphant, Paul Harteck, and Ernest Rutherford at the Cavendish Laboratory, published an intentional deuterium fusion experiment, and made the discovery of both tritium and helium-3. This is widely considered the first experimental demonstration of fusion. Randall considers that this makes Earth fall into the category of a star due to the human-induced ability for Earth to fuse hydrogen into helium using nuclear fusion.