Cosmology and Sailor Moon

Cosmology references in Sailor Moon

Welcome class, today we are going to be talking about Sailor Moon. Sailor Moon was the brain child of Naoko Takeuchi, and first hit the shelves back in 1992. It can be seen as the successor to the less well known Code Name Sailor V. Over the years it has been adapted into a live action TV show, musicals, and 2 different anime series. The show is famous for helping to create the modern magical girl warrior trope and set many of the conventions seen in magical girl shows over of the years. However, more importantly to the western fans, it was a gateway show that helped to bring anime to the west in the mid to late 1990s. While I myself did not see Sailor Moon until much later, and I am not much of a fan, it no doubt had a large impact on expanding anime’s reach beyond Japan.

Ok, Mr. Meharg, that is all well and good, but what does it have to do with science?

If you don’t already know, or haven’t figured it out from the name, Sailor Moon is littered with Cosmological references. FYI- Cosmology is the study of the nature and structure of the universe. Also, the reason for this post is that it was inspired by my class which just finished covering the solar system and most of them had no idea who or what Sailor Moon was.


Sailor Scouts

scouts are broken into two groups: the inner scouts and the outer scouts, which parallels how the planets are broken into two basic groups. The inner planets of the solar system are found inside the asteroid belt (Mercury, Venus, Earth, Mars) and the outer planets of the solar system (Jupiter, Saturn, Uranus, Neptune), are found beyond the asteroid belt.

Inner Scouts

Inner Sailor Scouts
Clockwise from the center- Sailor Mercury, Sailor Jupiter, Sailor Mars, Sailor Venus, Sailor Moon

Ami Mizuno aka Sailor Mercury is named after the first planet from the sun, Mercury. Mercury was the Roman god of messengers, finance, travelers, and several others. While she uses the Roman naming, her powers are inspired by Asian mythology.

Minako Aino aka Sailor Venus is named after the second planet from the sun and the Roman goddess of love. In one particular instance in Code Name Sailor V she uses an attack called Venus Sulphur Smoke to incapacitate someone, which is either the atmosphere of Venus, or her own flatulence. Assuming it is the atmosphere of Venus, then the attack would be far more dangerous than it is shown in the manga. At 467 degrees C, it would be much more likely to burn a person’s skin off. The gas would be 96.5% carbon dioxide, and 3.5% nitrogen, with a significant amount of sulfuric acid rain. Perfect for roasting demons; humans on the other hand, not so much. Sailor Venus also has a number of light based attacks, which make sense when you consider that Venus is the third brightest object in the sky after the Sun and Moon.

Usagi Tsukino aka Sailor Moon the former Princess Serenity. Her alter ego is named after the moon and Princess Serenity may have been inspired by Selene the Roman goddess of the moon. Her light based attacks make sense when you consider that the moon is the second brightest object in the night sky.

Chibiusa aka Sailor Mini moon is Usagi’s future daughter and shares her mother’s powers of the moon.

Rei Hino aka Sailor Mars is named after the fourth planet from the sun, which is named after the Roman god of war.

Makoto Kino aka Sailor Jupiter is named after the fifth planet from the sun which takes its name from the Roman king of the gods. Given this it is no surprise that she is the tallest and physically the strongest of all the Sailor Scouts.  One more thing to note is that Jupiter is technically an outer planet of the solar system as it is beyond the asteroid belt but Sailor Jupiter is included with the inner scouts.

Outer Scouts

The outer scouts represent the gas and ice giants of the outer solar system of which Sailor Jupiter is absent having been included in the inner scouts.

Outer Sailor Scouts
Top to bottom- Sailor Pluto, Sailor Neptune, Sailor Uranus, Sailor Saturn

Hotaru Tomoe aka Sailor Saturn is named after the sixth planet from the sun, and the father of Zeus in Greek mythology. Interestingly enough based on the Greco-Roman mythology references Saturn should control time and Pluto death, but they were switched for some reason.

Haruka Tenou aka Sailor Uranus is named after the seventh planet from the sun, and the Greek God of the sky.

Michiru Kaiou aka Sailor Neptune is named after the eight planet from the sun, which takes its name from the Roman god of the sea.

Setsuna Meiou aka Sailor Pluto was named after the planet Pluto, which draws its name from the Roman god of the underworld. As stated previously her powers were switched with Sailor Saturn. Now you notice earlier I said was a planet, because in 2006 the International Astronomical Union downgraded Pluto to a dwarf planet. This was done due to the discovery of another dwarf planet Eris formerly Xena in 2005 which is 27% larger than Pluto.

Pluto demoted
Darn you science
Ok so what is a dwarf planet?

1- is in direct orbit of the Sun
2- is massive enough for its gravity to turn it into a nearly round shape
3- has not cleared the neighborhood around its orbit, i.e., there are still asteroids, meteors, and other space debris in and around its orbit.
Currently there are five dwarf planets- Pluto, Ceres, Haumea, Makemake, and Eris.

Male characters

Mamoru Chiba aka Prince Endymion is named after a mythological Greek shepherd or king, who just so happens to have an asteroid and Lunar crater named after him.

Helios is an important character in a later season of Sailor Moon who is named after a Greek sun god. This is also the name of a main belt asteroid, French military satellites, and a French space probe.?

Advisers, also known as the moon cats

Moon Cats
Left to right- Artemis, Luna, Diana

Luna aka (Sailor Luna on special occasions) is Usagi’s talking pet cat, and advisor.  She is named after another Roman goddess of the moon, Luna.
Diana is Chibusa’s cat advisor named after the Roman goddess of the hunt.  Diana is also the name of a Lunar crater and a large main belt asteroid of the asteroid belt.
Minako also has a pet cat advisor Artemis, who is named after the Greek goddess of the hunt.  There is also a lunar crater named Artemis continuing the astronomical references.

Other animals

Rei just so happens to have two pet crows named Phobos, and Deimos after the pair of asteroids that the gravity of Mars pulled into orbit as moons.
Pegasus the winged horse is a main character in a later arc of the show and is also the name of a constellation.
Kirin was a baby plesiosaur that the Sailor Scouts rescued at one point and it just so happens to be the name of a meteorite that landed in northeastern China in 1976.


The Amazon Quartet were named after the largest asteroids in the asteroid belt.

Amazoness Quartet
Right to left Jun Jun, Cerecere, Vesves, Pallapala

Vesves, or Sailor Vesta is named after the minor planet Vesta and is the second largest object in the asteroid belt.  This is also shown in her character design where she is one of the tallest out of the group.
Cerecere or Sailor Ceres is named after the dwarf planet Ceres and is the largest object in the asteroid belt.  She also happens to be the tallest of the four.
Junjun or Sailor Juno is named after the 11th largest asteroid in the asteroid belt and it also is the name of a NASA space probe. The space probe came after the publication of Sailor Moon though.
Pallapalla or Sailor Palla is named after a large asteroid in the asteroid belt and a crater on the moon.
Queen Nehellenia, yes, I know that there is no celestial body named Nehellenia, but there is an astronomy reference. Queen Nehellenia is supposed to be the dark alter ego of Sailor Moon from the dark side of the moon. This has an astronomical reference as the orbital period (the time it takes for the moon to orbit the earth) is equal to the rotational period (the time it takes for the moon to rotate on its axis). This means that the side of the moon that we see from Earth (light side) is always facing Earth, and the side that we can’t see (dark side), is always facing away. Oh, and the light that she uses to break free comes from a Solar eclipse which would be the only time the dark side of the moon would be exposed to large amounts of light.
Regulus, this monster of the week is a stylized Lion named after the star Regulus, the brightest star in the Leo constellation, befitting his lion like form.


Sagitaruis Zero star or Galaxy Cauldron, which is the center of the Milky Way Galaxy in the Sailor Moon universe. It is also said to be the birthplace of stars. The center of the Milkly Way Galaxy is a real thing, and it does have large number of stars. Most of these stars are older red giants with only about a 100 or so very large very young (on a stellar scale) stars.  However at the center of everything there is a super massive black hole.

Sagitaruis Zero star
Center of the Milky way galaxy

This super massive black hole is part of what keeps the Milky Way together and causes the stars in the Galaxy to orbit the center. Thus it’s probably a good thing Sailor didn’t destroy it, as it would be very bad for the galaxy.

Nemesis is the home of the Black Moon clan. At the time Sailor Moon was written it was thought that there could be a hypothetical tenth planet of the solar system. This was proven to be true in 2003 with the discovery of another dwarf planet named UB313. However much more recently Caltech found evidence of a potentially larger celestial body orbiting far beyond Pluto’s orbit.

The Tau Nebula is the home of Pharoh 90.  While there is no Tau Nebula, Naoko Takeuchi could have been making a reference to either the T Tauri star in the Tarus constellation or the Tau Ceti star system in the Cetus constellation.  My money is on the Tau Ceti system as it actually contains a planet, which could serve as a home for Pharoh 90.
Well dang there turned out to be a bit more than I thought.  I hope everyone found this interesting at the very least and please leave any comments in the comment section below.

2 thoughts on “Cosmology and Sailor Moon

  1. Chris Meharg says:

    Sadly I do not know of any myself. I made a thread on spacebattles and animesuki that haven’t gotten any traction. I also made a google + group, but again it hasn’t taken off as I am new to this stuff.

    So I guess it is up to us to make one. I’ve done this at anime conventions and had good turnouts so I think the interest is there its just finding people.

  2. Pingback: Anime Science 101- Anime Physics- Time Travel as seen in anime

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