The planetary mnemonic refers to the phrase used to remember planets and dwarf planets of the Solar System, with the order of words corresponding to the growing periodic bodies of celestial bodies. One simple visual mnemonic consists of holding both hands next to each other with spread fingers and thumbs in the same direction, with fingers of one hand depicting Earth’s planets, and on the other hand with gas giants. The first thumb represents the Sun and the asteroid belt, including Ceres, and the second thumb represents the asteroid belt and trans-Neptune objects, including Pluto.
The English-language mnemonic that was present in the 1950s was: “Men very easily make jugs, serving their needs, perhaps” (for Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto). The structure of this sentence suggests that it could have been created before the discovery of Pluto and could easily be withdrawn to reflect the degradation of Pluto. Another popular English memory for many years was “My very elegant mother just sat on nine pins”. Other mnemonics are “My very energetic mothers are jumping on skateboards under Nana’s patio,” and Mary’s “purple eyes make Johnnie spend her night in meditation”, and the apt “My very easy method shows us only nine planets”, “My Very efficient memory allows only to remember nine planets “and” my very easy method only speeds up coming up with the planet
. Another option that may precede the discovery of Pluto is “Mary’s purple eyes make Johnny spend the night wondering” and this can also be cut back. Still, another is “Many volcanoes emulate sandwiches with plentiful jam under normal pressure.” However, many of these mnemonics have become outdated thanks to the 2006 definition of the planet, which has reclassified Pluto (in the same way as Ceres and Eris) as a dwarf planet.
When Pluto was demoted to the dwarf planet, the mnemonics could no longer contain the final “P”. The first notable suggestion comes from Kyle Sullivan of Lumberton, Mississippi, USA, whose mnemonic was published in the Astronomy magazine from January 2007: “My Violent Evil Monster Just Scared Us Nuts.” In August 2006, in the case of the eight planets recognized in the new definition, Phyllis Lugger, professor of astronomy at the University of Indiana, suggested the following modification of the universal mnemonics for nine planets: “My very educated mother just served us Nachos.” She proposed this mnemonic to Owen Gingerich, chair of the Planetary Planning Definition Commission of the International Astronomical Union (IAU), and published a list of mnemonics at the American Society of Astronomical Society for the Status of Women in the Astronomical Information Bulletin August 25, 2006. He also appeared in the IU News Room Star Trak at Indiana University on August 30, 2006. This mnemonic is used by the IAU on their website to the public. Others angry at the IAU’s decision to “demote” Pluto composed sarcastic mnemonics in protest. In “Miscellany Schott” Ben Schott included a mnemonic, “Many Very Educated Men Justify Stealing Unique Ninth”. Mike Brown, who discovered Eris, mentioned the interrogation of “Many very educated people just bound by nature”. One of the 9 mnemonics of the planet, “My very simple memory seems to be useful naming the planets,” it easily changed after being degraded, becoming 8 mnemonic planets, “My very simple memory now seems useless.” A somewhat risque version is “Mary” Virgin ‘Explanation Made by Joseph Suspect Upstairs Neighbor.  Or perhaps the simplest of all: “My very easy method: just an ELEPHANT.”
Eleven planets and dwarf planets
In 2007, the National Geographic Society sponsored a competition for the new MVEMCJSUNPE mnemonic, containing 11 known planets and dwarf planets, including Eris, Ceres, and the newly degraded Pluto. February 22, 2008, The winner of “My Very Exciting Magic Carpet Just Sailed Under Nine Palace Elephants” was announced, coined by 10-year-old Maryn Smith from Great Falls, Montana. This phrase was in the song 11 Planets nominated for the Grammy award, singer and songwriter Lisa Loeb and in the book 11 Planets: New View of the Solar System by David Aguilar (ISBN 978-1426302367).
Thirteen planets and dwarf planets
Since the National Geographic competition, two additional bodies have been identified as dwarf planets, Makemake and Haumea, on July 11 and September 17, 2008, respectively. The New York Times article from 2015 suggested some mnemonics, including: “My very educated mother cannot just serve us nine pizzas – hundreds can eat!”
Longer mnemonics will be required in the future if a larger number of possible dwarf planets will be considered by the IAU as such. However, at some point, the enthusiasm for new mnemonics will decrease when the number of dwarf planets exceeds the number that people will want to learn. (It is estimated that there may be 200 dwarf planets.)