Planetary mnemonic

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A representation of the above method with the left hand representing the terrestrial planets and the right hand, with palm turned upward, is representing the gas giants along with TNOs Solar System Hand Mnemonic.png
A representation of the above method with the left hand representing the terrestrial planets and the right hand, with palm turned upward, is representing the gas giants along with TNOs

A planetary mnemonic refers to a phrase created to remember the planets and dwarf planets of the Solar System, with the order of words corresponding to increasing sidereal periods of the bodies. One simple visual mnemonic is to hold out both hands side-by-side with thumbs in the same direction (typically left-hand facing palm down, and right-hand palm up). The fingers of hand with palm down represent the terrestrial planets where the left pinkie represents Mercury and its thumb represents the asteroid belt, including Ceres. The other hand represents the gas giants, with its thumb representing trans-Neptunian objects, including Pluto.

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Nine planets

An English-language mnemonic which was current in the 1950s was "Men Very Easily Make Jugs Serve Useful Needs, Perhaps" (for Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto). The structure of this sentence suggests that it may have originated before Pluto's discovery, and can easily be trimmed back to reflect Pluto's demotion to dwarf planet. Another common English-language mnemonic for many years was "My Very Educated (or Eager) Mother Just Served Us Nine Potatoes (or Pizzas)". Other mnemonics include "My Very Elegant Mother Just Sat Upon Nine Porcupines", [1] "My Very Energetic Mother Jumps Skateboards Under Nana's Patio" and "Mary's violet eyes make Johnnie stay up nights pondering", [2] as well as the apt "My Very Easy Method Just Shows Us Nine Planets", "My Very Efficient Memory Just Stores Up Nine Planets" and "My Very Easy Method Just Speeds Up Naming Planets [3] ".

Many of these mnemonics were made obsolete in 2006, however, with the IAU's 2006 definition of planet which reclassified Pluto as a dwarf planet, along with Ceres and Eris.

Eight planets

When Pluto's significance was changed to dwarf planet, mnemonics could no longer include the final "P". The first notable suggestion came from Kyle Sullivan of Lumberton, Mississippi, USA, whose mnemonic was published in the Jan. 2007 issue of Astronomy magazine: "My Violent Evil Monster Just Scared Us Nuts". [4] In August 2006, for the eight planets recognized under the new definition, [5] Phyllis Lugger, professor of astronomy at Indiana University suggested the following modification to the common mnemonic for the nine planets: "My Very Educated Mother Just Served Us Nachos". She proposed this mnemonic to Owen Gingerich, Chair of the International Astronomical Union (IAU) Planet Definition Committee and published the mnemonic in the American Astronomical Society Committee on the Status of Women in Astronomy Bulletin Board on August 25, 2006. [6] It also appeared in Indiana University's IU News Room Star Trak on August 30, 2006. [7] This mnemonic is used by the IAU on their website for the public. [8]

Others angry at the IAU's decision to "demote" Pluto composed sarcastic mnemonics in protest. Schott's Miscellany by Ben Schott included the mnemonic, "Many Very Educated Men Justify Stealing Unique Ninth". [9] Mike Brown, who discovered Eris, mentioned hearing "Many Very Educated Men Just Screwed Up Nature". [10] One particular 9 planet mnemonic, "My very easy memory jingle seems useful naming planets", was easily changed once the demotion occurred, becoming the 8 planet mnemonic, "My very easy memory jingle seems useless now". Another mnemonic which was changed from 9 to 8 planets was , "Most Very Elderly Men Just Slept Under Newspapers".[ citation needed ] Slightly risque versions include, "Mary's 'Virgin' Explanation Made Joseph Suspect Upstairs Neighbor". [11]

Eleven planets and dwarf planets

In 2007, the National Geographic Society sponsored a contest for a new mnemonic of MVEMCJSUNPE, incorporating the then-eleven known planets and dwarf planets, including Eris, Ceres, and the newly demoted Pluto. On February 22, 2008, "My Very Exciting Magic Carpet Just Sailed Under Nine Palace Elephants", coined by 10-year-old Maryn Smith of Great Falls, Montana, was announced as the winner. [12] The phrase was featured in the song 11 Planets by Grammy-nominated singer and songwriter Lisa Loeb and in the book 11 Planets: A New View of the Solar System by David Aguilar ( ISBN   978-1426302367). [13]

Thirteen planets and dwarf planets

Since the National Geographic competition, two additional bodies were designated as dwarf planets, Makemake and Haumea, on July 11 and September 17, 2008 respectively. A 2015 New York Times article suggested some mnemonics including, "My Very Educated Mother Cannot Just Serve Us Nine Pizzas—Hundreds May Eat!" [14]

Longer mnemonics will be required in the future, if more of the possible dwarf planets are recognized as such by the IAU. However, at some point enthusiasm for new mnemonics will wane as the number of dwarf planets exceeds the number that people will want to learn (it is estimated that there may be up to 200 dwarf planets [15] ).

See also

Related Research Articles

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In astronomy, a double planet is a binary satellite system where both objects are planets, or planetary-mass objects, that share an orbital axis external to both planetary bodies.

<span class="mw-page-title-main">Planet</span> Large, round non-stellar astronomical object

A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a young protostar orbited by a protoplanetary disk. Planets grow in this disk by the gradual accumulation of material driven by gravity, a process called accretion. The Solar System has at least eight planets: the terrestrial planets Mercury, Venus, Earth, and Mars, and the giant planets Jupiter, Saturn, Uranus, and Neptune. These planets each rotate around an axis tilted with respect to its orbital pole. All the major planets of the Solar System other than Mercury possess a considerable atmosphere, and some share such features as ice caps, seasons, volcanism, hurricanes, tectonics, and even hydrology. Apart from Venus and Mars, the Solar System planets generate magnetic fields, and all the major planets except Venus and Mercury have natural satellites. The giant planets bear planetary rings, the most prominent being those of Saturn.

<span class="mw-page-title-main">Planets beyond Neptune</span> Hypothetical planets further than Neptune

Following the discovery of the planet Neptune in 1846, there was considerable speculation that another planet might exist beyond its orbit. The search began in the mid-19th century and continued at the start of the 20th with Percival Lowell's quest for Planet X. Lowell proposed the Planet X hypothesis to explain apparent discrepancies in the orbits of the giant planets, particularly Uranus and Neptune, speculating that the gravity of a large unseen ninth planet could have perturbed Uranus enough to account for the irregularities.

<span class="mw-page-title-main">Pluto</span> Dwarf planet

Pluto is a dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Sun. It is the largest known trans-Neptunian object by volume, by a small margin, but is slightly less massive than Eris. Like other Kuiper belt objects, Pluto is made primarily of ice and rock and is much smaller than the inner planets. Pluto has only one sixth the mass of Earth's moon, and one third its volume. Pluto was recognized as a planet until 2006.

<span class="mw-page-title-main">90482 Orcus</span> Trans-Neptunian object and dwarf planet

Orcus is a large trans-Neptunian planetoid with a large moon, Vanth. It has a diameter of 870 to 960 km, the size of or somewhat smaller than the Inner Solar System dwarf planet Ceres. Orcus is generally accepted by astronomers as a dwarf planet, although there is some doubt. The surface of Orcus is relatively bright with albedo reaching 23 percent, neutral in color and rich in water ice. The ice is predominantly in crystalline form, which may be related to past cryovolcanic activity. Other compounds like methane or ammonia may also be present on its surface. Orcus was discovered by American astronomers Michael Brown, Chad Trujillo, and David Rabinowitz on 17 February 2004.

<span class="mw-page-title-main">90377 Sedna</span> Dwarf planet

Sedna is a dwarf planet in the outermost reaches of the Solar System discovered in 2003. Spectroscopy has revealed that Sedna's surface composition is largely a mixture of water, methane, and nitrogen ices with tholins, similar to those of some other trans-Neptunian objects. Its surface is one of the reddest among Solar System objects. Sedna, within estimated uncertainties, is tied with Ceres as the largest planetoid not known to have a moon. It has a diameter of approximately 1,000 km ; its mass is unknown.

<span class="mw-page-title-main">Michael E. Brown</span> American astronomer (born 1965)

Michael E. Brown is an American astronomer, who has been professor of planetary astronomy at the California Institute of Technology (Caltech) since 2003. His team has discovered many trans-Neptunian objects (TNOs), including the dwarf planet Eris, which was originally thought to be bigger than Pluto, triggering a debate on the definition of a planet.

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Mesoplanets are planetary-mass objects with sizes smaller than Mercury but larger than Ceres. The term was coined by Isaac Asimov. Assuming size is defined in relation to equatorial radius, mesoplanets should be approximately 500 km to 2,500 km in radius.

<span class="mw-page-title-main">Dwarf planet</span> Small planetary-mass object

A dwarf planet is a small planetary-mass object that is in direct orbit of the Sun, smaller than any of the eight classical planets. The prototypical dwarf planet is Pluto. The interest of dwarf planets to planetary geologists is that they may be geologically active bodies, an expectation that was borne out in 2015 by the Dawn mission to Ceres and the New Horizons mission to Pluto.

IAU definition of <i>planet</i> 2006 International Astronomical Union definition

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  1. is in orbit around the Sun,
  2. has sufficient mass to assume hydrostatic equilibrium, and
  3. has "cleared the neighbourhood" around its orbit.
<span class="mw-page-title-main">Eris (dwarf planet)</span> Dwarf planet beyond Pluto in the Solar System

Eris is the most massive and second-largest known dwarf planet in the Solar System. It is a trans-Neptunian object (TNO) in the scattered disk and has a high-eccentricity orbit. Eris was discovered in January 2005 by a Palomar Observatory–based team led by Mike Brown and verified later that year. In September 2006, it was named after the Greco–Roman goddess of strife and discord. Eris is the ninth-most massive known object orbiting the Sun and the sixteenth-most massive overall in the Solar System. It is also the largest known object in the solar system that has not been visited by a spacecraft. Eris has been measured at 2,326 ± 12 kilometers (1,445 ± 7 mi) in diameter; its mass is 0.28% that of the Earth and 27% greater than that of Pluto, although Pluto is slightly larger by volume. Both Eris and Pluto have a surface area that is comparable to the area of Russia or South America.

<span class="mw-page-title-main">Small Solar System body</span> Object in the Solar System

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In astronomy, planetary mass is a measure of the mass of a planet-like astronomical object. Within the Solar System, planets are usually measured in the astronomical system of units, where the unit of mass is the solar mass (M), the mass of the Sun. In the study of extrasolar planets, the unit of measure is typically the mass of Jupiter (MJ) for large gas giant planets, and the mass of Earth (MEarth) for smaller rocky terrestrial planets.

<span class="mw-page-title-main">Gonzalo Tancredi</span> Uruguayan astronomer (born 1963)

Gonzalo Tancredi is an Uruguayan astronomer and full professor in the Department of Astronomy at the University of the Republic in Montevideo, Uruguay. He is an active member of the International Astronomical Union (IAU) and investigator at Los Molinos Observatory.

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References

  1. "My Very Elegant Mother Just Sat Upon Nine Porcupines". www.rocemabra.com. Retrieved 2019-10-10.
  2. Beatty, Kelly (2008-02-28). "Of Planets and Palace Elephants". SkyandTelescope.com. Archived from the original on 2013-02-02. Retrieved 2008-09-16.
  3. Garfoot, Ash (May 2000). "Ash Garfoot (May 2000)". www.facebook.com. Retrieved 2020-09-25.
  4. "Physics 110 Astronomy Mnemonics". www.csub.edu/Physics. Archived from the original on 2012-01-18.
  5. "International Astronomical Union, iau0603 -- Press Release, IAU 2006 General Assembly: Result of the IAU Resolution votes, 24 August 2006" . Retrieved 2016-01-30.
  6. "American Astronomical Society Committee on the Status of Women in Astronomy Bulletin Board, August 25, 2006". Archived from the original on 2016-05-07. Retrieved 2016-01-30.
  7. "Indiana University, IU News Room, Star Trak, August 30, 2006" . Retrieved 2016-01-30.
  8. "Pluto and the Developing Landscape of Our Solar System, Questions and Answers". International Astronomical Union, IAU for the Public. Retrieved 2016-01-30.
  9. Schott, Ben (2008). Schott's Miscellany 2009. New York: Bloomsbury USA. p. 77. ISBN   978-1-59691-382-0.
  10. "Julia Sweeney and Michael E. Brown". Armand Hammer. 2007. Archived from the original on 2008-10-06. Retrieved 2009-12-14.
  11. "XKCD Presents: Some New Science Mnemonics".
  12. "National Geographic Children's Books Announces Winner of New Planetary Mnemonic". Archived from the original on March 6, 2008. Retrieved 2008-02-29.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  13. "Planet Song". National Geographic. Archived from the original on February 24, 2012. Retrieved September 23, 2008.
  14. "My Very Educated Readers, Please Write Us a New Planet Mnemonic". The New York Times. January 20, 2015. Retrieved June 20, 2015.
  15. "Our Solar System has 127 probable planets and 500+ possibles | NextBigFuture.com". 2018-09-08. Retrieved 2023-02-15.