A planet symbol (or planetary symbol) is a graphical symbol either in astrology or astronomy representing either a classical planet (including the Sun and the Moon) or one of the eight modern planets. In alchemy, the symbols are also used to represent the metals which are associated with the respective planets.
The use of these symbols is based in ancient Greco-Roman tradition, although their current shapes are a development of the 16th century. The classical planets with their symbols and associated metals are:
For the purposes of modern astronomy, the International Astronomical Union discourages the use of these symbols in journal articles. In certain cases where planetary symbols might be used, such as in the headings of tables, the IAU Style Manual propose one- and (to disambiguate Mercury and Mars) two-letter abbreviations for the names of the planets. The modern planets with their symbols an abbreviations recommended by the IAU are:
The symbols of Venus and Mars are also used to represent female and male in biology and botany, following a convention introduced by Linnaeus in the 1750s, and by extension they have also come into use as "gender symbols" in the second half of the 20th century.
The written symbols for Mercury, Venus, Jupiter, and Saturn have been traced to forms found in late Greek papyri. Early forms are also found in medieval Byzantine codices in which many ancient horoscopes were preserved. Antecedents of the planetary symbols are attested in the form of attributes given to the respective classical deities, represented in simplified pictographic form already in the Roman era, as attested in the Bianchini's planisphere (2nd century, Louvre inv. Ma 540) where the seven planets are represented by portraits of the seven corresponding gods, each with a simple representation of an attribute, as follows: Mercury has a caduceus; Venus has, attached to her necklace, a cord connected to another necklace; Mars, a spear; Jupiter, a staff; Saturn, a scythe; the Sun, a circlet with rays emanating from it; and the Moon, a headdress with a crescent attached.
A diagram in the astronomical compendium by Johannes Kamateros (12th century) shows the Sun represented by the circle with a ray, Jupiter by the letter zeta (the initial of Zeus, Jupiter's counterpart in Greek mythology), Mars by a shield crossed by a spear, and the remaining classical planets by symbols resembling the modern ones, without the cross-mark seen in modern versions of the symbols. These cross-marks first appear in the late 15th or early 16th century. According to Maunder, the addition of crosses appears to be "an attempt to give a savour of Christianity to the symbols of the old pagan gods."
The modern symbols for the seven classical planets (with an additional crossbar in the symbol for Mercury) are found in a woodcut of the seven planets, represented as the corresponding gods riding chariots, in a Latin translation of Abu Ma'shar's De Magnis Coniunctionibus printed at Venice in 1506.
- Early modern depiction of the planet symbols in an alchemical context (Musaeum Hermeticum, 1678)
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Earth is not, of course, one of the classical planets. Its status as planet is a consequence of the development of heliocentrism. Nevertheless, there are ancient symbols for Earth, notably a cross representing the four cardinal directions, as a cross in a circle also interpreted as a globe with equator and a meridian; The "Earth" symbol is encoded by Unicode at U+1F728 (🜨; alternative characters with similar shape are: U+2295 ⊕ CIRCLED PLUS; U+2A01 ⨁ N-ARY CIRCLED PLUS OPERATOR). Alternatively, there is the globus cruciger (U+2641 ♁), now most commonly used as planetary symbol. The "globus cruciger" symbol is also used as an alchemical symbol of antimony.
Uranus (U+26E2 ⛢, also U+2645 ♅, a globe surmounted by the letter H for Herschel): The symbols for Uranus were created shortly after its discovery in 1781. One symbol, , invented by J. G. Köhler and refined by Bode, was intended to represent the newly discovered metal platinum; since platinum, commonly called white gold, was found by chemists mixed with iron, the symbol for platinum combines the alchemical symbols for iron, ♂, and gold, ☉. This symbol also combines the symbols of Mars (♂) and the Sun (☉) because in Greek Mythology, Uranus represented heaven, and represents the combined power of Mars' spear and the Sun. Another symbol, , was suggested by Lalande in 1784. In a letter to Herschel, Lalande described it as "un globe surmonté par la première lettre de votre nom" ("a globe surmounted by the first letter of your name").
Neptune (U+2646 ♆, Neptune's trident, also , a globe surmounted by the letters "L" and "V" for Le Verrier): Several symbols were proposed for Neptune to accompany the suggested names for the planet. Claiming the right to name his discovery, Urbain Le Verrier originally proposed the name Neptune and the symbol of a trident, while falsely stating that this had been officially approved by the French Bureau des Longitudes. In October, he sought to name the planet Leverrier, after himself, and he had loyal support in this from the observatory director, François Arago, who in turn proposed a new symbol for the planet (). However, this suggestion met with stiff resistance outside France. French almanacs quickly reintroduced the name Herschel for Uranus, after that planet's discoverer Sir William Herschel, and Leverrier for the new planet. Professor James Pillans of the University of Edinburgh defended the name Janus for the new planet, and proposed a key for its symbol. Meanwhile, Struve presented the name Neptune on December 29, 1846, to the Saint Petersburg Academy of Sciences. In August 1847, the Bureau des Longitudes announced its decision to follow prevailing astronomical practice and adopt the choice of Neptune, with Arago refraining from participating in this decision.
Pluto was also considered a planet from its discovery in 1930 until its re-classification as a "dwarf planet" in 2007. The symbol used for Pluto was a ligature of the letters P and L (Unicode U+2647 ♇).
In the 19th century, symbols for the major asteroids were also in use, including Vesta (an altar with fire on it; ⚶ U+26B6), Juno (a sceptre; ⚵ U+26B5), Ceres (a reaper's scythe; ⚳ U+26B3), Pallas (⚴ U+26B4); Encke (1850) has further symbols for Astraea, Hebe, Iris, Flora and Metis. Unicode furthermore has a symbol for 2060 Chiron (discovered 1977), ⚷ U+26B7.
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The crescent shape has been used to represent the Moon since earliest times. In classical anqituity, it is worn by lunar deities (Selene/Luna, Artemis/Dianad, Men, etc.) either on the head or behind the shoulders, with its horns pointing upward. Its representation with the horns pointing sideways (as a heraldic crescent increscent or crescent decrescent) is early modern.
The same symbol can be used in a different context not for the Moon itself but for a lunar phase, as part of a sequence of four symbols for "new moon" (U+1F311 🌑), "waxing" (U+263D ☽), "full moon" (U+1F315 🌕) and "waning" (U+263E ☾).
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The symbol for Mercury (U+263F ☿ is ultimately derived from the caduceus, or intertwined serpents, which were the main attribute of Mercury/Hermes throughout antiquity. The caduceus was usually shown with at least three loops, but this was simplified to a single loop in the diagram of Kamateros (12th century). The modern symbol has also been interpreted as representing the god's winged headdress.
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The Venus symbol (♀) consists of a circle with a small cross below it. It originates in Late Antiquity as an astrological symbol for the planet Venus (associated with the goddess Venus), and hence as alchemical symbol for copper. In modern times, it is still used as the astronomical symbol for Venus, although its use is discouraged by the International Astronomical Union.
In zoology and botany, it is used to represent the female sex (alongside the astrological symbol for Mars representing the male sex), following a convention introduced by Linnaeus in the 1750s. Following the biological convention, the symbol in the 20th century also came to be used in sociological contexts to represent women or femininity.
The symbol appears without the cross-mark (⚲) in Johannes Kamateros (12th century). In the Bianchini's planisphere (2nd century), Venus is represented by a necklace. The idea that the symbol represents the goddess' hand mirror dates to the 19th century.
- Medieval (Johannes Kamateros, 12th century) form of the Venus symbol; the horizontal stroke was added to form a Christian cross in the early modern period.
- The Venus symbol in the municipal coat of arms of Falun Municipality in Sweden (1932), here representing copper mining.
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The modern astronomical symbol for the Sun (circled dot, Unicode U+2609 ☉) was first used in the Renaissance.
Bianchini's planisphere, produced in the 2nd century, has a circlet with rays radiating from it. A diagram in Johannes Kamateros' 12th century Compendium of Astrology shows the Sun represented by a circle with a ray. This older symbol is encoded by Unicode (version 9.0, June 2016) as "ALCHEMICAL SYMBOL FOR GOLD" at U+1F71A (🜚) in the Alchemical Symbols block.
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The Mars symbol (♂) is a depiction of a circle with an arrow emerging from it, pointing at an angle to the upper right. As astrological symbol it represents the planet Mars (connected to the god Mars (Ares)) and hence iron in alchemy. In zoology and botany, it is used to represent the male sex (alongside the astrological symbol for Venus representing the female sex), following a convention introduced by Linnaeus in the 1750s. It is encoded by Unicode as "MALE SIGN" at U+2642 in the Miscellaneous Symbols block
The symbol in its current form, representing spear and shield, dates to the early 16th century. It is derived from a medieval form where the spear was drawn across the shield, which in turn was based on a convention used in antiquity (Bianchini's planisphere) which represented Mars a spear. A diagram in the 12th-century Compendium of Astrology by Johannes Kamateros represents Mars by a shield crossed by a spear.
The symbol for iron, it also forms part of the logo of Volvo automobiles.
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The origin of the symbol for Jupiter (U+2643 ♃ is not entirely clear. Jupiter's attribute is a sceptre (as king of the gods), but Kamateros (12th century) represents Jupiter simply by the letter zeta ζ (for Zeus). The modern symbol as used from the 16th century is apparently based on a majuscule zeta Ζ with the addition of a vertical stroke to form the Christian cross. The less-than-intuitive symbol gave rise to various ad hoc interpretations by modern commentators; thus, the editors of the Penny cyclopedia (1842) thought might "supposed to be a symbol of the thunder (arm and hand holding thunder?)" and more recently the sign has been reported as based on the "Egyptian hieroglyph for the eagle".
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Saturn is usually depicted with a scythe or sickle, and the planetary symbol has apparently evloved from a picture of this attribute, in Kamateros (12th century) shown in a shape similar to the letter eta η, with the horizontal stroke added along with the "Christianization" of the other symbols in the early 16th century, (U+2644 ♄.
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- The IAU Style Manual (PDF). 1989. p. 27.
- Jones, Alexander (1999). Astronomical papyri from Oxyrhynchus. pp. 62–63. ISBN 0-87169-233-3.
- Neugebauer, Otto (1975). A history of ancient mathematical astronomy. pp. 788–789. ISBN 0-387-06995-X.
- "Bianchini's planisphere". Florence, Italy: Istituto e Museo di Storia della Scienza (Institute and Museum of the History of Science). Retrieved 2010-03-17.
- Maunder (1934)
- Maunder (1934:239)
- BNF Arabe 2583 fol. 15v. Saturn is shown as a black bearded man, kneeling and holding a scythe or axe; Mercury is shown as a scribe holding an open codex; Jupiter as a man of the law wearing a turban; Venus as a lute-player; Mars as a helmeted warrior holding a sword and the head of an enemy.
- The Penny cyclopædia of the Society for the Diffusion of Useful Knowledge. 22. C. Knight. 1842. p. 197.
- The Encyclopedia Americana: a library of universal knowledge. 26. Encyclopedia Americana Corp. 1920. pp. 162–163. Retrieved 2011-03-24.
- Johann Franz Encke, Berliner Astronomisches Jahrbuch für 1853, Berlin 1850, p. VIII
- Bode, J. E. (1784). Von dem neu entdeckten Planeten. pp. 95–96.
- Gould, B. A. (1850). Report on the history of the discovery of Neptune. Smithsonian Institution. p. 5.
- Cain, Fraser. "Symbol for Uranus". Universe Today. Retrieved 18 March 2013.
- Francisca Herschel (August 1917). "The meaning of the symbol H+o for the planet Uranus". The Observatory. Bibcode:1917Obs....40..306H.
- Schumacher, H. C. (1846). "Name des Neuen Planeten". Astronomische Nachrichten. 25: 81–82. Bibcode:1846AN.....25...81L. doi:10.1002/asna.18470250603.
- Littmann, Mark; Standish, E. M. (2004). Planets Beyond: Discovering the Outer Solar System. Courier Dover Publications. p. 50. ISBN 0-486-43602-0.
- Pillans, James (1847). "Ueber den Namen des neuen Planeten". Astronomische Nachrichten. 25 (26): 389–392. Bibcode:1847AN.....25..389.. doi:10.1002/asna.18470252602.
- Baum, Richard; Sheehan, William (2003). In Search of Planet Vulcan: The Ghost in Newton's Clockwork Universe. Basic Books. pp. 109–110. ISBN 0-7382-0889-2.
- Gingerich, Owen (1958). "The Naming of Uranus and Neptune". Astronomical Society of the Pacific Leaflets. 8: 9–15. Bibcode:1958ASPL....8....9G.
- Hind, J. R. (1847). "Second report of proceedings in the Cambridge Observatory relating to the new Planet (Neptune)". Astronomische Nachrichten. 25 (21): 309–314. Bibcode:1847AN.....25..309.. doi:10.1002/asna.18470252102.
- Bureau Des Longitudes, France (1847). Connaissance des temps: ou des mouvementes célestes, à l'usage des astronomes. p. unnumbered front matter.
- Cox, Arthur (2001). Allen's astrophysical quantities. Springer. p. 2. ISBN 0-387-95189-X.
- Mattison, Hiram (1872). High-School Astronomy. Sheldon & Co. pp. 32–36.
- "staff and winged helmet of Mercury" Tim Collins, Behind the Lost Symbol (2010), p. 128
- Stearn, William T. (May 1962). "The Origin of the Male and Female Symbols of Biology". Taxon. 11 (4): 109–113. doi:10.2307/1217734. JSTOR 1217734. "In his Systema Naturae (Leyden, 1735) he [Linnaeus] used them with their traditional associations for metals. Their first biological use is in the Linnaean dissertation Plantae hybridae xxx sistit J. J. Haartman (1751) where in discussing hybrid plants Linnaeus denoted the supposed female parent species by the sign ♀, the male parent by the sign ♂, the hybrid by ☿ 'matrem signo ♀, patrem ♂ & plantam hybridam ☿ designavero'. In subsequent publications he retained the signs ♀ and ♂ for male and female individuals but discarded ☿ for hybrids; the last are now indicated by the multiplication sign ×. Linnaeus's first general use of the signs of ♀ and ♂ was in his Species Plantarum (1753) written between 1746 and 1752 and surveying concisely the whole plant kingdom as then known." (p. 110)
- see Hiram Mattison, A high-school astronomy (1857), p. 32.
- In the official code chart glossed " = Venus = alchemical symbol for copper → 1F469 👩 woman → 1F6BA 🚺 womens symbol".
- Maunder (1934), p. 245.
- Falun was the site of a copper mine from at least the 13th century. A coat of arms including a copper sign is recorded for 1642; the current design dates to the early 20th century, and was given official recognition in 1932. It was slightly simplified upon the formation of the modern municipality in 1971 (registered with the Swedish Patent and Registration Office. in 1988).
- Claimed to have been designed by Robin Morgan in the 1960s. "Morgan designed the universal logo of the women’s movement, the woman’s symbol centered with a raised fist" (robinmorgan.net)
- Neugebauer, Otto; Van Hoesen, H. B. (1987). Greek Horoscopes. pp. 1, 159, 163.
- "At the same time as VOLVO was reactivated, the ancient chemical symbol for iron, a circle with an arrow pointing diagonally upwards to the right, was adopted as a logotype." (volvoclub.org.uk)
- Maunder (1934), p. 244.
- Pat Ward, Barbara Ward, Space Frontiers, Grades 4 - 8: EXPLORING Astronomy, Carson-Dellosa Publishing, 22 Oct 2012 p. 42 (without further reference).
- Maunder, A. S. D. (1934). "The origin of the symbols of the planets". The Observatory. 57: 238–247. Bibcode:1934Obs....57..238M.