Cydonia (Mars)

Coordinates: 40°44′N 9°28′W / 40.74°N 9.46°W / 40.74; -9.46
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Small part of the Cydonia region, taken by the Viking 1 orbiter and released by NASA/JPL on July 25, 1976

Cydonia (/sɪˈdniə/, /sˈdniə/) is a region on the planet Mars that has attracted both scientific[1] and popular interest.[2][3] The name originally referred to the albedo feature (distinctively coloured area) that was visible from earthbound telescopes. The area borders the plains of Acidalia Planitia and the highlands of Arabia Terra.[4] The region includes the named features Cydonia Mensae, an area of flat-topped mesa-like features; Cydonia Colles, a region of small hills or knobs; and Cydonia Labyrinthus, a complex of intersecting valleys.[5][6] As with other albedo features on Mars, the name Cydonia was drawn from classical antiquity, in this case from Kydonia (Ancient Greek: Κυδωνία; Latin: Cydonia), a historic polis (city state) on the island of Crete.[7] Cydonia contains the "Face on Mars", located about halfway between the craters Arandas and Bamberg.[4]


Cydonia lies in the planet's northern hemisphere in a transitional zone between the heavily cratered regions to the south and relatively smooth plains to the north. Some planetologists believe that the northern plains may once have been ocean beds,[8] and that Cydonia may once have been a coastal zone.[9] It is in the Mare Acidalium quadrangle.

Satellite picture of Cydonia
Picture of the Cydonia region taken in 2006 by The European Space Agency's satellite Mars Express. "Face on Mars" is just below the center.

"Face on Mars"[edit]

Cropped version of the original batch-processed image (#035A72) of the "Face on Mars". The black dots that give the image a speckled appearance are data errors (salt-and-pepper noise).[10]
Second Viking 1 image of the Cydonia region on Mars. Labeled 070A13

Cydonia was first imaged in detail by the Viking 1 and Viking 2 orbiters. Eighteen images of the Cydonia region were taken by the orbiters, of which seven have resolutions better than 250 m/pixel (820 ft/pixel). The other eleven images have resolutions that are worse than 550 m/pixel (1800 ft/pixel) and are of limited use for studying surface features. Of the seven good images, the lighting and time at which two pairs of images were taken are so close as to reduce the number to five distinct images. The Mission to Mars: Viking Orbiter Images of Mars CD-ROM set image numbers for these are: 035A72 (VO-1010), 070A13 (VO-1011), 561A25 (VO-1021), 673B54 & 673B56 (VO-1063), and 753A33 & 753A34 (VO-1028).[11][12]

In one of the images taken by Viking 1 on July 25, 1976, a two-kilometre-long (1.2 mi) Cydonian mesa, situated at 40.75° north latitude and 9.46° west longitude,[13] had the appearance of a humanoid face. When the image was originally acquired, Viking chief scientist Gerry Soffen dismissed the "Face on Mars" in image 035A72[14] as a "trick of light and shadow".[15][16] A second image, 070A13, also shows the "face", and was acquired 35 Viking orbits later at a different sun-angle from the 035A72 image. This latter discovery was made independently by Vincent DiPietro and Gregory Molenaar, two computer engineers at NASA's Goddard Space Flight Center. DiPietro and Molenaar discovered the two misfiled images, Viking frames 035A72 and 070A13, while searching through NASA archives.[17] The resolution of these images was of about 50 m/pixel.[18]

Later imagery[edit]

More than 20 years after the Viking 1 images were taken, a succession of spacecraft visited Mars and made new observations of the Cydonia region. These spacecraft have included NASA's Mars Global Surveyor (1997–2006) and Mars Reconnaissance Orbiter (2006–),[19] and the European Space Agency's Mars Express probe (2003–).[20] In contrast to the relatively low resolution of the Viking images of Cydonia, these new platforms afford much improved resolution. For instance, the Mars Express images are at a resolution of 14 m/pixel (46 ft/pixel) or better. By combining data from the High Resolution Stereo Camera (HRSC) on the Mars Express probe and the Mars Orbiter Camera (MOC) on board NASA's Mars Global Surveyor it has been possible to create a three-dimensional representation of the "Face on Mars".[21]

Mars Reconnaissance Orbiter image by its HiRISE camera of the "Face on Mars" (2007). Viking Orbiter image inset in bottom right corner (1976).
Mars Global Surveyor image (MOC camera) of the same feature (2001).
One of many formations in Cydonia, this one is sometimes called the "D & M pyramid".[22][23]

Since it was originally first imaged, the face has been accepted by scientists as an optical illusion, an example of the psychological phenomenon of pareidolia.[24][25][26] After analysis of the higher resolution Mars Global Surveyor data NASA stated that "a detailed analysis of multiple images of this feature reveals a natural looking Martian hill whose illusory face-like appearance depends on the viewing angle and angle of illumination".[27] Similar optical illusions can be found in the geology of Earth;[28] examples include the Old Man of the Mountain, the Romanian Sphinx, Giewont, the Pedra da Gávea, the Old Man of Hoy, Stac Levenish, Sleeping Ute, and the Badlands Guardian.[29]


The Cydonia facial pareidolia inspired individuals and organizations interested in extraterrestrial intelligence and visitations to Earth, and the images were published in this context in 1977.[30][31] Some commentators, most notably Richard C. Hoagland, believe the "Face on Mars" to be evidence of a long-lost Martian civilization along with other features they believe are present, such as apparent pyramids, which they argue are part of a ruined city.[32]

While accepting the "face" as a subject for scientific study, astronomer Carl Sagan criticized much of the speculation concerning it in the chapter "The Man in the Moon and the Face on Mars" in his 1995 book The Demon-Haunted World.[33][34] The shape-from-shading work by Mark J. Carlotto was used by Sagan in a chapter of his famous Cosmos series.[35] In 1998 a news article about the "Space Face" quoted a scientist talking about deciphering "intelligent design" in nature. A cutting of this was used by Charles Thaxton as an overhead visual for a lecture at Princeton, in his first public use of the term "intelligent design" as a substitute for creation science.[36]

The "face" is also a common topic among skeptics groups, who use it as an example of credulity.[37] They point out that there are other faces on Mars but these do not elicit the same level of study. One example is the Galle Crater, which takes the form of a smiley, while others resemble Kermit the Frog or other celebrities.[38] On this latter similarity, Discover magazine's "Skeptical Eye" column ridiculed Hoagland's claims, asking if he believed the aliens were fans of Sesame Street.[17][39]

Interactive Mars map[edit]

Map of MarsAcheron FossaeAcidalia PlanitiaAlba MonsAmazonis PlanitiaAonia PlanitiaArabia TerraArcadia PlanitiaArgentea PlanumArgyre PlanitiaChryse PlanitiaClaritas FossaeCydonia MensaeDaedalia PlanumElysium MonsElysium PlanitiaGale craterHadriaca PateraHellas MontesHellas PlanitiaHesperia PlanumHolden craterIcaria PlanumIsidis PlanitiaJezero craterLomonosov craterLucus PlanumLycus SulciLyot craterLunae PlanumMalea PlanumMaraldi craterMareotis FossaeMareotis TempeMargaritifer TerraMie craterMilankovič craterNepenthes MensaeNereidum MontesNilosyrtis MensaeNoachis TerraOlympica FossaeOlympus MonsPlanum AustralePromethei TerraProtonilus MensaeSirenumSisyphi PlanumSolis PlanumSyria PlanumTantalus FossaeTempe TerraTerra CimmeriaTerra SabaeaTerra SirenumTharsis MontesTractus CatenaTyrrhen TerraUlysses PateraUranius PateraUtopia PlanitiaValles MarinerisVastitas BorealisXanthe Terra
The image above contains clickable linksInteractive image map of the global topography of Mars. Hover your mouse over the image to see the names of over 60 prominent geographic features, and click to link to them. Coloring of the base map indicates relative elevations, based on data from the Mars Orbiter Laser Altimeter on NASA's Mars Global Surveyor. Whites and browns indicate the highest elevations (+12 to +8 km); followed by pinks and reds (+8 to +3 km); yellow is 0 km; greens and blues are lower elevations (down to −8 km). Axes are latitude and longitude; Polar regions are noted.

See also[edit]


  1. ^ Carlotto, Mark J. (May 15, 1988). "Digital Imagery Analysis of Unusual Martian Surface Features" (PDF). Applied Optics. 27 (10): 1926–1933. Bibcode:1988ApOpt..27.1926C. CiteSeerX doi:10.1364/AO.27.001926. ISSN 0003-6935. PMID 20531684. Retrieved April 19, 2013.
  2. ^ Whitehouse, David (May 25, 2001). "Nasa: No face – honest". BBC News. London. Retrieved November 9, 2007.
  3. ^ Britt, Robert Roy (September 22, 2006). "Face on Mars gets makeover". Retrieved November 9, 2007.
  4. ^ a b "Cydonia – the face on Mars". ESA. September 21, 2006. Retrieved April 19, 2013.
  5. ^ "Planetary Names: Mars". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program. Retrieved April 19, 2013.
  6. ^ "Planetary Names: Feature Types". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program. Retrieved April 19, 2013.
  7. ^ MacDonald, T. L. (October 1971). "The origins of Martian nomenclature". Icarus. 15 (2): 233–240. Bibcode:1971Icar...15..233M. doi:10.1016/0019-1035(71)90077-7.
  8. ^ Head III, J.W.; Kreslavsky, M.; Hiesinger, H.; Ivanov, M.; Pratt, Stephen; Seibert, N.; Smith, D.E.; Zuber, M.T. (December 15, 1998). "Oceans in the past history of Mars: Tests for their presence using Mars Orbiter Laser Altimeter (MOLA) data". Geophysical Research Letters. 25 (24): 4401–4404. Bibcode:1998GeoRL..25.4401H. doi:10.1029/1998GL900116. S2CID 9137761.
  9. ^ Malin, Michael C.; Edgett, Kenneth S. (October 1, 1999). "Oceans or seas in the Martian northern lowlands: High resolution imaging tests of proposed coastlines". Geophysical Research Letters. 26 (19): 3049–3052. Bibcode:1999GeoRL..26.3049M. CiteSeerX doi:10.1029/1999GL002342. S2CID 53411196.
  10. ^ "PIA01141: Geologic 'Face on Mars' Formation". NASA. April 2, 1998. Retrieved February 12, 2011.
  11. ^ "Mission to Mars: Viking Orbiter Images of Mars (Experiment Data Records)". PDS Imaging Node. NASA/JPL/USGS. Retrieved April 19, 2013. Raw data in the IMQ (ImageQ) format can be downloaded from these links: 035A72, 070A13, 561A25, 673B54, 673B56, 753A33, 753A34.
  12. ^ JPL; NASA; Viking Mars Program (U.S.) (1990). Mission to Mars: Viking Orbiter Images of Mars (CD-ROM). Pasadena, CA: JPL. OCLC 232381148.
  13. ^ Rayl, A.J.S. (March 16, 2007). "The Empire Strikes Back: Europe's First Trip to Mars Brings Home 'The Gold'". The Planetary Society. Archived from the original on March 4, 2012. Retrieved April 19, 2013.
  14. ^ "Viking 1–61 (35A72)". Viking News Center (Press release). Pasadena, CA: NASA/JPL. July 31, 1976. Retrieved April 19, 2013. Caption of JPL Viking Press Release P-17384.
  15. ^ Hoagland, Richard C. (1996). The Monuments of Mars: A City on the Edge of Forever (4th ed.). Berkeley: Frog, Ltd. p. 5. ISBN 978-1-883319-30-4.
  16. ^ Paranormal News Staff (August 25, 1999). "Pixel Inversion – NASA's Misinformation on the Mars Face". Paranormal News. Jeff Behnke. Archived from the original on June 12, 2008. Retrieved May 29, 2008.
  17. ^ a b Gardner, Martin (Winter 1985–1986). "The Great Stone Face and Other Nonmysteries" (PDF). Skeptical Inquirer. 10 (2): 14–18. Retrieved April 22, 2021.
  18. ^ "Viking: 035A72". Mars Image Explorer. Retrieved July 3, 2019. Line Resolution 0.048049 km
  19. ^ "Popular Landform in Cydonia Region". HiRISE website. Retrieved April 22, 2021.
  20. ^ "Cydonia – the face on Mars". ESA. September 21, 2006. Retrieved April 26, 2007.
  21. ^ "Cydonia's 'Face on Mars' in 3D animation". ESA. October 23, 2006. Retrieved April 26, 2007.
  22. ^ "Cydonia: Two Years Later". Malin Space Science Systems. April 5, 2000. Retrieved December 1, 2008.
  23. ^ Fitzpatrick-Matthews, Keith (August 17, 2007). "Alien archaeology on Mars?: The 'D&M Pyramid". Bad Archaeology. Keith Fitzpatrick-Matthews and James Doeser. Retrieved December 1, 2008.
  24. ^ Britt, Robert Roy (March 18, 2004). "Scientist attacks alien claims on Mars". CNN. Retrieved October 12, 2007.
  25. ^ Normand Baillargeon, A Short Course in Intellectual Self Defense: Find Your Inner Chomsky, p. 177 (Seven Stories Press, 2007). ISBN 978-1-58322-765-7
  26. ^ Charles M. Wynn, Arthur W. Wiggins, Quantum Leaps in the Wrong Direction: Where Real Science Ends... and Pseudoscience begins (Joseph Henry Press, 2001). ISBN 0-309-17135-0
  27. ^ "The Face on Mars". Image of the Day Gallery. NASA. Retrieved April 26, 2007.
  28. ^ Dunning, Brian (April 22, 2008). "Skeptoid #97: The Face on Mars Revealed – New high resolution imagery has proven that this hill on Mars doesn't look quite so much like a carved face after all". Skeptoid.
  29. ^ "Badlands Guardian Geological Feature". Google Maps. Retrieved April 26, 2007.
  30. ^ Smukler, H. (1977). "Dramatic Photos of Mars: the Home of the Gods". Ancient Astronauts (January): 26.
  31. ^ Grossinger, Richard, ed. (1986). Planetary Mysteries: Megaliths, Glaciers, the Face on Mars and Aboriginal Dreamtime. Berkeley: North Atlantic Books. p. 11. ISBN 978-0-938190-90-5. Retrieved August 12, 2008.
  32. ^ Hoagland, Richard (2002). The Monuments of Mars: A City on the Edge of Forever (5 ed.). North Atlantic Books, U.S. ISBN 978-1-58394-054-9.
  33. ^ Sagan, Carl (1995). The Demon-Haunted World: Science As a Candle in the Dark. New York: Random House. ISBN 978-0-394-53512-8.
  34. ^ McDaniel, Stanley; Paxson, Monica Rix, eds. (1998). The Case for the Face: Scientists Examine The Evidence for Alien Artifacts on Mars (1st ed.). Adventure Unlimited Press. ISBN 978-0-932813-59-6.
  35. ^ "Carl Sagan and The Face on Mars". YouTube. Archived from the original on November 17, 2021.
  36. ^ Witham, Larry (2005). Where Darwin Meets the Bible: Creationists and Evolutionists in America. Oxford University Press. p. 221. ISBN 978-0-19-518281-1.
  37. ^ Posner, Gary P. (November–December 2000). "The Face Behind the 'Face' on Mars: A Skeptical Look at Richard C. Hoagland". Skeptical Inquirer. 24 (6): 20–26. Retrieved April 28, 2013.
  38. ^ "More 'Faces' on Mars". Tampa Bay Skeptics. Retrieved April 20, 2013.
  39. ^ Golden, Fred (April 1985). "Skeptical Eye". Discover.

External links[edit]

Non-Space Agency

40°44′N 9°28′W / 40.74°N 9.46°W / 40.74; -9.46