The Nommo are ancestral spirits (sometimes referred to as deities) worshipped by the Dogon tribe of Mali. The word Nommos is derived from a Dogon word meaning "to make one drink." The Nommos are usually described as amphibious, hermaphroditic, fish-like creatures. Folk art depictions of the Nommos show creatures with humanoid upper torsos, legs/feet, and a fish-like lower torso and tail. The Nommos are also referred to as “Masters of the Water”, “the Monitors”, and "the Teachers”. Nommo can be a proper name of an individual, or can refer to the group of spirits as a whole. For purposes of this article “Nommo” refers to a specific individual and “Nommos” is used to reference the group of beings.
Nommo mythology 
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Dogon mythology says that Nommo was the first living creature created by the sky god Amma. Shortly after his creation, Nommo underwent a transformation and multiplied into four pairs of twins. One of the twins rebelled against the universal order created by Amma. To restore order to his creation, Amma sacrificed another of the Nommo progeny, whose body was dismembered and scattered throughout the universe. This dispersal of body parts is seen by the Dogon as the source for the proliferation of Binu shrines throughout the Dogons’ traditional territory; wherever a body part fell, a shrine was erected.
In the latter part of the 1940s, French anthropologists Marcel Griaule and Germaine Dieterlen (who had been working with the Dogon since 1931) were the recipients of additional, secret mythologies, concerning the Nommo. The Dogon reportedly related to Griaule and Dieterlen a belief that the Nommos were inhabitants of a world circling the star Sirius (see the main article on the Dogon for a discussion of their astronomical knowledge). The Nommos descended from the sky in a vessel accompanied by fire and thunder. After arriving, the Nommos created a reservoir of water and subsequently dove into the water. The Dogon legends state that the Nommos required a watery environment in which to live. According to the myth related to Griaule and Dieterlen: "The Nommo divided his body among men to feed them; that is why it is also said that as the universe "had drunk of his body," the Nommo also made men drink. He gave all his life principles to human beings." The Nommo are also thought to be the origin of the first Hogon.
||This article may be unbalanced towards certain viewpoints. (December 2010)|
In the 1970s a book by Robert Temple titled The Sirius Mystery popularized the traditions of the Dogon concerning Sirius and the Nommos. In The Sirius Mystery, Temple advanced the conclusion that the Dogon’s knowledge of astronomy and non-visible cosmic phenomenon could only be explained if this knowledge had been imparted upon them by an extraterrestrial race that had visited the Dogon at some point in the past. Temple related this race to the legend of the Nommos and contended that the Nommos were extraterrestrial inhabitants of the Sirius star system who had traveled to earth at some point in the distant past and had imparted knowledge about the Sirius star system as well as our own Solar System upon the Dogon tribes.
Walter van Beek, an anthropologist studying the Dogon, found no evidence that they had any historical advanced knowledge of Sirius. Van Beek postulated that Griaule engaged in such leading and forceful questioning of his Dogon sources that new myths were created in the process by confabulation, writing that
"though they do speak about sigu tolo [what Griaule claimed was Sirius] they disagree completely with each other as to which star is meant; for some it is an invisible star that should rise to announce the sigu [festival], for another it is Venus that, through a different position, appears as sigu tolo. All agree, however, that they learned about the star from Griaule".
Carl Sagan has noted that the first reported association of the Dogon with the knowledge of Sirius as a binary star was in the 1940s, giving the Dogon ample opportunity to gain cosmological knowledge about Sirius and the solar system from more scientifically advanced, terrestrial societies whom they had come in contact with. It has also been pointed out that binary star systems like Sirius are theorized to have a very narrow or non-existent Habitable zone, and thus a high improbability of containing a planet capable of sustaining life (particularly life as dependent on water as the Nommos were reported to be).
Daughter and colleague of Marcel Griaule, Genevieve Calame-Griaule, defended the project, dismissing Van Beek's criticism as misguided speculation rooted in an apparent ignorance of esoteric tradition. Van Beek continues to maintain that Griaule was wrong and cites other anthropologists who also reject his work. The assertion that the Dogon knew of another star in the Sirius system, Emme Ya, or "larger than Sirius B but lighter and dim in magnitude" continues to be discussed. In 1995, gravitational studies indicated the possible existence of a red dwarf star circling around Sirius but further observations have failed to confirm this. Space journalist and skeptic James Oberg collected claims that have appeared concerning Dogon mythology in his 1982 book and concedes that such assumptions of recent acquisition is "entirely circumstantial" and has no foundation in documented evidence and concludes that it seems likely that the Sirius mystery will remain exactly what its title implies; a mystery. Earlier, other critics such as the astronomer Peter Pesch and his collaborator Roland Pesch and Ian Ridpath had attributed the supposed "advanced" astronomical knowledge of the Dogon to a mixture of over-interpretation by commentators and cultural contamination.
References in fiction 
The belief structure surrounding Nommo, as well as Robert Temple's conclusion from The Sirius Mystery, were used by Larry Niven and Steven Barnes as the background for the role-playing game in The California Voodoo Game, the third volume in their Dream Park series. Novelist Tom Robbins discusses Nommo and the Sirius mysteries in his novel Half Asleep in Frog Pajamas. Nommo and the Dogon are also widely mentioned in Philip K. Dick's novel V.A.L.I.S.. The Nommo are also mentioned in the second book of Ian Douglas's Legacy Trilogy (Battlespace) where the marines encounter the Nommo in the Sirius star system. There are also references to the Nommo in Grant Morrison's comic book series, The Invisibles.
- "Dogon". Retrieved 26 March 2011.
- Imperato, Pascal James (2001). Legends, sorcerers, and enchanted lizards: door locks of the Bamana of Mali. Africana Publishing. ISBN 978-0-8419-1414-8.
- Temple, Robert K. G. The Sirius Mystery. New York: St. Martin's Press (1976).
- Walter E. A. van Beek: "Dogon Restudied: A Field Evaluation of the Work of Marcel Griaule." Current Anthropology, 32 (1991): 139-167.
- Genevieve Calame-Griaule: "On the Dogon Restudied." Current Anthropology, Vol. 32, No. 5 (Dec., 1991), pp. 575-577
- van Beek, Walter E. A., "Haunting Griaule: Experiences from the Restudy of the Dogon" History in Africa, Vol. 31. (2004), pp. 43-68.
- Benest, D., & Duvent, J. L. (1995) "Is Sirius a triple star?". Astronomy and Astrophysics 299: 621-628
- Bonnet-Bidaud, J. M.; Colas, F.; Lecacheux, J. (August 2000). "Search for companions around Sirius". Astronomy and Astrophysics 360: 991–996. arXiv:astro-ph/0010032. Bibcode:2000A&A...360..991B.
- James Oberg, "Chapter 6, The Sirius Mystery", in UFOs and Outer Space Mysteries, (1982) Donning Press
- P. and R. Pesch. "The Dogon and Sirius". Retrieved 2007-10-17.
- Ian Ridpath, Skeptical Inquirer, Fall 1978