The Nibiru collision is a supposed encounter between the Earth and a large planetary object (either a collision or a near-miss) which certain groups believe will take place in the early 21st century. Believers in this doomsday event usually refer to this object as Planet X or Nibiru.

The idea was first proposed in 1995 by Nancy Lieder, founder of the website ZetaTalk. Lieder describes herself as a contactee with the ability to receive messages from extra-terrestrials from the Zeta Reticuli star system through an implant in her brain. She states that she was chosen to warn mankind that the object would sweep through the inner Solar System in May 2003, later revised to around 2010, causing Earth to undergo a pole shift that would destroy most of humanity. The predicted collision has subsequently spread beyond Lieder's website and has been embraced by numerous internet doomsday groups, most of which link the event to the 2012 phenomenon. Although the name "Nibiru" is derived from the works of ancient astronaut writer Zecharia Sitchin and his interpretations of Babylonian and Sumerian mythology, Sitchin himself denies any connection between his work and claims of a coming apocalypse.

The idea that a planet-sized object could possibly collide with Earth in the near future is not supported by any scientific evidence and has been roundly rejected as pseudoscience by astronomers and planetary scientists.

Origins

The idea of the Nibiru collision originated with Nancy Lieder, a Wisconsin woman who claims that as a girl she was contacted by gray extraterrestrials called Zetas, who implanted a communications device in her brain. In 1995, she founded the website ZetaTalk to disseminate her ideas. Lieder first came to public attention on internet newsgroups during the build-up to Comet Hale-Bopp's 1997 perihelion. She stated, speaking as the Zetas, that "The Hale-Bopp comet does not exist. It is a fraud, perpetrated by those who would have the teeming masses quiescent until it is too late. Hale-Bopp is nothing more than a distant star, and will draw no closer." She claimed that the Hale-Bopp story was manufactured to distract people from the imminent arrival of a large planetary object, "Planet X", which would soon pass by Earth and destroy civilization. After Hale-Bopp's perihelion revealed it as one of the brightest and longest-observed comets of the last century, Lieder removed the first two sentences of her initial statement from her site, though they can still be found in Google's archives. Her claims eventually made the New York Times.

Lieder described Planet X as roughly four times the size of the Earth, and said that its perigee would occur on May 27, 2003, resulting in the Earth's rotation ceasing for exactly 5.9 terrestrial days. This would be followed by the Earth's pole destabilising in a pole shift (a physical pole shift, with the Earth's pole physically moving, rather than a geomagnetic reversal) caused by magnetic attraction between the Earth's core and the magnetism of the passing planet. This in turn would disrupt the Earth's magnetic core and lead to subsequent displacement of the Earth's crust.

After the 2003 date passed without incident, Lieder said that it was merely a "White Lie ... to fool the establishment,"and said that to disclose the true date would give those in power enough time to declare martial law and trap people in cities during the shift, leading to their deaths. She still insists that the Zetas tell her that Planet X is coming and that a more specific passage timeline will be forthcoming possibly by mid-2010.

Lieder's Planet X idea first spread beyond her website in 2001, when Mark Hazlewood, a former member of the ZetaTalk community, took her ideas and published them in a book: Blindsided: Planet X Passes in 2003. Lieder would later accuse him of being a confidence trickster.

Japanese cult the Pana Wave Laboratory, which famously blocked off roads and rivers with white cloths to protect itself from electromagnetic attacks, also warned that the world would end in May 2003 after the approach of a tenth planet.

Many internet sites continue to proclaim that "Planet X" or "Nibiru" is en route to Earth, often citing its arrival date as December, 2012. This date has gathered many apocalyptic associations, as it is the end of the current cycle (baktun) in the long count in the Mayan calendar. Several writers have published books connecting the Nibiru collision with 2012, including Marshall Masters and Jaysen Rand. Hazlewood has since changed his views on Planet X, and now says that there are intelligent alien forces acting to protect us as a species, and that we are set to ascend to a higher level of consciousness in 2012.

Names

Although Lieder originally referred to the object as "Planet X", it has become deeply associated with Nibiru, a planet from the works of ancient astronaut proponent Zecharia Sitchin, particularly his book The 12th Planet. According to Sitchin's interpretation of Babylonian religious texts, which contravenes every conclusion reached by credited scholars on the subject, a giant planet (Nibiru or Marduk) passes by Earth every 3,600 years and allows its sentient inhabitants to interact with humanity. These beings, which Sitchin identifies with the Annunaki of Sumerian myth, would become humanity's first gods. However, Sitchin denies any connection between his work and Lieder's claims, and it was Lieder who initially made the connection on her site ("Planet X does exist, and it is the 12th Planet, one and the same."). In 2007, partly in response to Lieder's proclamations, Sitchin published a book, The End of Days, which set the time for the last passing of Nibiru by Earth at roughly 600 BC, which would mean, given the object's supposed 3,600–year orbit, it would be unlikely to return in less than 1,000 years.

Leider drew the name Planet X from the hypothetical planet once searched for by astronomers to account for discrepancies in the orbits of Uranus and Neptune. In 1894, Bostonian astronomer Percival Lowell became convinced that the planets Uranus and Neptune had slight discrepancies in their orbits. He concluded that they must be being tugged by the gravity of another, more distant planet, which he called "Planet X". However, nearly a century of searching failed to turn up any evidence for such an object (Pluto was initially believed to be Planet X, but was later determined to be too small). In 1992, astronomer Myles Standish showed that the supposed discrepancies in the planets' orbits were illusory; the product of an overestimation of the mass of Neptune. Today astronomers accept that Planet X does not exist.

Still others refer to Lieder's object as Eris; however, Eris is a dwarf planet only slightly larger than Pluto with a well-determined orbit that never takes it closer than 5.5 billion km from the Earth. Astronomer Mike Brown, who discovered Eris, believes the confusion results from both the real Eris and the imaginary Nibiru having extremely elliptical orbits.

Scientific criticism

Astronomers point out that such an object so close to Earth would be easily visible to the naked eye (Jupiter and Saturn are both visible to the naked eye, and are dimmer than Nibiru would be at their distances), and would be creating noticeable effects in the orbits of the outer planets. Some counter this by claiming that the object has been hiding behind the Sun for several years, though such a claim is geometrically impossible. Images of Nibiru near the Sun taken by amateurs are usually of lens flares, false images of the Sun created by reflections within the lens.

Mike Brown notes that if this object's orbit were as described, it would only have lasted in the Solar System for a million years or so before Jupiter expelled it, and that there is no way another object's magnetic field could have such an effect on Earth. Lieder's assertions that the approach of Nibiru would cause the Earth's rotation to stop or its axis to shift violate the laws of physics. In his rebuttal of Immanuel Velikovsky's Worlds in Collision, which made the same claim that the Earth's rotation could be stopped and then restarted, Carl Sagan noted that, "the energy required to brake the Earth is not enough to melt it, although it would result in a noticeable increase in temperature: the oceans would [be] raised to the boiling point of water . . . [Also,] how does the Earth get started up again, rotating at approximately the same rate of spin? The Earth cannot do it by itself, because of the law of the conservation of angular momentum."

Many believers in the imminent approach of Planet X/Nibiru accuse NASA of deliberately covering up visual evidence of its existence. One such accusation involves the IRAS infrared space observatory, launched in 1983. The satellite briefly made headlines due to an "unknown object" that was at first described as "possibly as large as the giant planet Jupiter and possibly so close to Earth that it would be part of this Solar System". This newspaper article has been cited by proponents of the collision idea, beginning with Leider herself, as evidence for the existence of Nibiru. However, further analysis revealed that of several unidentified objects, nine were distant galaxies and the tenth was "intergalactic cirrus"; none were found to be Solar System bodies.

Another accusation frequently made by websites predicting the collision is that the US government built the South Pole Telescope to track Nibiru's trajectory, and that the object has been imaged optically. However, the SPT (which is not funded by NASA) is a radio telescope, and cannot take optical images. Its South Pole location was chosen due to the low-humidity environment, and there is no way an approaching object could be seen only from the South Pole. The "picture" of Nibiru posted on YouTube was revealed to in fact be a Hubble image of the expanding gas shell around the star V838 Mon.

Public reaction

The impact of the public fear of a Nibiru collision has been especially felt by professional astronomers. Mike Brown now says that Nibiru is the most common pseudoscientific topic he is asked about.

David Morrison, a CSI Fellow and Senior Scientist at NASA's Astrobiology Institute at Ames Research Center, says he receives 20–25 emails a week about the impending arrival of Nibiru; some frightened, others angry and naming him as part of the conspiracy to keep the truth of the impending apocalypse from the public. Half of these emails are from outside the US. "Planetary scientists are being driven to distraction by Nibiru," notes science writer Govert Schilling, "And it is not surprising; you devote so much time, energy and creativity to fascinating scientific research, and find yourself on the tracks of the most amazing and interesting things, and all the public at large is concerned about is some crackpot theory about clay tablets, god-astronauts and a planet that doesn't exist." Morrison states that he hopes that the non-arrival of Nibiru could serve as a teaching moment for the public, instructing them on 'rational thought and baloney detection', but doubts that will happen.

A viral campaign for Sony Pictures' 2009 film 2012, directed by Roland Emmerich, which depicts the end of the world in that year, features a supposed warning from the "Institute for Human Continuity" that lists the arrival of Planet X as one of its doomsday scenarios. Mike Brown attributes a spike in concerned emails and phone calls he received from the public to this site.

Zecharia Sitchin (born 1922) is an author of books promoting an explanation for human origins involving ancient astronauts, amidst other aspects of pseudoscience.

Sitchin attributes the creation of the ancient Sumerian culture to the "Anunnaki", a race of aliens from a planet he calls Nibiru, which he believes to be in an elongated, elliptical orbit in the Earth's own Solar System and asserts that Sumerian mythology reflects this view.

His speculations are entirely discounted by professional scientists, historians, and archaeologists, who note many problems with his translations of ancient texts and with his understanding of physics.

Life

Sitchin was born in Baku, Azerbaijan, and was raised in Palestine. He acquired some knowledge of modern and ancient Hebrew, other Semitic and European languages, the Torah, and the history and archeology of the Near East. Sitchin graduated from the London School of Economics, University of London, majoring in economic history. A journalist and editor in Israel for many years, he now lives and writes in New York City. His books have been widely translated, converted to braille for the blind, and featured on radio and television.

Ideas

According to Sitchin's interpretation of Sumerian cosmology, there is an undiscovered planet which follows a long, elliptical orbit, reaching the inner solar system roughly every 3,600 years. This planet is called Nibiru (the planet associated with the god Marduk in Babylonian cosmology). According to Sitchin, Nibiru collided catastrophically with Tiamat, another supposed planet located by Sitchin between Mars and Jupiter. This collision supposedly formed the planet Earth, the asteroid belt, and the comets. Tia mat, as outlined in the Enûma Elish, is a goddess. According to Sitchin, however, Tiamat was what is now known as Earth. When struck by one of planet Nibiru's moons, Tiamat split in two. On a second pass Nibiru itself struck the broken fragments and one half of Tiamat became the asteroid belt. The second half, struck again by one of Nibiru's moons, was pushed into a new orbit and became today's planet Earth.

According to Sitchin, Nibiru was the home of a technologically advanced human-like extraterrestrial race called the Anunnaki in Sumerian myth, who Sitchin states are called the Nephilim in Genesis. He claims they first arrived on Earth probably 450,000 years ago, looking for minerals, especially gold, which they found and mined in Africa. These "gods" were the rank and file workers of the colonial expedition to Earth from planet Nibiru. Sitchin believes the Anunnaki genetically engineered Homo sapiens as slave creatures to work their gold mines by crossing extraterrestrial genes with those of Homo erectus. Sitchin claims ancient inscriptions report that human civilization in Sumer of Mesopotamia was set up under the guidance of these "gods", and human kingship was inaugurated to provide intermediaries between mankind and the Anunnaki. Sitchin believes that fallout from nuclear weapons, used during a war between factions of the extraterrestrials, is the "evil wind" that destroyed Ur around 2000 BC. Sitchin claims the exact year is 2024 BC. This event is described in the Lament for Ur. Sitchin claims that his research coincides with many biblical texts, and that biblical texts come originally from Sumerian writings.

Criticisms

When Sitchin wrote his books, only specialists could read the Sumerian language, but now anyone can check his translations by utilizing the 2006 book Sumerian Lexicon. Sitchin's translations of both individual words and of larger portions of ancient texts are generally found to be incorrect.

Sitchin's "planetary collision" view does superficially resemble a theory which is seriously entertained by modern astronomers — the giant impact theory of the Moon's formation about 4.5 billion years ago by a body impacting with the newly-formed Earth. However, Sitchin's proposed series of rogue planetary collisions differ in both details and timing. As with Immanuel Velikovsky's earlier Worlds in Collision thesis, Sitchin claims to have found evidence of ancient human knowledge of rogue celestial motions in a variety of mythological accounts. In Velikovsky's case, these interplanetary collisions were supposed to have taken place within the span of human existence, whereas for Sitchin these occurred during the early stages of planetary formation, but entered the mythological account passed down via the alien race which purportedly evolved on Nibiru after these encounters.

Sitchin's scenario for the creation of the Solar System is hard to reconcile with the Earth's current small orbital eccentricity of only 0.0167. Sitchin's supporters maintain that it would explain Earth's peculiar early geography due to cleaving from the celestial collision, i.e., solid continents on one side and a giant ocean on the other.

The scenario outlined by Sitchin, with Nibiru returning to the inner solar system regularly every 3,600 years, implies an orbit with a semi-major axis of 235 Astronomical Units, extending from the asteroid belt to twelve times farther beyond the sun than Pluto. "Elementary perturbation theory indicates that, under the most favorable circumstances of avoiding close encounters with other planets, no body with such an eccentric orbit would keep the same period for two consecutive passages. Within twelve orbits the object would be either ejected or converted to a short period object. Thus, the failed search for a trans-Plutonian planet by T.C. Van Flandern, then with the U.S. Naval Observatory, which Sitchin uses to bolster his thesis, is no support at all."

Sitchin claims that "from an equal start, the Nefilim evolved on Nibiru 45 million years ahead of comparable development on Earth with its decidedly more favorable environment." Such an outcome is unlikely, to say the least, since Nibiru would spend over 99% of its time beyond Pluto. Sitchin's explanation that heat from radioactive decay and a thick atmosphere keep Nibiru warm is absurd and does not address the problem of darkness in deep space. Also unexplained is how the Nefilim, who evolved long after Nibiru arrived, knew what happened when Nibiru first entered the solar system.

Sitchin bases his arguments on his personal interpretations of Pre-Nubian and Sumerian texts, and the seal VA 243. Sitchin claims these ancient civilizations knew of a 12th planet, when in fact they only knew five. Hundreds of Sumerian astronomical seals and calendars have been decoded and recorded, and the total count of planets on each seal has been five. Seal VA 243 has 12 dots that Sitchin identifies as planets. When translated, seal VA 243 reads "You're his Servant" which is now thought to be a message from a nobleman to a servant. According to semitologist Michael S. Heiser, the so-called sun on Seal VA 243 is not the Sumerian symbol for the sun but is a star, and the dots are also stars. The symbol on seal VA 243 has no resemblance to the hundreds of documented Sumerian sun symbols.

Peter James has criticised him both for ignoring the world outside of Mesopotamia and more specifically for misunderstanding Babylonian literature:

“

He uses the Epic of Creation Enuma Elish as the foundation for his cosmogony, identifying the young god Marduk, who overthrows the older regime of gods and creates the Earth, as the unknown "Twelfth Planet". In order to do as he interprets the Babylonian theogony as a factual account of the birth of the other "eleven" planets. The Babylonian names for the planets are established beyond a shadow of a doubt--Ishtar was the deity of Venus, Nergal of Mars, and Marduk of Jupiter -- and confirmed by hundreds of astronomical/astrological tables and treatises on clay tablets and papyri from the Hellenistic period. Sitchin merrily ignores all this and assigns unwarranted planetary identities to the gods mentioned in the theogony. For example, Apsu, attested as god of the primeval waters becomes, of all things, the Sun! Ea, as it suits Sitchin, is sometimes planet Neptune and sometimes a spaceman. And the identity of Ishtar as the planet Venus, a central feature of Mesopotamian religion, is nowhere mentioned in the book--instead Sitchin arbitrarily assigns to Venus another deity from Enuma Elish, and reserves Ishtar for a role as a female astronaut.

”

Similar ideas have been advanced by authors such as Immanuel Velikovsky, Erich von Däniken, Alan F. Alford and Laurence Gardner. Alford later recanted his views and became a critic of Sitchin's interpretation of myth.

Sitchin in “the case of Adam’s alien genes” claims that 223 unique genes found by the Human Genome Sequencing Consortium are without the required predecessors on the genomic evolutionary tree. Later researchers have argued that the conclusion from the Human Genome Sequencing Consortium can not be drawn due to a lack of a comprehensive gene database for comparison. An analysis by Salzberg identified 40 potential genes laterally transferred into the genome from prokaryotic organisms. Salzberg also argues that gene loss combined with sample size effects and evolutionary rate variation provide an alternative, more biologically plausible explanation.

William Irwin Thompson comments on what he calls Sitchin's 'literalism':

What Sitchin sees is what he needs for his theory. So figure 15 on page 42 is radiation therapy, and figure 71 on page 136 is a god inside a rocket-shaped chamber. If these are gods, why are they stuck with our cheap B movie technology of rockets, microphones, space-suits, and radiation therapy? If they are gods, then why can't they have some really divine technology such as intradimensional worm-hole travel, antigravity, starlight propulsion, or black hole bounce rematerializations? Sitchin has constructed what appears to be a convincing argument, but when he gets close to single images on ancient tablets, he falls back into the literalism of "Here is an image of the gods in rockets." Suddenly, ancient Sumer is made to look like the movie set for Destination Moon. Erich Von Däniken's potboiler Chariots of the Gods has the same problem. The plain of Nazca in Peru is turned into a World War II landing strip. The gods can cross galactic distances, but by the time they get to Peru, their spaceships are imagined as World War II prop jobs that need an enormous landing strip. This literalization of the imagination doesn't make any sense, but every time it doesn't, you hear Sitchin say "There can be no doubt, but..."

Influence

Raëlism, the UFO religion founded by Claude Vorilhon, appropriated some of its beliefs from Sitchin's work, as does the Nuwaubian religion founded by Dwight York. Zetatalk, the internet cult founded by self-proclaimed contactee Nancy Leider, describes "Planet X", a large object they claim is about to hit Earth, as "Nibiru" in reference to Sitchin's claims. David Icke also draws on Sitchin's work in his conspiracy theories. The 1994 movie Stargate, directed by Roland Emmerich, drew some conceptual inspiration from Sitchin's ideas.

 

The Maya calendar is a system of distinct calendars and almanacs used by the Maya civilization of pre-Columbian Mesoamerica, and by some modern Maya communities in highland Guatemala and Oaxaca, Mexico.

The essentials of the Maya calendric system are based upon a system which had been in common use throughout the region, dating back to at least the 6th century BC. It shares many aspects with calendars employed by other earlier Mesoamerican civilizations, such as the Zapotec and Olmec, and contemporary or later ones such as the Mixtec and Aztec calendars. Although the Mesoamerican calendar did not originate with the Maya, their subsequent extensions and refinements of it were the most sophisticated. Along with those of the Aztecs, the Maya calendars are the best-documented and most completely understood.

By the Maya mythological tradition, as documented in Colonial Yucatec accounts and reconstructed from Late Classic and Postclassic inscriptions, the deity Itzamna is frequently credited with bringing the knowledge of the calendar system to the ancestral Maya, along with writing in general and other foundational aspects of Maya culture.

Overview

The most important of these calendars is the one with a period of 260 days. This 260-day calendar was prevalent across all Mesoamerican societies, and is of great antiquity (almost certainly the oldest of the calendars). It is still used in some regions of Oaxaca, and by the Maya communities of the Guatemalan highlands. The Maya version is commonly known to scholars as the Tzolkin, or Tzolk'in in the revised orthography of the Academia de las Lenguas Mayas de Guatemala. The Tzolk'in is combined with another 365-day calendar (known as the Haab, or Haab' ), to form a synchronized cycle lasting for 52 Haabs, called the Calendar Round. Smaller cycles of 13 days (the trecena) and 20 days (the veintena) were important components of the Tzolk'in and Haab' cycles, respectively.

A different form of calendar was used to track longer periods of time, and for the inscription of calendar dates (i.e., identifying when one event occurred in relation to others). This form, known as the Long Count, is based upon the number of elapsed days since a mythological starting-point. According to the correlation between the Long Count and Western calendars accepted by the great majority of Maya researchers (known as the GMT correlation), this starting-point is equivalent to August 11, 3114 BC in the proleptic Gregorian calendar or 6 September in the Julian calendar (−3113 astronomical). The Goodman-Martinez-Thompson correlation was chosen by Thompson in 1935 on the basis of earlier correlations by Joseph Goodman in 1905 (August 11), Juan Martínez Hernández in 1926 (August 12), and John Eric Sydney Thompson in 1927 (August 13). By its linear nature, the Long Count was capable of being extended to refer to any date far into the future (or past). This calendar involved the use of a positional notation system, in which each position signified an increasing multiple of the number of days. The Maya numeral system was essentially vigesimal (i.e., base-20), and each unit of a given position represented 20 times the unit of the position which preceded it. An important exception was made for the second-order place value, which instead represented 18 × 20, or 360 days, more closely approximating the solar year than would 20 × 20 = 400 days. It should be noted however that the cycles of the Long Count are independent of the solar year.

Many Maya Long Count inscriptions are supplemented by a Lunar Series, which provides information on the lunar phase and position of the Moon in a half-yearly cycle of lunations.

A 584-day Venus cycle was also maintained, which tracked the heliacal risings of Venus as the morning and evening stars. Many events in this cycle were seen as being astrologically inauspicious and baleful, and occasionally warfare was astrologically timed to coincide with stages in this cycle.

Other, less-prevalent or poorly understood cycles, combinations and calendar progressions were also tracked. An 819-day Count is attested in a few inscriptions. Repeating sets of 9-day and 13-day intervals associated with different groups of deities, animals, and other significant concepts are also known.

Maya concepts of time

With the development of the place-notational Long Count calendar (believed to have been inherited from other Mesoamerican cultures), the Maya had an elegant system with which events could be recorded in a linear relationship to one another, and also with respect to the calendar ("linear time") itself. In theory, this system could readily be extended to delineate any length of time desired, by simply adding to the number of higher-order place markers used (and thereby generating an ever-increasing sequence of day-multiples, each day in the sequence uniquely identified by its Long Count number). In practice, most Maya Long Count inscriptions confine themselves to noting only the first five coefficients in this system (a b'ak'tun-count), since this was more than adequate to express any historical or current date (20 b'ak'tuns cover 7,885 solar years). Even so, example inscriptions exist which noted or implied lengthier sequences, indicating that the Maya well understood a linear (past-present-future) conception of time.

However, and in common with other Mesoamerican societies, the repetition of the various calendric cycles, the natural cycles of observable phenomena, and the recurrence and renewal of death-rebirth imagery in their mythological traditions were important and pervasive influences upon Maya societies. This conceptual view, in which the "cyclical nature" of time is highlighted, was a pre-eminent one, and many rituals were concerned with the completion and re-occurrences of various cycles. As the particular calendaric configurations were once again repeated, so too were the "supernatural" influences with which they were associated. Thus it was held that particular calendar configurations had a specific "character" to them, which would influence events on days exhibiting that configuration. Divinations could then be made from the auguries associated with a certain configuration, since events taking place on some future date would be subject to the same influences as its corresponding previous cycle dates. Events and ceremonies would be timed to coincide with auspicious dates, and avoid inauspicious ones.

The completion of significant calendar cycles ("period endings"), such as a k'atun-cycle, were often marked by the erection and dedication of specific monuments (mostly stela inscriptions, but sometimes twin-pyramid complexes such as those in Tikal and Yaxha), commemorating the completion, accompanied by dedicatory ceremonies.

A cyclical interpretation is also noted in Maya creation accounts, in which the present world and the humans in it were preceded by other worlds (one to five others, depending on the tradition) which were fashioned in various forms by the gods, but subsequently destroyed. The present world also had a tenuous existence, requiring the supplication and offerings of periodic sacrifice to maintain the balance of continuing existence. Similar themes are found in the creation accounts of other Mesoamerican societies.

Tzolk'in

The tzolk'in (in modern Maya orthography; also commonly written tzolkin) is the name commonly employed by Mayanist researchers for the Maya Sacred Round or 260-day calendar. The word tzolk'in is a neologism coined in Yucatec Maya, to mean "count of days" (Coe 1992). The various names of this calendar as used by Precolumbian Maya peoples are still debated by scholars. The Aztec calendar equivalent was called Tonalpohualli, in the Nahuatl language.

The tzolk'in calendar combines twenty day names with the thirteen numbers of the trecena cycle to produce 260 unique days. It is used to determine the time of religious and ceremonial events and for divination. Each successive day is numbered from 1 up to 13 and then starting again at 1. Separately from this, every day is given a name in sequence from a list of 20 day names:

Some systems started the count with 1 Imix', followed by 2 Ik', 3 Ak'b'al, etc. up to 13 B'en. The trecena day numbers then start again at 1 while the named-day sequence continues onwards, so the next days in the sequence are 1 Ix, 2 Men, 3 K'ib', 4 Kab'an, 5 Etz'nab', 6 Kawoq, and 7 Ajau. With all twenty named days used, these now began to repeat the cycle while the number sequence continues, so the next day after 7 Ajaw is 8 Imix'. The repetition of these interlocking 13- and 20-day cycles therefore takes 260 days to complete (that is, for every possible combination of number/named day to occur once).

Origin of the Tzolk'in

The exact origin of the Tzolk'in is not known, but there are several theories. One theory is that the calendar came from mathematical operations based on the numbers thirteen and twenty, which were important numbers to the Maya. The numbers multiplied together equal 260. Another theory is that the 260-day period came from the length of human pregnancy. This is close to the average number of days between the first missed menstrual period and birth, unlike Naegele's rule which is 40 weeks (280 days) between the last menstrual period and birth. It is postulated that midwives originally developed the calendar to predict babies' expected birth dates.

A third theory comes from understanding of astronomy, geography and paleontology. The mesoamerican calendar probably originated with the Olmecs, and a settlement existed at Izapa, in southeast Chiapas Mexico, before 1200 BC. There, at a latitude of about 15° N, the Sun passes through zenith twice a year, and there are 260 days between zenithal passages, and gnomons (used generally for observing the path of the Sun and in particular zenithal passages), were found at this and other sites. The sacred almanac may well have been set in motion on August 13, 1359 BC, in Izapa. Vincent H. Malmström, a geographer who suggested this location and date, outlines his reasons:

(1) Astronomically, it lay at the only latitude in North America where a 260-day interval (the length of the "strange" sacred almanac used throughout the region in pre-Columbian times) can be measured between vertical sun positions -- an interval which happens to begin on the 13th of August -- the day the peoples of the Mesoamerica believed that the present world was created; (2) Historically, it was the only site at this latitude which was old enough to have been the cradle of the sacred almanac, which at that time (1973) was thought to date to the 4th or 5th centuries B.C.; and (3) Geographically, it was the only site along the required parallel of latitude that lay in a tropical lowland ecological niche where such creatures as alligators, monkeys, and iguanas were native -- all of which were used as day-names in the sacred almanac.

Malmström also offers strong arguments against both of the former explanations.

A fourth theory is that the calendar is based on the crops. From planting to harvest is approximately 260 days.

Haab'

The Haab' was the Maya solar calendar made up of eighteen months of twenty days each plus a period of five days ("nameless days") at the end of the year known as Wayeb' (or Uayeb in 16th C. orthography). Bricker (1982) estimates that the Haab' was first used around 550 BC with the starting point of the winter solstice.

The Haab' month names are known today by their corresponding names in colonial-era Yukatek Maya, as transcribed by 16th century sources (in particular, Diego de Landa and books such as the Chilam Balam of Chumayel). Phonemic analyses of Haab' glyph names in pre-Columbian Maya inscriptions have demonstrated that the names for these twenty-day periods varied considerably from region to region and from period to period, reflecting differences in the base language(s) and usage in the Classic and Postclassic eras predating their recording by Spanish sources.

Each day in the Haab' calendar was identified by a day number in the month followed by the name of the month. Day numbers began with a glyph translated as the "seating of" a named month, which is usually regarded as day 0 of that month, although a minority treat it as day 20 of the month preceding the named month. In the latter case, the seating of Pop is day 5 of Wayeb'. For the majority, the first day of the year was 0 Pop (the seating of Pop). This was followed by 1 Pop, 2 Pop as far as 19 Pop then 0 Wo, 1 Wo and so on.

As a calendar for keeping track of the seasons, the Haab' was a bit inaccurate, since it treated the year as having exactly 365 days, and ignored the extra quarter day (approximately) in the actual tropical year. This meant that the seasons moved with respect to the calendar year by a quarter day each year, so that the calendar months named after particular seasons no longer corresponded to these seasons after a few centuries. The Haab' is equivalent to the wandering 365-day year of the ancient Egyptians.

Wayeb'

The five nameless days at the end of the calendar, called Wayeb', were thought to be a dangerous time. Foster (2002) writes "During Wayeb, portals between the mortal realm and the Underworld dissolved. No boundaries prevented the ill-intending deities from causing disasters." To ward off these evil spirits, the Maya had customs and rituals they practiced during Wayeb'. For example, people avoided leaving their houses or washing or combing their hair.

Calendar Round

Neither the Tzolk'in nor the Haab' system numbered the years. The combination of a Tzolk'in date and a Haab' date was enough to identify a date to most people's satisfaction, as such a combination did not occur again for another 52 years, above general life expectancy.

Because the two calendars were based on 260 days and 365 days respectively, the whole cycle would repeat itself every 52 Haab' years exactly. This period was known as a Calendar Round. The end of the Calendar Round was a period of unrest and bad luck among the Maya, as they waited in expectation to see if the gods would grant them another cycle of 52 years.

Long Count

Since Calendar Round dates can only distinguish in 18,980 days, equivalent to around 52 solar years, the cycle repeats roughly once each lifetime, and thus, a more refined method of dating was needed if history was to be recorded accurately. To measure dates, therefore, over periods longer than 52 years, Mesoamericans devised the Long Count calendar.

The Maya name for a day was k'in. Twenty of these k'ins are known as a winal or uinal. Eighteen winals make one tun. Twenty tuns are known as a k'atun. Twenty k'atuns make a b'ak'tun.

The Long Count calendar identifies a date by counting the number of days from the Mayan creation date 4 Ahaw, 8 Kumk'u (August 11, 3114 BC in the proleptic Gregorian calendar or September 6 in the Julian calendar). But instead of using a base-10 (decimal) scheme like Western numbering, the Long Count days were tallied in a modified base-20 scheme. Thus 0.0.0.1.5 is equal to 25, and 0.0.0.2.0 is equal to 40. As the winal unit resets after only counting to 18, the Long Count consistently uses base-20 only if the tun is considered the primary unit of measurement, not the k'in; with the k'in and winal units being the number of days in the tun. The Long Count 0.0.1.0.0 represents 360 days, rather than the 400 in a purely base-20 (vigesimal) count.

Table of Long Count units

Days	Long Count period	Long Count period	Approx solar years
1	= 1 K'in
20	= 20 K'in	= 1 Winal	0.055
360	= 18 Winal	= 1 Tun	1
7,200	= 20 Tun	= 1 K'atun	19.7
144,000	= 20 K'atun	= 1 B'ak'tun	394.3

There are also four rarely used higher-order cycles: piktun, kalabtun, k'inchiltun, and alautun.

Since the Long Count dates are unambiguous, the Long Count was particularly well suited to use on monuments. The monumental inscriptions would not only include the 5 digits of the Long Count, but would also include the two tzolk'in characters followed by the two haab' characters.

Misinterpretation of the Mesoamerican Long Count calendar is the basis for a New Age belief that a cataclysm will take place on December 21, 2012. December 21, 2012 is simply the last day of the 13th b'ak'tun. But that is not the end of the Long Count because the 14th through 20th b'ak'tuns are still to come.

Sandra Noble, executive director of the Mesoamerican research organization FAMSI, notes that "for the ancient Maya, it was a huge celebration to make it to the end of a whole cycle". She considers the portrayal of December 2012 as a doomsday or cosmic-shift event to be "a complete fabrication and a chance for a lot of people to cash in." The 2009 science fiction apocalyptic disaster film 2012 is based on this belief.

Supplementary series

Many classic period inscriptions include a supplementary series. The supplementary series was deciphered by John E. Teeple (1874–1931). A supplementary series consists of the following:

Nine lords of the night

Each night was ruled by one of the nine lords of the underworld. This nine day cycle was usually written as two glyphs: a glyph that referred to the Nine Lords as a group, followed by a glyph for the lord that would rule the next night.

Lunar series

A lunar Series generally is written as five glyphs that provide information about the current lunation, the number of the lunation in a series of six, the current ruling lunar deity and the length of the current lunation.

Moon age

The maya counted the number of days in the current lunation. They started with zero on the first night that they saw the thin crescent moon.

Lunation number and lunar deity

The Maya counted the lunation in a cycle of six, numbered zero through 5. Each one was ruled by one of the six Lunar Deities. This was written as two glyphs: a glyph for the completed lunation in the lunar count with a coefficient of 0 through 5 and a glyph for one of the six lunar deities that ruled the current lunation. Teeple found that Quirigua Stela E (9.17.0.0.0) is lunar deity 2 and that most other inscriptions use this same moon number. It's an interesting date because it was a Ka'tun completion and a solar eclipse was visible in the Maya area two days later on the first unlucky day of Wayeb'.

Lunation length

The length of the lunar month is 29.53059 days so if you count the number of days in a lunation it will be either 29 or 30 days. The maya wrote whether the lunar month was 29 or 30 days as two glyphs: a glyph for lunation length followed by either a glyph made up of a moon glyph over a bundle with a suffix of 19 for a 29 day lunation or a moon glyph with a suffix of 10 for a 30 day lunation.

Venus cycle

Another important calendar for the Maya was the Venus cycle. The Maya were skilled astronomers, and could calculate the Venus cycle with extreme accuracy. There are six pages in the Dresden Codex (one of the Maya codices) devoted to the accurate calculation of the heliacal rising of Venus. The Maya were able to achieve such accuracy by careful observation over many years. There are various theories as to why Venus cycle was especially important for the Maya, including the belief that it was associated with war and used it to divine good times (called electional astrology) for coronations and war. Maya rulers planned for wars to begin when Venus rose.