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Astronomy of the Mayans
The Importance of Astronomy
in Mayan Society
In the Mesoamerican culture, the practice of
astronomy was extremely important. To the Maya of Mesoamerica, this ancient
science reflected order in the universe and the gods' place in it. This order
reflected an inherent harmony present in their general theological view of the
universe. To the Mayans, capturing the essence of time was of the utmost importance.
In their cosmology, space and time were inevitably intertwined, as is evidenced
by their complex calendar system that combines spatial attributes of the universe,
such as animals and plants, with temporal movements of astronomical objects.
Although the Mayans never invented water clocks or other specific time-keeping
devices, they used the sky as a method of measuring the passage of time.
The Mayans believed that celestial events were
indicative of communication with the gods. Specific astronomical objects represented
certain deities, whose divine lives were portrayed in the daily, monthly, and
yearly changes in their appearance. The religious aspect of astronomy was also
taken one step further: to astrology. The movement of constellations and other
objects across the sky represented a connection between celestial events and
human affairs. In other words, the practice of astronomy- in the form of astrology-
was believed to have an influence on every Mayan. |
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| Finally, probably one of the most tangible and
practical benefits of astronomy was on agriculture. The appearance of certain
constellations or planets in the sky heralded the planting season. The more
they understood the sky, the more assurance there was that the people would
not starve. It can be argued on this basis alone that astronomy was a practice
which promoted the success of the Mayan civilization. |
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The Mayan Priest-Astronomers
The Mayan practice of astronomy was relegated
to the ilhuica tlamatilizmatini, or "wise man who studies heaven". These
priest-astronomers had a great amount of power, given the fact that they could
essentially 'predict' the future. Their knowledge of the patterns of the sky,
and of the mathematics that solves more complex patterns, led them to an exalted
position in Mayan society. The figure below shows an astronomer with his eye
stretched out to the heavens. Priest-astronomers spent the dark hours determining
the time of night. Of course, the length of the days varies substantially from
season to season, and therefore the astronomers had to be very knowledgeable
about the sky in order to know the hour and to predict when the sun would rise
again. |
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The Mayan astronomers officially began the day
at sunrise, although for some Mayans the day began at either noontime, when
the sun was at its highest point, or at sunset. Starting the day at these times
may seem strange to those of us conditioned to a western view of time. However,
our own time is relatively unusual: we start the day when the sun is almost
at its anti-zenith, when it is at its highest point on exactly the other side
of the Earth!
The priest-astronomers recorded Mayan cosmology
in codices, many of which were burned by the Spanish. A few codices remain,
and several Spanish historians also recorded basic Mayan cosmology. Codex Vaticanus
A is a wealthy source of information on how Mayans viewed the universe. In this
document, as in the figure below, it is portrayed as a multi-layered universe
consisting of thirteen levels of the heavens and nine layers of the underworld,
with the Earth sandwiched in between and belonging to both.
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Mayan Cosmology
Michael Coe gives a wonderful explanation of
Mayan cosmology in his article on Mesoamerican astronomy (see references).
In the center of the universe, the Earth is layer one of the upper world and
the underworld. It is conceptualized as a large wheel surrounded by the teoatl,
or divine water, which is an ocean that extends to the horizon. The second layer,
called Ilhuicatl metzli, is where the moon and clouds reside. The fixed
stars lie in the next layer, known as Citlalco, where the deity Citlallicue ("She of the Starry Skirts") lives. The sun, also known as Ilhuicatl Tonatiuh,
occupies the fourth layer, while Venus, the "Great Star," inhabits the fifth.
Layer six is called Ilhuicatl Mamalhuazocan, or "Heaven of the Fire Drill,"
which represents an unidentified constellation (perhaps Orion's Belt). This
layer is also where comets ("Stars that Smoke") come from, and where the fire
serpents attend to their duty of bringing the sun from the east to the zenith.
The seventh layer is the black or green heaven, fierce with winds or storms,
and the eighth layer is blue heaven, which is where dust lies. The next layer,
the home of thunder, is called Itztapal Nanatzcayan, or "Where Stone
Slabs Crash Together." Layers ten, eleven, and twelve represent respectively
the colors white, yellow, and red. Finally, the last layer, called Omeyocan,
is where the dual male-female god, who created space and time, lives.
The nine-layered underworld also played a significant
part in Maya cosmology. The Milky Way was seen as a road of souls traveling
to the underworld, or as the umbilical cord connecting heaven and the underworld
to the Earth. As Michael Coe so eloquently states, "The Mesoamerican cosmos
was one in constant flux, in which space and time were co-terminous, in which
the heavenly bodies moved in fixed layers, and which was in constant peril of
cataclysm". |
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Mayan Astronomy
Although the Maya appreciated the sky as a whole
and its infinite dimensions, they were particularly interested in certain specific
astronomical objects. The sun, the moon, Venus, and specific star clusters and
constellations were most important. These objects were given the most attention
by the priest-astronomers, who spent generations finding the precise paths of
these objects across the sky and through the seasons.
The most important object in the sky is the
sun, which is universally recognized as the prime life-giver on Earth. Tonatiuh,
a red eagle with a large and all-seeing eye, was the god associated with the
sun. Because of the tilt of the Earth's axis, the sun appears at different positions
in the sky depending on the time of year. This tilt is what produces the seasons
experienced on Earth. The Maya accurately calculated times when the sun would
rise and set, and even more amazing, they determined the length of the solar
year to be 365 days. A tropical year is actually 365.2422 days long, so they
were very close in their calculations. Unfortunately, even this small error
means that the calendar which they created based on their solar year calculations
would be off by approximately one month every 100 years, or by almost a whole
six months every 600 years. This is obviously a dramatic difference, but there
is evidence that the priest-astronomers continually updated their records and
predictions so that the calendar remained accurate throughout the generations.
The moon was another object of interest to the
Mayans. It was represented by a female deity who had powerful influence on terrestrial
events. A waxing moon had the attributes of the beautiful, ideal woman, while
a waning moon was considered to be an old female deity who ruled over childbirth.
Around 300 C.E., the Mayans began to keep track of synodic lunations, or the
interval between successive full moons. A Mayan astronomer calculated that there
were exactly 149 moons over a period of 4400 days, which works out to an average
lunation of 29.53 days. In the city of Palenque, it was found that there are
405 moons in 11,960 days, which means that an average lunation is 29.53086 days.
This is remarkable accuracy, given that the actual average lunation is 29.53059
days.
Venus held a particular attraction for the Mayans.
It was considered to be connected with the major deity Quetzalcoatl. It was
called Xux Ek, the "Great Star," and the Mayans knew that it is the same object
that appears in both the morning and the evening at different times of the year.
The priest-astronomers determined the synodic period of Venus (how long it takes
to orbit the sun) to be 584 days, which is again incredibly close to the actual
period of 583.92 days. When Venus rose in the mornings, it was considered bad
luck, and everyone would stay inside their homes and block their chimneys so
that the evil light from Venus could not enter. The Mayans also calculated the
synodic periods of Mars as 780 days (actual = 779.936 days) and Mercury as 117
days (actual = 116 days), but they seemed uninterested in Jupiter and Saturn,
the other bright planets. None of the planets were actually seen as objects
different from the rest of the stars, which is unusual considering that they
move significantly in relation to the fixed stars. |
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Certain star clusters and constellations also
held special meaning for the Maya. For instance, the Pleiades star cluster appears
in the morning sky around planting time, in late April. This meant that the
Maya could plan ahead for the planting season, since they could predict the
rising of the Pleiades in connection to the appearance of other constellations
on the horizon. The Pleiades was called tianquiztli, which meant "marketplace".
There is evidence that the Mayans thought of the Pleiades as being the center
of the layer of fixed stars, rather than Polaris, around which the rest of the
sky seemingly revolves. The builders of the ancient city of Teotihuacan, below,
aligned their main street to the Pleiades. Polaris, or Xaman Ek, was,
however, used by travelers to orient themselves on land. |
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| The sky closer to the equator is the most vivid
on Earth. Due to the fact that the Earth is a sphere, at a point on the equator
people have the opportunity to view all of the constellations visible throughout
the world, exactly twice the number visible at either of the poles. Constellations
such as the Big Dipper, Orion's Belt, Cassiopeia, and the Southern Cross were
also important to the Maya, although of course they were viewed differently
than our western tradition teaches. Festivals were held when the Pleiades and
Orion's Belt rose at sundown and vanished at dawn. Constellations are shown
on the border of the Aztec calendar stone, shown below. More captivating objects
such as comets were believed to be an even more direct link to the human world.
If a comet, or "star that smokes," appeared in the sky, it foretold the death
of a noble person. Often, correlations were made between celestial and terrestrial
events, which led to a permanent linkage between humans and gods. |
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| General predictions concerning the placement
of astronomical objects in the sky at a certain time were not necessarily difficult
to make, considering that there was an entire crew of priest-astronomers who
had the sky entirely memorized. However, it is a completely different story
to make accurate and specific predictions about certain astronomical events.
We have already seen how the Maya determined synodic periods of several objects
with amazing accuracy. On the whole, these calculations were simply done by
counting, for instance, the number of lunar revolutions in a certain time period.
For more complex calculations, however, mathematics was invented. |
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| A prime example of the usefulness of mathematics
is in the science of predicting eclipses. Solar eclipses, known as chi' ibal
kin, or "to eat the sun," were a particular cause for distress among the
Maya people. Eclipses can be terrifying events for those who do not understand
the basic reasoning behind the occurrence, and so being prepared for them was
important. Predicting eclipses is a considerably more complicated task than
determining when the sun would rise or set, because it involved correlating
the synodic lunations with the solar calendar. In other words, the movement
of the Earth, the sun, and the moon all had to be taken into account, which
is no small feat for anyone to accomplish. Since the orbital plane of the moon
is inclined by 5 degrees to the plane of the Earth's orbit, eclipses do not
happen at every full and new moon. Instead, they occur only when the moon happens
to be in the ecliptic plane at the same time that it is at the correct position
in line with the sun and Earth. |
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| Maya priest-astronomers determined the nodes
when the paths of the moon and sun cross, which is every 173.31 days. During
this time, eclipses may occur within 18 days of the node. One example of an
eclipse table resides in the Dresden Codex, which was written in the eleventh
century in the northern Yucatan. The codex is made of ficus tree bark, and the
pages are covered with lime for a glossy finish. The glyphs are painted in red
and black with a very fine brush. In the eclipse section of the Dresden Codex,
two numbers appear quite frequently. The numbers 177, which is approximately
the length of six lunations, and 148, or five lunations, are representative
of times when eclipses were predicted. The astronomers periodically corrected
the eclipse tables, learning from their small mistakes and adjusting the calendars,
and so on several occasions we see that the number 178 appears in place of 177.
In effect, the eclipse tables consist of columns and rows of the numbers explained
above, and in some cases, the eclipse glyph is presented instead. This symbolizes
days when an eclipse could be expected, and if one did occur, the number was
replaced by the eclipse glyph. |
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Mayan Mathematics
The Maya mathematical system on which all this
was based was incredibly advanced, and it was developed starting about 500 B.C.E.
During the period of the Dark Ages in Europe, the Mayan system was more refined
than any in the world at that time. They used a vigesimal, or base 20, number
system, which seems foreign to us but is actually quite easy to use with practice.
Mayan numbers consist of a series of dots and bars, where dots have a value
of one and bars represent five. The numbers one through nineteen, and a series
of glyphs representing the number zero, are shown in the picture below. |
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| Our base 10 number system uses a decimal system
based on powers of ten, i.e. 1; 10; 100; 1000; and so on. The Mayan system operated
on exactly the same principles, except that the 'decimals' were based on powers
of twenty, i.e. 1; 20; 400; 8000; 160000. An example of simple addition of a
large number is shown in the figure below . The Maya also developed the concept
of zero, which had immense benefit as a place-holder and vastly simplified basic
arithmetic, along with making it possible to do more complex calculations. |
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The Mayan Calendar
Perhaps the most important application of the
Mayan mathematical system was in the development of their calendars. The Mayans
were obsessed with numerology, and used many "special numbers" to create their
two interconnected calendars. The ritual calendar consisted of thirteen 20-day
periods, which totaled 260 days. Although it is unclear exactly why the Maya
chose a 260-day calendar, there are several theories. First, the numbers 13
and 20 were two of the numbers considered to have magical powers. Second, by
coincidence, two ritual calendar years (520 days) is the same as 3 eclipse half-years
(520 days). Finally, although this is a controversial idea, 260 days is approximately
the length of human gestation (266 days). It seems likely that a combination
of these factors influenced the creation of the 260-day ritual calendar. Each
day in a 20-month period of the ritual calendar is represented by a specific
animal, plant, or natural force.
The Maya also developed a solar calendar, detailing
the so-called Vague year. It was 365 days long, consisting of eighteen 20-day
periods plus a final five "days without name," which were considered unlucky.
Certain groupings of years held special meaning. For instance, the 52 Vague
year cycle represented the time when both the ritual and the Vague calendars
would again correlate to the same starting day. In addition, the 52 years were
broken down into four 13-year periods, each being thought of as a specific cardinal
direction.
In addition to this connection between the calendars,
there are several other mathematical coincidences that had great importance.
There are exactly 146 ritual years in 65 synodic periods of Venus, and similarly
eight Vague years are equal to five synodic periods of Venus . The Maya used
their knowledge of the sky and their mathematical prowess in a symbiotic relationship,
where astronomical cycles precipitated the use of numbers and vice-versa. |
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Alignment of Mayan Buildings
and Temples
It has been recognized by archaeologists that
many buildings and temples in Mayan cities have astronomical orientations. This
is a field in which there is much on-going work, particularly by Anthony Aveni
and his colleagues (see references). Aveni states
that "while most Mesoamerican cities exhibit a planned appearance, frequently
one or more buildings at a given site seem out of line relative to neighboring
structures…One possibility is that astronomical events occurring on or near
the horizon could have determined the way a building would face". |
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| A prime example of astronomical orientation
is the so-called Building J at Monte Alban, which was built around 275 B.C.E.
This building was constructed in an arrow shape, and Aveni found that five of
the brightest stars in the sky would at that time have set approximately at
the point of the arrow. In addition, a line drawn perpendicular to the front
steps of the building would have pointed directly to the place on the horizon
at which the bright star Capella rose. By coincidence, it seems that the appearance
of Capella at this position could have heralded the passage of the sun through
the zenith (the point directly overhead), since at Monte Alban these events
are almost simultaneous. Evidence of this appears in the presence of a zenith
tube at the same site, which points directly overhead and effectively finds
the sun's zenith passage. An example of a zenith tube, this one from the city
of Xochicalco, is shown in the figure below. |
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Mayan cities all show signs of astronomical
orientation in the construction of buildings. Many of these were actually observatories
that had special viewing windows set into the walls. Each window corresponded
to a celestial event, for instance the rising of the star Sirius or the setting
of the Pleiades. Buildings were purposefully aligned with bright stars like
Capella and Sirius, or with Venus, or with the position of the sun's transit.
This diagram of Uxmal shows the astronomical placement of buildings as determined
by Anthony Aveni. |
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| The fact that the construction of Maya cities
depended on astronomy is proof of the intense relationship that Maya had with
the sky. The priest-astronomers' power was indicative of the essence of their
duties: if someone can foretell the actions of astronomical objects which are
linked to gods, then in the Mayan frame of reference that person is in communication
with the deities. Astronomy therefore characterizes many facets of Mayan life,
including religious aspects such as connecting the gods' actions to humans'
lives and practical aspects like measuring time and preparing for planting season.
Primarily, though, the Mayan practice of astronomy was actually astrology. The
dynamic universe was viewed as the infinite home of the gods, and the work of
the men who studied this universe brings a unique perspective to our modern
science of astronomy. |
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REFERENCES FOR THIS PAGE:
Anthony Aveni. Ancient Astronomers.
Smithsonian Books, 1993.
Anthony Aveni. "Astronomy
in Ancient Mesoamerica." In In Search of Ancient Astronomies, edited by E.C.
Krupp. Doubleday and Company, 1977. 165-202.
Anthony Aveni. "Possible Astronomical
Orientations in Ancient Mesoamerica." In Archaeoastronomy in Pre-Columbian America,
edited by Anthony Aveni. U. of Texas Press, 1975. 163-190.
Anthony Aveni. Skywatchers
of Ancient Mexico. U. of Texas Press, 1980.
Michael Coe. "Native Astronomy
in Mesoamerica." In Archaeoastronomy in Pre-Columbian America, edited by Anthony
Aveni. U. of Texas Press 1975. 3-31.
Evan Hadingham. Early Man
and the Cosmos. Walker and Company, 1984.
Guillermo Hinojosa. Personal
interview. April 25, 2000.
E.C. Krupp, Echoes of the
Ancient Skies: The Astronomy of Lost Civilizations. Harper and Row, 1983.
The Maya Astronomy Page. http://www.michielb.nl/maya/.
Colin A. Ronan. Changing Views
of the Universe. MacMillan, 1961.
Clive Ruggles. Mesoamerican
Images. http://www.le.ac.uk/archaeology/rug/image_collection/hier/am/r2.html.
Clive Ruggles. Peruvian Images. http://www.le.ac.uk/archaeology/rug/image_collection/hier/am/r3.html. |
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