Pre-Columbian Astronomy and Latin American

Of all the Pre-Columbian civilizations none has received as much attention both by scholars and the media as the ancient Maya. The reason is very simple: at its pinnacle, between 200 and 900 C.E., the classical Maya civilization created great art, sculpture, and architecture; they devised a complex religious pantheon; and they developed syllabic writing and numerical systems on a par with the West.

Maya.

Maya math was directed largely toward timekeeping (indeed the priest in charge of the calendar was—and still is—called the keeper of the day, ah kin). They counted their days in a base-20 system. Like the Babylonians (who used a different base) they dealt with time uniquely, by changing the scheme so as to identify the third position with 360 (18 20 rather than 20 20). Here was a way of handily reckoning the approximate length of the year. By the beginning of the Christian era they were writing inscriptions in "long count" that reckoned the number of days lapsed since the most recent cycle of creation. Maya mathematicians fixed the great event, which we would transcribe as 0.0.0.0.0 on their temporal odometer, to a date that corresponds in the Christian calendar to 12 August 3114 B.C.E. Though the reasons why they did so remain elusive, this deep-time setting of the commencement of creation is relatively common in highly stratified societies. But Maya time was enmeshed with other cycles that suggest a belief in a sensate universe, with all of its components interconnected—a universe that did not operate apart from human concern.

A shorter cycle, called the tzol kin (count of days), which the Maya still employ in the early 2000s, predated the long count by several centuries. Widespread throughout Mesoamerica yet unknown in the Old World, this 260-day round consisted of a series of twenty day-names preceded by numerical coefficients ranging from one to thirteen. Thirteen was the number of layers of heaven in Maya cosmology, while the bodily origin of twenty already is obvious. But other reasons may underlie the popularity of the number 260. In contemporary Guatemala, there is evidence linking this basic time cycle to the human gestation period. This convenient round number approximates nine lunar months (265.77 days) in the same way that 360 approximates the length of the seasonal year (365.2422 days). The tzol kin is also a close approximation to the mean interval of appearance of Venus as evening or morning star, and it beats harmoniously in the ratio of 2:3 with the eclipse reckoning period of 173.32 days. Such approximations offer the advantage to the calendar keeper of assigning particular sets of dates in the tzol kin to eclipse or Venus warnings.

Astronomers, along with the mathematicians and scribes who worked with them during the Classic period (c. 200–900 C.E.), were members of a courtly class. Excavations of an eighth-century elite burial at the Maya ruins of Copán, Honduras, revealed the remains of a scribe, his paint pot and brushes still intact. These specialists were required to know with meticulous accuracy every celestial cycle that might conceivably guide human destiny. Control over these time periods by the Maya lords, their superiors, enabled them to appropriately schedule their own affairs as well as those of the state. As in China, such court professionals advised the ruler about the proper time to make decisions. When should they enter into armed conflict, set a date for a royal marriage, or an ascent to the throne? When ought they to conduct a ritual, or make an offering to pay the debt to the gods for their assistance in producing a good crop or a healthy newborn child? One can imagine royal appointees going from town to town, their codices filled with detailed planetary calculations and agricultural almanacs tucked under their arms, ready and willing to advise the local rulers on such issues. Likewise can be imagined their subordinates advising commoners in the marketplace.

Inscriptions on carved monuments (stelae) at the Maya ruins of Copán, Yaxchilán, Palenque, and elsewhere connect seminal events in the lives of the rulers with key sky events such as eclipses and planetary conjunctions. These suggest that the ruler may have achieved cosmic status, there being an implied descent of royalty from ancestor deities who resided in the sky. Outdoor rites held in the open spaces that front the temples served to legitimize heaven-ordained actions by the ruler. Cosmic hierophanies, the interplay of timed light and shadow to manifest the sacred, were likely staged in the architecture of Palenque and Yaxchilán. The shadow of a descending serpent on Chichén Itzá's largest pyramid is still witnessed today on the spring equinox.

There exists little evidence regarding Mesoamerican observational technology. Pictographs from Central Mexican codices depict men peering over what could be sighting devices that consist of pairs of crossed sticks. Often these characters are portrayed in the recesses of temples, which suggests that such edifices might have been preferentially aligned toward events that took place at the local horizon. A few oddly skewed misshapen structures and buildings with narrow slots or windows do seem to align astronomically. For example, the cylindrically shaped Caracol of Chichén Itzá, Yucatan, possesses built-in sighting shafts oriented to key positions of Venus, the Mayan god representing the recycling of creation.

Aztecs.

At the time of European contact, the Aztecs controlled a vast empire centered on their capital of Tenochtítlan on the site of modern Mexico City. While their well-described practice of human sacrifice might tend to divert one's attention from pursuits so esoteric as astronomy, it must be remembered that the Aztecs offered the blood of their captives to the sun god Tonatiuh to keep the heavens in motion, lest eternal darkness befall them. Politically such a policy may be thought of as a mechanism of control and domination exerted by the Aztec rulers over their newly conquered tributaries all around the lake basin that surrounded their island capital. But from a religious perspective these sacrificial acts might be better regarded as mandatory rites of renewal of cyclic time in the life of the Aztec city paired with its dedication to cosmically sanctioned military conquest. The shape of Aztec time is also manifest in their documents. The Aztec historical record is rife with pictorialized events of nature, among them eclipses and smoking stars (comets and/or meteors). These books tell the reader that the sky is very much a part of civic life, for the pictures are juxtaposed alongside events of social importance, such as deaths, conquests, and accessions.

The Templo Mayor, largest of all Aztec buildings, exhibits a celestial alignment. One informant told a sixteenth-century Spanish friar that a certain festival took place at the temple when the equinox sun stood at its midpoint, but because it was a bit misaligned, Moctezuma needed to pull the temple down and straighten it. The temple's orientation is just what it would have had to be to permit the rising equinox sun to fall into the notch between the twin temples that once surmounted the flat-topped forty-meter-high pyramid. When the sun arrived there, Spanish chroniclers relate, a royal observer situated in the plaza fronting the bottom of the stairs carefully watched it. Like a town crier he would signal the time to begin the ritual of human sacrifice that attended that particular month of the year. The Aztec 52-year calendar round (the meshing of 260-and 365-day cycles) was cosmically timed as well. It began with the precise sighting of the Pleiades in the overhead position at midnight. When the time approached, one chronicler says, the priests ascended the Hill of the Star to affirm that the movements of the heavens had not ceased and that the end of the world was not imminent. Thus, one thinks of the sky as part of the background set for the effective performance of religious rites.

Inca.

The Inca, whose even larger empire thrived in the Andes while the Aztecs ruled much of Mesoamerica, embedded the sky in a unique scheme that united ideas about religion, social organization, and hydrology. The ceque system was conceived as a giant mnemonic map built into the capital city Cuzco's natural and artificial topography. Likely used elsewhere, the system is best known from descriptions by Spanish chroniclers, who state that ceques were imaginary radial lines grouped like spokes on a wheel, dividing the city into sections much like a pie graph. The wheel's hub was the Coricancha, the navel of the world and the temple of ancestor worship.

Each of the Cuzco's forty-one ceques was traced by a line of huacas, or sacred shrines, that extended outward along irrigation canals and natural water sources across the landscape. The Inca believed the 328 huacas to be openings in the mountain body of Pachamama, or Mother Earth, and there specific Xin groups left her offerings at specified times of the year. Some huacas were temples, others intricately carved rock formations, natural springs, and other landscape features. Still others were astronomical markers involved with the establishment of a calendar.

While not all investigators agree on the precise placement of astronomical huacas, it seems clear that they were part of a horizon-based solar calendar. In one instance, the northern-most pillar of a set of four on a hillside overlooking the capital served as a warning device. When the sun reached there the planting season in the Cuzco valley was approaching. People who cultivated crops at higher altitudes, where growth occurred at a slower pace, therefore would be allowed sufficient additional time to sow their seeds before planting commenced in lower levels of the valley. These dates were marked by the other pillars. The ceque system also indicated the various kin and ethnic groups that made up the population by designating certain huacas to their care. In this sense the order of worship of the ceques and their huacas constituted a mnemonic scheme that incorporated information, including astronomy, considered vital to the operation of the state.