El Caracol, Ancient Maya Observatory at Chichén Itzá

 

 

El Caracol, Ancient Maya Observatory at Chichén Itzá by Vicky L. Oldham, April 18, 2022

Chichén Itzá, the ancient Maya ceremonial site on the Yucatan Peninsula, Mexico, features some of the most incredible stone monuments in the world.  Among its buildings that rose above the jungle canopy, one served as a naked-eye astronomical observatory designed to follow the cycles of the planet Venus and other celestial objects (Fraknoi, 2016).  Aptly named "El Caracol" or "the snail" in Spanish, its name refers to the winding spiral staircase leading to a tower in its interior with 360-degree views of the heavens. 

Figure 1. El Caracol at Chichén Itzá

Note: Chichén Itzá – Caracol by Yamen, 2020.  Entrance view of the partially restored ancient Maya astronomical observatory. Wikimedia Commons. (https://commons.wikimedia.org/wiki/File:Chichen_Itza_-_Caracol_030120020_008.jpg). CC BY-SA 4.0.

Part of El Caracol's upper structure collapsed after many centuries of abandonment.  Fortunately, the top was still accessible, leading to long, narrow window shafts enabling observers to focus on key celestial events (Exploratorium, n.d.).  El Caracol has been compared to a "stone wedding cake" (The Yucatan Times, 2020, para. 2).  The building's bottom platform measures 246 by 226 feet and leads to a smaller, offset upper terrace.  The top terrace supports three nested cylindrical towers to form the observatory.  At first, it looked uncannily like a modern observatory to archaeologists, with imagined openings for a telescope (a device that the Maya lacked).  However, archaeologists did not confirm El Caracol's sole purpose as an observatory immediately (Aveni et al., 1975).  After extensive investigation, experts finally agreed on its purpose: to track celestial events like the movements of the Sun, Venus, and important stars.  According to archaeologist Anthony Aveni, noted for his achievements in archaeoastronomy (the study of astronomical knowledge of prehistoric cultures), "sightlines for 20 [celestial events] could be found in the structure" (Stockton, 1986).  Still, puzzling orientations at El Caracol and other Maya buildings confounded archaeologists as they found no known alignments.

Cycles of the Heavens = Order and Survival

The Maya's success as a civilization is directly linked to their careful observation of the sky over many centuries, making accurate predictions possible by studying the movements of celestial bodies.  Rather than comprehending their vast accumulation of data as a pursuit of science for its own sake, the Maya intended for astronomy to create order in their society.  The Earth, Sun and stars not only helped ancient people tell the time, but also the time of year, just by observing the sky and keeping records (CrashCourse, 2015, 00:07:18).  Accurate observations enabled agricultural planning, advanced mathematics, and helped the Maya develop the most sophisticated calendar system in the ancient world.   A recently found Maya calendar glyph has been dated to the third century BCE! (Dunham, 2022).  The discovery came as a complete surprise to archaeologists since it was previously thought that the Maya developed their calendar system in the first century BCE.

Figure 2. Diagram of El Caracol's Upper Platform and Tower with important celestial alignments

Note.  Diagram of El Caracol's Upper Platform and Tower with important celestial alignments.  Drawing by Vicky Oldham.  Data derived from Google Earth (2022), Star Gods of the Maya by Susan Milbraith (1999), and Stairways to the Stars by Anthony Aveni (1997).  

 

Figure 3.  Unreconstructed walls of the Caracol, Chichén Itzá 1930.

Note. Unreconstructed Walls of the Caracol, Chichén Itzá 1930, The Yucatan Times. (https://www.theyucatantimes.com/wp-content/uploads/2020/01/muros-del-Caracol-sin-reconstruir-Chichen-Itza-1930.jpg). Copyright 2020.

In addition to helping the Maya develop a precise calendar, sky watching influenced every cultural and ceremonial aspect of life, including the belief that their leaders communicated exclusively with their gods (reenacted in a short 3-D animation, El Mundo Maya) (ADV Estudio, 2020).  With their knowledge of time and ability to decipher alignments incorporated into their monuments, Maya rulers maintained their power, delivering accurate predictions critical to the survival of their subjects.

Table 1. Sampling of Astronomical Orientations at El Caracol, Chichén Itzá, Maya Archaeological Site. 

 

Note: Table data derived from Star Gods of the Maya by Susan Milbraith (1999), Stairways to the Stars by Anthony Aveni (1997), and The Caracol Tower at Chichén Itzá: An Ancient Astronomical Observatory? by Aveni, A. F., Gibbs, S. L., & Hartung, H., published in Science, 188(4192), (1975).

Understanding the Maya's dependence on regular cycles clarifies their reasons for extreme precision when establishing alignments, whether to mark the seasons, signal times for planting and harvesting, going to war, or paying homage to gods.  However, when archaeologists first began to study the orientation of Maya buildings, they found inconsistencies; despite the Maya's incredible display of architectural virtuosity, some buildings seemed to lack any purposeful placement.  Fortunately, some archaeologists still believed the Maya left nothing to chance, convinced they strategically planned the layout of their monuments using some hitherto unknown guide.

Mayan Buildings Wander Through Time

The locations of planets and stars vary slightly over time, their apparent movement in the sky dependent upon a wobbling motion of the Earth known as the "precession of the equinoxes."  Constellations seen in today's sky differ from constellations observed in antiquity.  An excellent example appears in the Farnese Atlas, a marble sculpture dating from the second century BCE holding a globe with constellations then visible.  But how does this affect the alignments at El Caracol?  During his measurement of the alignments at El Caracol, archaeologist Anthony Aveni checked the position of the Pleiades constellation as it would appear in 1000 CE.  He found it aligned perfectly to an El Caracol window shaft during a zenith passage of the Sun (Aveni et al., 1975).  Although positions of constellations appear to move slowly over millennia, offering some explanation for offset alignments in Maya monuments, it's not the only change to consider.  In Figure 2, the diagram of El Caracol shows a window for sighting "near" astronomical south—yet it is located west of true south. 

The late archaeologist Robert Fuson was among the first to propose a solution to the apparent inconsistencies in Mayan site alignments (Paredes, 2004).  He found that "the Maya shifted building alignments from time to time and often simultaneously at widely separated locations…indicating a moving reference point" (Fuson, 1969, para. 1).  Fuson followed this assertion with a compelling rationale: the Maya possessed the means to determine magnetic north and positioned their monuments accordingly.  This view became known as the "Fuson Hypothesis" (Klokocnik et al., 2007).  Although difficult to prove (due to the lack of magnetic declination data during the period of Maya building construction), archaeologists began to acknowledge its potential since it seemed to provide the best explanation for the unresolved orientations of some Maya structures.

It turns out that Earth's magnetic poles frequently change position and have done so continually throughout ancient times.  In contrast to the true polar alignments defined by the Earth's axis, the magnetic poles may drift from the geographical axis by great distances (Strzemieczny, 2019).  Using the "Historical Magnetic Declination" tool provided by NOAA (National Oceanic and Atmospheric Administration), we find that in the year 1590, the historic magnetic declination was seven degrees west of north in the Yucatan Peninsula (National Centers for Environmental Information, n.d.).  In 2021, the same general area returned a variance of one degree west of north.

According to a recent article in Smithsonian Magazine, Mesoamerican societies like the Olmecs, who predated the Maya, knew of, and used magnetic ores (Learn, 2019).  It is now speculated that Mesoamerican people devised rudimentary compasses from naturally magnetized minerals like hematite (often used for mirrors they hung around their necks) to determine the directions of magnetic poles (Fu et al., 2019).  The hypothesis is further supported by the idea that orientations of Maya buildings changed when they later built subsequent layers onto preexisting structures—suggesting they followed the Earth's meandering magnetic poles.

Conclusion

El Caracol is a fascinating ancient monument because it achieved a level of architectural excellence and dedication to a purpose hard to imagine for its time.  Designed from the start to study the heavens, it elevated the observer high above the jungle canopy to track the rising and setting of the Sun, its twice-annual zenith passages, and Venus' eight-year cycle against a backdrop of bright stars.  Through astronomy, the Maya shaped their entire worldview.  Observing celestial events enabled them to count time over short and extended stretches, affecting every facet of their lives.  Now, archaeologists have even more questions to explore as they consider the possibility that the Maya used a magnetic compass to plan and orient structures in their ceremonial centers, potentially making sense out of a long-confounding mystery.

 

 

References

ADV Estudio (2020, January 4). El Caracol, Chichén Itzá, Yucatán / ADV Estudio Arqueología Virtual [Video]. YouTube. https://youtu.be/uryHQaxDoXE

Aveni. (1997). Stairways to the stars: skywatching in three great ancient cultures. J. Wiley.

Aveni, A. F., Gibbs, S. L., & Hartung, H. (1975). The Caracol tower at Chichen Itza: An ancient astronomical observatory? Science, 188(4192), 977–985. http://www.jstor.org/stable/1740708

CrashCourse (2015, January 29). Cycles in the sky: Crash Course Astronomy #3 [Video]. YouTube. https://youtu.be/01QWC-rZcfE

Dunham, W. (2022, April 13). Earliest evidence of Maya calendar found inside Guatemalan pyramid. Reuters. https://www.reuters.com/lifestyle/science/earliest-evidence-maya-calendar-found-inside-guatemalan-pyramid-2022-04-13/

Exploratorium (n.d.). Ancient observatories: El caracol. Exploratorium. https://www.exploratorium.edu/ancientobs/chichen/HTML/caracol2.html

Fraknoi, A., Morrison, D., Wolff, S.C. (2016, October 13). Ancient astronomy. OpenStax. https://openstax.org/books/astronomy/pages/2-2-ancient-astronomy

Fuson, R.H. (1969). The orientation of Mayan ceremonial centers. Annals of the Association of American Geographers, 59(3), 494–512. https://doi.org/10.1111/j.1467-8306.1969.tb00687.x

Fu, R.R., Kirschvink, J.L., Carter, N., Mazariegos, O.C., Chigna, G., Gupta, G., & Grappone, M. (2019). Knowledge of magnetism in ancient Mesoamerica: Precision measurements of the potbelly sculptures from Monte Alto, Guatemala. Journal of Archaeological Science, 106, 29–36. https://doi.org/10.1016/j.jas.2019.03.001

Google Earth (2022). El Caracol, Chichen Itza. Google.com. https://earth.google.com/web/@20.6792575,-88.5708002,36.58951316a,206.77577736d,35y,0h,0t,0r

 Klokocnik, Kostelecky, J., & Vitek, F. (2007). Pyramids and ceremonial centers in Mesoamerica: Were they oriented using a magnetic compass? Studia Geophysica et Geodaetica, 51(4), 515–533. https://doi.org/10.1007/s11200-007-0030-7

Learn, J.R. (2019, August 6). Mesoamerican sculptures reveal early knowledge of magnetism. Smithsonian Magazine. https://www.smithsonianmag.com/science-nature/mesoamerican-sculptures-reveal-early-knowledge-magnetism-180972820/

Milbraith, S. (1999). Star gods of the Maya: astronomy in art, folklore, and calendars (1st ed.). University of Texas Press.

National Centers for Environmental Information (n.d.). Historic magnetic declination. NOAA. https://www.ncei.noaa.gov/maps/historical_declination/

Paredes, L. (2004, October 28). Robert Fuson, 77, longtime USF scholar. Tampa Bay Times. https://www.tampabay.com/archive/2004/10/28/robert-fuson-77-longtime-usf-scholar/

Stockton, W. (1986, March 25). Ancient astronomy points to new views of Mayan life. The New York Times. https://www.nytimes.com/1986/03/25/science/ancient-astronomy-points-to-new-views-of-mayan-life.html?sec=health&&n=Top/News/Science/Topics/Telescopes%20and%20Observatories&pagewanted=all

Strzemieczny, A.L. (2019, September 11). Our magnetic poles shifted in the past. Are we overdue for another shift, and how will that affect our electronics, the continents, and the Sun’s effect on us while the poles shift? Astronomy. https://astronomy.com/magazine/ask-astro/2019/09/our-magnetic-poles-shifted-in-the-past-are-we-overdue-for-another-shift-and-how-will-that-affect-our-electronics-the-continents-and-the-suns-effect-on-us-while-the-poles-shift

The Yucatan Times (2020, January 8). Unreconstructed walls of the Caracol, Chichen-Itza 1930 [Photo]. The Yucatan Times. https://www.theyucatantimes.com/wp-content/uploads/2020/01/muros-del-Caracol-sin-reconstruir-Chichen-Itza-1930.jpg

The Yucatan Times (2020, January 8). The Chichén Itzá series (4) "El Caracol". The Yucatan Times. https://www.theyucatantimes.com/2020/01/the-chichen-itza-series-4-el-caracol/

Yamen (2020, January 3). Chichen Itza - Caracol [Photo]. Wikimedia Commons. https://commons.wikimedia.org/wiki/File:Chichen_Itza_-_Caracol_030120020_008.jpg