Ancient civilizations and communities worldwide wondered about the mysteries of the skies, leading to existential reflections and observations that influenced peoples understanding of how the world was created and how society works. Today, researchers have identified ways in which celestial patterns helped ancient societies understand how landscapes change through time. Pre-Columbian civilizations recorded their observations through architecture, building temples to commemorate astral events and serve as observatories or calendric systems for measuring time.What Is Archaeoastronomy?A photograph of a comet from Stonehenge by James Rushforth, 2020. Source: BBC Sky at Night MagazineArcheoastronomy is a field of study that originated as a combination of archaeology and astronomy. However, more recent approaches to archeoastronomy propose it as an interdisciplinary field investigating how ancient communities and civilizations developed sky observation, measurement, and orientation technologies, sometimes accompanied by ritualistic practices and religious beliefs commemorating astral events. Although the discipline originated mainly as speculative fiction, today it has been able to integrate scientific methods, granting it more validity in the scientific community.More straightforwardly, archeoastronomy studies how ancient cultures assigned cultural significance to the movements of the stars, planets, moon, and sun. It also pursues the study of temples and stone-made observatories that helped ancient peoples identify seasons for cultivation or record historical dates related to important social events. The prototypical example of archaeoastronomy is the study of Stonehenge in England, where stones arranged in a circle mark a ceremonial site with a processional path that aligns with the orientation of the rising sun in midsummer and the sunset in midwinter. This alignment of structures with astral objects has caught the disciplines attention since the 20th century.Why Was Astronomy Important for Ancient Civilizations?Photo of Piedra del Sol (Sun Stone) depicting a calendar, N.D. Source: Instituto Nacional de Antropologia e Historia, MexicoObserving the skies and understanding how patterns of astral movement relate to the surrounding environment has been one of the primary sources of cosmological understanding, mythological stories, and ritualistic practices among various cultures in the past and today. Christopher Y. Tilley dubbed this interest the phenomenology of landscape, a perspective that reveals how prehistoric sites related to the specificities of different topographic settings are material evidence of communities deep and heightened landscape perception.Understanding the sky led to the creation of sophisticated calendars and orientation tools, as well as mythical stories that explained the worlds origin and how society should work. This was especially important for agrarian societies because it allowed them to better understand natural cycles of climate phenomena and soil fertility, influenced by rain as well as the direction and intensity of sunlight. At the time, what was observed was often explained as a combination of natural phenomena and mythical stories that sought practical ways to understand and gain some control over the environment. In most cases, the movements of celestial objects were believed to be caused by divine entities, which made the sky an essential part of many peoples religious beliefs as it was conceived as a space where divine entities resided and that held power over their bodies and territories.The Maya of the Yucatn PeninsulaPhoto of the Mayan city of Chichen Itza by Paul Nicklen, 2013. Source: National GeographicBetween the 3rd and 9th centuries BCE, the Mayan civilization reached its golden age in the Yucatn Peninsula in present-day Mexico, Belize, Guatemala, and Honduras. The Maya believed the sky was populated by different divine entities corresponding to different environmental observable phenomena, such as rain, storms, or astral movements, especially those related to the sun, moon, and Venus.Their interest in the sky was mainly due to their need to predict seasons and understand their influence on human behavior and social life. Their sophisticated observations were registered in the Mayan codices, later uncovered by the first European conquistadors in the 16th century. Some inscriptions showed different numbers related to dates of important social and historical events. Initially, it was believed that Maya only registered these dates with respect to the passage of time. However, it was later discovered that the inscriptions were often highly precise registers of historical dates. This led archaeologists to suggest they had a deep understanding of both time and space, likely due to systematic sky observation.In addition to the written record, Mayans developed tables to register and predict eclipses. They created famous Mayan calendars, such as the Tzolkin, the Haab, and a long-count calendar. Because calendric and astronomical events were highly important in Mayan society, astronomers played a relevant role in their social hierarchy. They were involved in architectonic construction and urban planning. Moreover, Mayans built temples that aligned with different astral movements. For instance, in the city of Uxmal, different building orientations are related to the movements of Venus, an entity also represented in different carved faades.Page 34 of Tro-Cortesianus Codex, or Madrid Codex, showing on top what is believed to be a depiction of a Mayan astronomer, 900-1251 BCE. Source: Foundation for the Advancement of Mesoamerican Studies, Inc FAMSIPerhaps the most remarkable example of Mayan archaeoastronomical construction is the temple of Chichen Itza in the Yucatn Peninsula. The site was registered in the UNESCO World Heritage List in 1988, includes temples built between 800 and 1100 BCE, and was visited by over 2 million people in 2023.Photo of Temple of Kukulcn during the spring equinox, N.D. Source: Naatik MexicoAmong the different temples that can be found in the area, the principal one is the Temple of Kukulcan, or El Castillo (The Castle). This pyramid-like construction has four sides, each with a staircase that connects the base with a dual-entrance square temple at the top of the building. Kukulcan, in Mayan Kuukul Kaan, is the name of a mythical feathered serpent related to forces of wind and water, believed to have similarities with the Aztec deity Quetzalcoatl.The staircases have carved stone serpent heads at their base, which are the protagonists of one of the most spectacular archaeoastronomical events in the world. Every year, on the 21st of March, during the spring equinox, the setting suns light hits one of the pyramids corners, creating a wave-like shadow on the staircase balustrade. As the sun sets, the play of light and shadow creates the illusion that a serpent is descending from the top of the temple to its base.The Inca of TawantinsuyuPhoto of Intihuatana stone in Machu Picchu believed to be used for astronomical observations, N.D. Source: Machu Picchu CenterThe Incas were the most extensive civilization in the Americas. After the arrival of Spanish conquistadors in the 16th century under the direction of Francisco Pizarro, the empire faced a rapid decline due not only to the invasion but also to internal political instability and diseases imported from Europe. The Incas had a rigid and complex sociopolitical hierarchy that concentrated power in the city of Cusco, which still exists today in Peru.In contrast with the Mayan codices, the Incas used quipus to write and count, a system consisting of ropes and knots. Some of their most impressive architectural creations were stone-built houses and temples featuring perfectly carved stones assembled in exact alignment with one another and an extensive network of roads that connected their Empire and that are still used today.Astronomical observations among the Incas were likely to have been registered using quipus, as some depictions of astronomers in historical chronicles have suggested. Evidence that the Incas had deep astronomical knowledge also lies in pillars dedicated to the Sun that were erected in different zones of Cusco. One particularly remarkable Inca astronomical site is the Intihuatana found in Machu Picchu, a ritual carved stone that is believed to have been used as a clock and calendar and aligned with the sun during the winter solstice. This lithic clock was discovered in 1911, and it is believed that the reason it still exists is simply because the Spanish never found it.Other monoliths were subject to severe destruction and looting during the Spanish conquest of the region, as they likely believed these sites were an affront to Christianity. Some recent studies have shown that other regional sites may have served astronomical purposes, such as the Island of the Sun in Titicaca Lake, the Urubamba Valley, and Chankillo.The Muysca of ColombiaPhoto of Templo del Sol by Aizquier, 2007. Source: Wikimedia CommonsStudying archaeological sites and their relationship with astronomical observations is a relatively new field in Colombia. Due to the intensive looting and destruction of indigenous sites by Spanish conquistadors in the 16th century, many astronomical sites disappeared. This was influenced by Christian evangelizers, who thought they were the work of the devil and a threat to building civilization. The aggressive sociocultural replacement of Indigenous society by Spains societal rules destroyed much of the local indigenous knowledge, and deep astronomical understandings reflected in sacred buildings and temples were lost.However, some ethnohistorical research done among indigenous communities of Colombia, such as the UWA, Kogui, Tukano, and Muysca, showed how these communities may have achieved sophisticated knowledge of the sky, which they conceived of as a map. Muyscas built astronomically oriented temples based on divisions between the sun and moon, which also served to measure time. These structures reflected space, natural cycles, and philosophy.Muyscas also developed a calendric system that they represented as a circle, a shape used to build houses and temples. One example is the Templo del Sol (Suns Temple), which is still preserved in the form of an artificial replica in the region of Boyac, near Bogot. The original construction was looted and destroyed by two soldiers under the direction of Gonzalo Jimnez de Quesada, a Spanish conquistador of the Nuevo Reino de Granada (New Kingdom of Granada, now Colombia). This construction was dedicated to the Sun God Xue. It was built in alignment with the four cardinal directions, each marked by a door and upper squared openings that allow sunlight to reach the temples central pillar on December 22 every year. Another important site is located near the area, El Infiernito (the little hell), where different vertically standing monoliths are organized on a line, suggesting they could have been used as an astronomical observatory.The Americas Lost Astronomical KnowledgeIllustration of the Piedra del Sol Azteca (Aztec Sun Stone) depicted by Antonio de Leon y Gama in 1792. Source: Wikimedia CommonsThe rapid dismantling that indigenous communities experienced during the conquest of the Americas resulted in much of their astronomical knowledge being destroyed. The Spanish Empire wanted to expand its rule throughout the Americas and civilize local communities. The Catholic religion played a big role in advocating the destruction of any local representation of what were considered diabolic symbols. For instance, sacred Indigenous sites were replaced by churches to facilitate evangelization.Despite this, archeoastronomy has played an essential role in the study of ancient American civilizations. It reveals that Indigenous cosmogonies were more than mythical stories; they were the product of advanced sky observation and measurement technologies that allowed communities to understand what was happening in the sky and how it could influence their lands and societies.Bibliography:Magli, G. (2020). Archaeoastronomy: introduction to the science of stars and stones. Springer Nature.Schele, L., Freidel, D., & Parker, J (1995). Maya Cosmos Quill, New York.ReichelDolmatoff, G. (1982). Astronomical models of social behavior among some Indians of Colombia. Annals of the New York Academy of Sciences, 385(1), 165-181.Tilley, C. Y. (1994). A phenomenology of landscape: places, paths, and monuments (Vol. 10). Oxfor