Archaeoastronomy

Archaeoastronomy is the study of how people in the past understood the sky and used it in their lives. It looks at how ancient cultures saw stars, sunrises, moons, and other sky events, and how these events were important to them. Unlike modern astronomy, which uses science to study space, archaeoastronomy focuses on the meanings and symbols that different cultures gave to the sky.

This field combines many areas of study, such as archaeology, anthropology, and astronomy, to learn about the past. By looking at old buildings, art, and stories, scientists can discover how people long ago thought about the sky and its events. For example, they study how the Mayan astronomy connected the sky with farming and nature.

Archaeoastronomy can be studied in every culture and time period, even though the sky means different things to different people. It helps us understand how ancient beliefs about the sky shaped their world and how they saw the universe around them.

History

In the past, people have always been interested in the stars and how ancient structures might relate to them. Over time, the study of how ancient cultures understood the sky has grown from curious ideas to a respected area of research.

Early thinkers noticed that old buildings like Stonehenge seemed to line up with the sun or stars. In the 1900s, researchers like Alexander Thom and Gerald Hawkins suggested that places such as Stonehenge might have been used to track the seasons or predict special days. Some of their ideas were questioned, but they helped start serious study in this field.

Later, scientists began looking at how Native American cultures used the sky, using both old records and modern research methods. This led to many discussions among experts about the best ways to study ancient sky watching. Today, archaeoastronomy brings together many kinds of experts to understand not just whether ancient people watched the sky, but why it was so important to them.

Relations to other disciplines

Archaeoastronomy is a field that connects many different areas of study. It looks at how ancient people understood the sky and used what they saw there. It brings together ideas from archaeology, history, and anthropology. Some researchers study old buildings and landscapes to find clues about ancient sky watching. Others look at old writings or talk to people today to learn about past sky traditions.

People who study archaeoastronomy come from many backgrounds. Some are archaeologists, others are historians, and some are astronomers. They all ask different questions and use different ways to understand the past. Some focus on numbers and measurements, while others look more at the stories and meanings behind ancient sky traditions. This differences can sometimes cause debates, but it also helps us learn more about how people in the past saw the world around them.

Methodology

There is no single way to study archaeoastronomy. Researchers often depend on the kind of information available, such as the location of ancient sites or historic records. In some areas, like the Old World, there is less historic data, while in others, like the New World, researchers can use both site information and historic records.

One approach is called green archaeoastronomy. This method uses statistics to study ancient sites, especially where there is little social evidence. It looks at how ancient people may have used the sky for important dates. For example, some believe ancient people could predict special days by watching where the Sun set behind mountains. This method helps understand if ancient people had an interest in the sky, but it doesn’t always explain why they cared.

Another approach is brown archaeoastronomy. This method uses historic and cultural records to learn about ancient sky watching. For example, at Chichen Itza, researchers used records to understand what parts of the sky were important to the Mayans. They found that buildings sometimes lined up with special sky events, like the appearance of the planet Venus. This method can discover sky patterns that statistics alone might miss, but it can sometimes be less exact. Both methods are important for understanding how ancient people saw and used the sky.

Source materials

Archaeoastronomy looks at many ways people in the past watched the sky and used it. There are many sources that help us learn about these sky-related practices.

One common way to study this is by looking at alignments. This means checking if buildings or structures were built to point toward special places in the sky, like where the sun rises or sets. Some researchers study old writings to support this idea, while others look for patterns at many sites to show these alignments were not random.

Artifacts, such as special objects, can also give clues. For example, the Sky Disc of Nebra is thought to show the sky from a long time ago. By comparing it to other old objects and writings, researchers try to understand its meaning. Another example is the Antikythera mechanism, an ancient device that may have been used to track the movements of the stars and planets.

Art and writings on walls or stones can also help. Some writings even tell us how a place was used. For instance, a writing from Greece explains that a stone was put up to mark the winter solstice, when the sun is at its lowest point in the sky.

Ethnographies, which are reports from people who visited or studied other cultures, are also important. They can tell us about how people in the past thought about the sky. For example, some people in Mesoamerica believed that certain days when the sun was directly overhead were very important for farming. This knowledge helps us understand why some ancient buildings might be pointed in certain directions.

Ethnographies also help us avoid misinterpreting symbols. For example, some believe a drawing in Chaco Canyon shows a star event from the year 1054, but others think it means something else entirely. Studying how living cultures use similar symbols can help us understand these ancient marks better.

Recreating the ancient sky

Main article: Declination

Main article: Precession of the equinoxes

When studying how ancient people understood the sky, researchers often need to recreate the sky as it looked in the past. This helps place their findings in the right historical context.

To understand which stars or parts of the sky ancient structures faced, scientists use a system based on the stars' positions. Stars appear to move in circles around the North or South Celestial Pole. The distance of a star from this pole is called its declination. By knowing the declination of a structure’s direction, we can tell which stars or the Sun could have been seen there.

The Sun’s position changes throughout the year, moving between limits marked by the solstices. By calculating the declination a site was built to face, researchers can confirm if it aligns with important solar events without waiting for the exact date.

The Moon’s movements are more complex. It moves faster than the Sun and follows a different path, called lunistices, which shifts over an 18.6-year cycle. Moon phases also follow their own cycle, called the Synodic month, adding another layer of complexity.

Over thousands of years, the positions of the stars appear to shift due to a slow wobble in Earth’s axis, called precession. This means that stars rise and set in slightly different places over time. For example, the Egyptian pyramids were once aligned with a star called Thuban, which is no longer the North Star today. Similarly, the date someone was born under changed from Capricorn to Sagittarius over time due to this wobble.

Other sky events, like solar eclipses, can help date historical events. For example, a solar eclipse mentioned by the ancient writer Herodotus helped pinpoint a battle to May 28, 585 BC. Comets, like Halley’s Comet, are somewhat predictable, but many others appear unexpectedly. Meteor showers and other phenomena like auroras and rainbows were also observed by ancient peoples, though they are hard to predict.

Major topics of archaeoastronomical research

What has the study of the stars brought into the lives of different groups throughout history? The answers are many and varied.

One important reason people studied the sky was to create calendars. Ancient farmers, like those described in Hesiod's guide to farming, used the positions of the Sun and signs from nature, such as bird migrations, to know when to plant and harvest crops. For example, the Hopi people of the southwestern United States watched where the Sun rose and set to decide the best times for planting. Calendars helped communities plan events and activities together.

Myths and stories about the universe also came from watching the sky. Different cultures used these stories to explain how they saw the world. For instance, the Incas arranged their empire around their beliefs about the cosmos. The capital city, Cusco, was the center, with lines called ceques connecting it to different parts of the empire. These lines matched the way the Milky Way appeared in the sky.

People also used the sky to show power. Leaders sometimes wore special clothing with symbols from the stars. In some places, buildings were designed so that the Sun would shine in a special way on important days, showing the power of leaders and sacred places.

Major sites of archaeoastronomy interest

Main article: List of archaeoastronomical sites sorted by country

Clive Ruggles and Michel Cotte edited a book about special places linked to the stars. They talked about sites all around the world that show how ancient people thought about the sky.

At places like Stonehenge in England and Carnac in France, and also in Egypt and Yucatán, we find old buildings that seem to point to stars and the Sun. These places show how much effort people put into understanding the sky, just like how we explore space today.

Newgrange

Main article: Newgrange

Newgrange is an old tomb in Ireland from around 3,300 to 2,900 BC. For a few days around the Winter Solstice, light shines through a special opening into the tomb. This light does not come in through the main door but through a small hole above it. This shows that the tomb was built to include the Sun in its design.

Egypt

Since measurements of the Giza pyramids were first made, people have wondered how the ancient Egyptians decided where to build them. One idea is that they watched two stars in the Plough, which they called the thigh. They might have used these stars to find true north. Some think the pyramids were arranged like stars in Orion's belt, but this idea is debated. The pyramids may also connect to special moments when the Sun shines in certain ways.

The tomb of Senenmut has a ceiling with drawings of stars arranged in circles, showing how ancient Egyptians saw the night sky.

El Castillo

Main article: El Castillo, Chichen Itza

El Castillo, also called Kukulcán's Pyramid, is a step-pyramid in the Mayan city of Chichen Itza in Mexico. The pyramid has 365 steps, which might connect to the number of days in a year. During the equinoxes in March and September, a shadow appears on the pyramid that looks like a snake descending the steps.

Stonehenge

Stonehenge in England has many possible connections to the Sun and Moon. The most famous is when the Sun rises over a special stone during the summer solstice. Some think the winter solstice might be more important. Stonehenge is widely accepted as having astronomical meaning.

Maeshowe

Main article: Maeshowe

Maeshowe is an old tomb in Scotland. During the winter solstice, the Sun shines into the tomb through the entrance. Studies show that the tomb’s design points toward special sunset views and may have been used as a calendar.

Uxmal

Main article: Uxmal

Uxmal is a Mayan city in Mexico. The Governor's Palace there points toward where the planet Venus appears in the sky. This alignment happens every eight years and may connect to important events like the start of the rainy season.

Chaco Canyon

In Chaco Canyon, home of the ancient Pueblo culture, many buildings and roads seem to point toward the Sun and Moon. One famous site uses sunlight and shadows to mark important days like the solstices and equinoxes.

Lascaux Cave

Recent studies suggest that paintings in the Lascaux Cave in France might show pictures of stars. Some dots and shapes could represent constellations like Taurus and the Pleiades. Researchers think these paintings might be very old star maps.

Fringe archaeoastronomy

Archaeoastronomy sometimes gets a bad name because people have used it to support unusual ideas that aren't based on solid facts. In the 1930s, a person named Otto S. Reuter wrote a book claiming that ancient Germanic people knew more about the stars than others, like those from the Ancient Near East.

More recently, some people tried to say that writings in West Virginia described special star events, but other experts said these ideas didn’t make sense.

Sometimes, archaeoastronomy is linked to trying to find secret math rules in old buildings like Stonehenge.

India

For a long time, some have tried to use star studies to show that ancient Indian culture went back even further than people thought, to around 4000 BC. But experts have warned against these uncontrolled theories.

Organisations

There are several groups for people who study how past cultures understood the sky.

The ISAAC – the International Society for Archaeoastronomy and Astronomy in Culture started in 1996 to support this field. It helps organize meetings and publishes a journal.

SEAC, or La Société Européenne pour l'Astronomie dans la Culture, began in 1992 to focus on Europe. It holds yearly meetings and publishes reports.

SIAC, or La Sociedad Interamericana de Astronomía en la Cultura, started in 2003 to study Latin America.

SCAAS, the Society for Cultural Astronomy in the American Southwest, was created in 2009 to explore the sky knowledge of native peoples in the Southwestern United States. It has held many meetings and workshops.

AAAC, the Australian Association for Astronomy in Culture, began in 2020 in Australia to study Aboriginal and Torres Strait Islander sky traditions.

The Romanian Society for Cultural Astronomy started in 2019 and holds yearly meetings.

SMART, the Society of Māori Astronomy Research and Traditions, was founded in Aotearoa/New Zealand in 2013 to focus on Maori sky knowledge.

Native Skywatchers began in 2007 in Minnesota, USA, to share the star knowledge of Native American peoples like the Lakota and Ojibwe.

Publications

Some journals publish papers about archaeoastronomy. The Journal for the History of Astronomy has published many papers about this topic, and for twenty-seven years it also had a special part called Archaeoastronomy. Other journals, like the Journal of Astronomical History and Heritage, Culture & Cosmos, and the Journal of Skyscape Archaeology, also share research about archaeoastronomy.

Academic programs

Many universities around the world have special programs to study how ancient cultures understood the sky. One example is the Sophia Centre for Cosmology in Culture at the University of Wales - Trinity Saint David in the UK. Another is the Cultural Astronomy Program at the University of Melbourne in Australia. The Tata Institute of Fundamental Research has also made interesting discoveries in this area.