Most modern scientists would agree that the most important ingredient in the scientific method is the collection of data. Patterns in the phenomena can be described even when one has no idea why they occur—indeed, we will see many examples of such empirical models—but it’s impossible to describe what is going on without knowing what is going on. Good ideas that explain the facts therefore must come only after their discovery, unless they are predicted as a result of some existing evidence. It should be no surprise, then, that the earliest contributions to astronomy came in the form of maps of celestial cycles.
The name for the archaeological study of places with astronomical significance is archaeoastronomy. A particularly interesting example is the Anasazi Sun Dagger, located on Fajada Butte in Chaco Canyon, New Mexico. Sunlight shines through three rock slabs which lean against the southeastern facing cliff, producing two narrow slits of light on the cliff wall. These “sun daggers” shine on spiral petroglyphs etched into the wall, marking important astronomical events (Figure 2-1). A large spiral petroglyph is bisected by a single dagger at noon on the summer solstice, and its outside edges are framed by the two daggers at noon on the winter solstice. At midday on the vernal and autumnal equinoxes, one dagger bisects a small spiral petroglyph while the other is just to the right of the large spiral. In addition to capturing these important astronomical events, the shadow cast at moonrise is thought to be significant: at major standstill, the entire large petroglyph is illuminated, at minor standstill it is half in shadow, and when the moon is on the ecliptic the entire large petroglyph is in shadow. (See Glossary definition of lunar standstill).
The Anasazi Sun Dagger site is remarkable because it captures such a large number of important astronomical phenomena in one simple structure. In a style that is typical of Native American cultures, the site barely appears as a disturbance to the natural setting. For more information on the site, including the original research papers, you are encouraged to visit The Solstice Project’s website. In particular, the original Science paper can be accessed there, or at the link provided in the Supplementary Resources.
The Anasazi’s Sun Dagger is just one of many prehistoric sites from around the world that were constructed according to precise astronomical alignments. An excellent resource with links and references to information on the ancient astronomy of many cultures around the world can be found here. As you explore this resource, you should come to appreciate how ubiquitous the detailed knowledge of the sky and of recurring astronomical phenomena was among human cultures. Some, like the Mayans, Egyptians and the builders of Stonehenge, constructed grand edifices incorporating these phenomena; others, like the Anasazi, created structures that blend into the natural landscape. Regardless of how each culture’s knowledge of celestial phenomena was displayed in their architecture, it is evident that humans have commonly sought a detailed knowledge of the night sky, and have gained that knowledge everywhere through many years of observation.
Often, this knowledge—of the Sun’s location throughout the year, or of the positions of various objects in the night sky—became the subject of stories that sought to explain things like the placement of certain patterns of stars, or asterisms. Such stories would often link the placement of the stars in the sky with explanations of terrestrial phenomena. One story of the origin of the Big Dipper, an asterism that was often described as the Big Bear in the traditional stories of North American Indigenous peoples, is told by Wilfred Buck, an elder from the Opskwayak Cree Nation of Northern Manitoba:
This story posits an explanation of why, in September-October when the Big Dipper comes near the northern horizon in the Canadian night sky, the leaves on deciduous trees turn red.
From a modern scientific perspective, stories like these which have been part of many cultural and spiritual traditions around the world, could be described as first attempts to explain the data. In that case, they represent an important step in the development of the scientific method, as they attempt to explain the phenomena that do occur, sometimes using very detailed observations, by proposing reasons for their occurrence. But while they go this far, they typically do not draw a logical connection between cause and phenomenon that is supported by further evidence, which is an important aspect of the scientific method. Credit for adding that next step is owed to the ancient Greeks, who applied logic—i.e. valid reasoning—to the search for an explanation of the facts.
cosmiCave.org 