What did ancient American cultures know about astronomy? History of Astronomy Read more from Chapter Astronomy Fundamentals

Ancient American cultures were very knowledgeable about astronomy, including lunar phases, eclipses, and planetary motions. Almost all of the many temples and pyramids of the Inca, Mayan, and other Meso-American cultures are aligned and decorated with the motions of planets and celestial objects.

For example, at Chichen Itza in southern Mexico, on the days of the vernal equinox (March 21) and autumnal equinox (September 21), shadows cast by the Sun create the vision of a huge snake-god slithering up the sides of the Pyramid of Kukulcan, which was built more than one thousand years ago. Farther north, among the Anasazi ruins of Chaco Canyon, New Mexico, the work of ancient Native American astronomers survives in the famous “sun dagger” petroglyphs, which appear to mark the solstices, equinoxes, and even the 18.6-year lunar cycle.