Scientific aspects of Hāpaiali‘i heiau

A heiau is a Hawaiian pre-Christian place of worship composed of rocks and holding historical and cultural significance, with a variety of uses ranging from worship to rituals. The scientific origins of Hawaiian heiau have yet to be fully inspected in the literature. This paper covers Hāpaialiʻi heiau on the island of Hawai‘i and its main function as a seasonal calendar through continuous observation of the sunrise and sunset locations over the sea horizon. Understanding the calendar functionality of the heiau contributes an essential step towards understanding Hawaiians’ use of indigenous science. This study mathematically investigates the sacred structure’s functionality with numerical accuracy and scientific rigour. A brief overview of the history of the Kahaluʻu area and the surrounding heiau provides important context for the heiau’s significance. This study reports and analyses the heiau’s relevant history, cultural significance and reconstruction by Kamehameha Schools. The importance of the calendar lies in the determination of the responsibilities for the current season, indicating which crops are to be harvested and which fish are in the mating season. In the mathematical analysis, the coordinates of the stones within the heiau are independently measured using Google Earth and Google Maps. The relative distances and angles between the internal stones are calculated using Google Sheets and Matlab to discover the underlying sciences possibly used by ancient native Hawaiians.