Teacher background information

This elaboration will enable students to gain knowledge and awareness of Aboriginal and Torres Strait Islander understandings of and perspectives on the phases of the moon and the relationship between the lunar cycle and ocean tides.

The traditional astronomical knowledge of Australia’s First Nations’ communities includes an intricate understanding of the relationship between the moon and tides. This knowledge was acquired through empirical observation of how ocean tides are related to the positioning of the moon and sun relative to the Earth. Some Aboriginal and Torres Strait Islander groups’ astronomical awareness of the relationship between the moon and tides was more accurate than early European scientific understandings.

With the full benefit of contemporary astronomical understandings revealed by modern technology, scientists now agree that the Earth’s tides are a result of gravitational interactions between the moon, sun and Earth. Tides consist of what appears to be a rising and falling of oceans namely, high tides and low tides. Despite the fact that the sun has an overall greater gravitational pull than the moon, it does not have as significant an impact on ocean tides. This is mainly due to the close proximity of the moon to the Earth.

The phases of the moon provide an indication of the combined gravitational strength of the moon and sun, which influence the tides on Earth. When the moon is full or new, high tides become very high and the low tides very low; this is referred to as spring tides. During this time the gravitational pull of both the sun and moon contributes to the tides. Contrarily neap tides occur when the moon is in its quarter phases and result in tides becoming exceptionally weak. These tides occur when the moon and sun are perpendicular to each other in relation to the Earth.

The knowledge and awareness of neap tides and their subsequent reduction of currents are well-known to Torres Strait Islander peoples. The understanding of how lunar cycles are related to the occurrence of neap tides allows Torres Strait Islander peoples to predict the safest periods to be diving on reefs for lobsters.

First Peoples across mainland Australia and Torres Strait Islander peoples have many different explanations for the apparent movement of celestial bodies, including the moon. This traditional knowledge extends beyond symbolic representation and includes awareness of every observable object in the sky, and the relationships between their movements and natural occurrences on Earth.

Aboriginal peoples, for example, the Yolngu of the Northern Territory, have detailed stories that explain the phases of the moon and also accurately link the moon with the changing tides. Since the Yolngu people rely on the sea for many resources, they have developed an in-depth knowledge of tides, including abilities to interpret the phases of the moon in ways that allow the prediction of ocean phenomena, such as the time and height of the next tide. In contrast, the 17^th century Italian astronomer Galileo did not believe that the moon was in any way connected to tidal phenomena.  

Aboriginal peoples of the Kimberley region of Western Australia, such as the Bardi people, also have comprehensive knowledge of both the moon and the tides and have traditionally been able to effectively utilise this knowledge to predict the best times for the collection of highly prized trochus shells, the best currents for fishing, and the safest times for the use of water-craft.

Traditionally, Aboriginal and Torres Strait Islander peoples did not quantify the attractive force of the moon’s gravity. However, they did have an understanding that there was a causal relationship between the lunar cycle and tides. This observed knowledge reflected cultural and spiritual beliefs and helped not only to make sense of the universe, but also assisted in making accurate predictions important to many aspects of daily life, such as the timing of gathering marine resources by water-craft.

Observations and understandings of astronomical movements and phenomena helped First Nations’ peoples shape their view of the universe and their place within it. The ontological knowledge associated with these phenomena reinforced important lessons and spiritual beliefs regarding their existence. Critically however, they also provided epistemological knowledge about the world derived from empirical observations, such as insights into seasonal changes and related behaviours of living things and assistance in navigation. They also provided the basis for making accurate predictions about recurring weather patterns and seasonal cycles. These insights helped develop both intricate and holistic understanding of the relationships between heavenly bodies and natural phenomena on Earth.

By investigating Aboriginal and Torres Strait Islander perspectives and cultural stories, students can gain an awareness of First Nations’ knowledge of the relationship between the lunar cycle and ocean tides. Through this perspective, students can also develop an understanding of how tides are determined by the relative positioning and gravitational forces between the moon, Earth and sun.