Astronomy is an ancient undertaking. A thousand years before the construction of the Very Large Array of radio telescopes in Socorro, New Mexico, the Mayans had built an observatory at ChichÌ©n ItzÌÁ, Mexico, and used it to calculate (among other things) the length of a solar year for the planet Venus (584 days).

The ancient Polynesians used their intimate knowledge of the night sky, wind patterns, and ocean currents to navigate hundreds of miles between small islands. Some of that knowledge can be seen in the carefully woven ‰ÛÏstick charts‰Û that have been preserved.

But a large portion of indigenous astronomical knowledge is in danger of being lost forever ‰ÛÒ part of an oral tradition that needs to be communicated faithfully through time. Brazilian physicist, Germano Bruno Afonso åÊis working to keep this cosmic information alive for future generations.

The land is the mirror of the sky,‰Û explains Afonso, Brazil’s leading scholar of ethno-astronomy. For a healthy society, the link between the two, he says, must be maintained. Toward this end, Afonso has built planetariums that combine western and indigenous science, and created educational programs in urban areas where native people are more likely to lose touch with their traditions.

The video, ‰ÛÏSkies Through Indigenous Eyes,‰Û documents Afonso’s fascinating work.