The River and the Sky: Astronomy and Topography in Caral Society, America's First Urban Centers

TL;DR

This study reveals that the orientation of early urban structures in Caral, Peru, was influenced by both the river's course and astronomical events, marking one of the earliest land- and skyscape interactions in the Americas.

Contribution

It demonstrates the combined influence of topography and astronomy on the urban planning of America's first known urban centers, highlighting cultural and environmental integration.

Findings

Structures aligned with river and astronomical events

Moonrise and solstice orientations linked to seasonal cycles

First evidence of land- and skyscape interaction in the Americas

Abstract

America's first urban centres were allegedly located at the Supe Valley sites in Peru. After investigating the location and the orientation of the main built structures, we show that it is not only the presence of the River Supe that determines their orientation but also astronomical relationships within the orientation of the buildings dictate their setting within the valley. The southernmost position of moonrise on the horizon seems to be the most important astronomical target. There is the possibility of an evolution toward attributing greater importance to the June solstice sunrise and the rising of certain stars or asterisms. These orientations could elate to specific moments throughout the year, in particular to seasonal rains, subsequent river flooding, and agricultural cycles. This is one of the earliest examples of the interaction of land- and skyscapes in human cultures and indeed the first in the Americas.