The newcomer to the desert often is struck dumb by the brilliance of its nighttime skies festooned with sparkling gems. Today, we understand the immense distances that starlight has traveled before striking our eyes and our fancy. However, this has not always been the case.
Because our eyes are set apart and see nearby objects from two slightly different angles, we have excellent three-dimensional vision—but only for objects relatively near by. Beyond a few tens of feet, the difference between the two views is so minute that this ability is lost. We do judge distances on farther objects, but by relying on size, overlap of objects, and distinctness and color.
In the sky, most such clues to distance are absent. In lieu of
knowledge to the contrary, the ancients believed the fixed stars were associated with
an inverted, bowl-shaped surface only a few miles away, with the wanderers—the sun, the
moon, and the planets—moving freely across this semi-sphere of the heavens. Those
brilliant desert stars were, indeed, almost within arms' reach.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.