We all have a tendency to put on weight with age, and the Chihuahuan Desert is no exception. What? How does a desert gain weight? Simple. In a word, stardust!
Plowing through space, Earth encounters minute particles left over from the destruction of long-dead stars—the very stuff from which not only our solar system, but we ourselves are constructed—along with the sheddings of comets and the debris resulting from clashes between asteroids. Most of these bits of matter are in turn made up of numerous smaller particles, each with a story to tell of outer-space loneliness or journeys from the outer reaches of the solar system or the chaos of the asteroid belt.
Slowed by collision with earth's atmosphere, these microscopic
particles become concentrated and eventually drift to the ground, adding—by one
estimate—some 100 tons of matter to the earth annually. On average, each square yard of
our desert gains one such alien immigrant every day. Like people, our desert's
daily weight gain is almost unnoticeable, but in the long run, appreciable.
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.
Holmes, H. 2001. Stardust. Discover, 22(9):52-59.
Astronomy Today—Meteors