One important assumption that scientists make is that natural law is universal in space and time—that the laws that are active now were the same billions of years ago and throughout the universe. It's one of those accepted principles that beautifully fits the data we have access to, but with the acknowledgment that it can never be fully tested. After all, there's no reason to believe that we can even see all of the universe, let alone test laws at distances of billions of light years. The principle is accepted, though, because so far it works better than any other system we've found.
On a short time frame, the assumption tells us much about our
Southwestern region's past. By knowing how climate affects tree-ring growth, we can
reconstruct ancient climates from wood preserved from the past. And from a different
angle, we can do the same from the bones of animals from archaeological sites, or the
cycles of growth and non-growth of cave formations. When all lines of evidence point in
the same direction, we're obviously doing something right!
Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.
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.