The Nubian Aquifer, the font of fabled oases in Egypt and Libya, stretches languidly across 770,000 square miles of northern Africa, a pointillist collection of underground pools of water migrating, ever so slowly, through rock and sand toward the Mediterranean Sea.
The aquifer is one of the world’s oldest. But its workings — how it flows and how quickly surface water replenishes it — have been hard to understand, in part because the tools available to study it have provided, at best, a blurry image.
Now, to solve some of the puzzles, physicists at the Department of Energy’s Argonne National Laboratory in Illinois have turned to one of the rarest particles on earth: an elusive radioactive isotope usually ricocheting around in the atmosphere at hundreds of miles an hour.
Sunday, December 04, 2011
A Rare Isotope Helps Track an Ancient Water Source
New York Times