TSUKUBA, JAPAN—Scientists led by Yasuyuki Mitsuma of the University of Tsukuba have found evidence of solar magnetic storms that took place sometime between 679 and 655 B.C. in radioisotope data collected from ancient trees and records kept on cuneiform tablets by ancient Assyrian astronomers. Some 2,700 years ago, astronomers in Babylon and Nineveh documented an unusual red glow in the sky on three separate cuneiform tablets, he explained. Mitsuma and his colleagues suggest this phenomenon may have been what are now known as stable auroral red arcs, which consist of light emitted by electrons in atmospheric oxygen atoms excited by intense magnetic fields. Tree ring data also registered a rapid rise in radioactive carbon-14 in the environment, which is associated with increased solar activity, at this time. Mitsuma said the information pushes the history of known solar activity back a century, and could help scientists predict future magnetic storms. To read about Babylonian astronomers' planetary calculations that are recorded on cuneiform tablets, go to "The World's Oldest Writing."