DURHAM, ENGLAND—The Los Angeles Times reports that ancient records of lunar and solar eclipses have helped scientists to determine that the time it takes for the Earth to spin once around its axis has increased by an average of 1.8 milliseconds per century. Recently retired astronomer Richard Stephenson began the project 40 years ago at the University of Essex, and continued the work at Durham University, where he memorized 1,500 Chinese characters so that he could decipher astronomical records kept between A.D. 434 and 1280. He also analyzed data from Babylonian cuneiform tablets written between 720 and 10 B.C., the work of Arab astronomers working between A.D. 800 and 1000, and medieval European records. “People recording these things never had the slightest notion that what they were doing would lead to people in our generation actually studying changes in the Earth spin,” Stephenson said. “We are very much at the mercy of these ancient chroniclers and astronomers.” Stephenson would like to add the observations of the Maya and the Incas to the data set, and to find additional data dating from A.D. 200 to 600. To read in-depth about cuneiform tablets, go to “The World's Oldest Writing.”
