An anonymous reader writes "A University of California, Berkeley, geophysicist has made the first-ever measurement of the strength of the magnetic field inside Earth's core, 1,800 miles underground. The magnetic field strength is 25 Gauss, or 50 times stronger than the magnetic field at the surface that makes compass needles align north-south. Though this number is in the middle of the range geophysicists predict, it puts constraints on the identity of the heat sources in the core that keep the internal dynamo running to maintain this magnetic field."

evil agent passes along an article in Scientific American reporting that new radiocarbon dating techniques have cast doubt on the accepted story of how the Americas were populated. In the traditional view, "[M]igrants out of northeast Asia slipped into the Americas bearing finely shaped stone projectiles, so-called 'Clovis points,' after the town in New Mexico where they were first uncovered. This Clovis culture rapidly spread throughout the empty continents and by 1,000 years after their arrival had reached the southernmost tip of what is now South America, making them the original ancestors of indigenous Americans." The new dating of Clovis sites suggests that "Clovis" was not a people, but rather a technology. That is, a new and more efficient method of making arrowheads for hunting spread rapidly through a pre-existing population in both North and South America, over at most 350 years.