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Earth's innermost core discovery confirmed
Champaign, Ill. (UPI) Mar 13, 2008 U.S. geologists have created a three-dimensional model describing the seismic anisotropy and texturing of iron crystals within the Earth's innermost core. University of Illinois geologist Xiaodong Song and postdoctoral researcher Xinlei Sun discovered Earth's core, composed mainly of iron, consists of a solid inner core about 1,500 miles in diameter and a fluid outer core about 4,350 miles in diameter. The solid inner core is elastically anisotropic; that is, seismic waves have different speeds along different directions, the scientists said. "Our results suggest the outer inner core is composed of iron crystals of a single phase with different degrees of preferred alignment along Earth's spin axis," Sun said. "The inner, inner core may be composed of a different phase of crystalline iron or have a different pattern of alignment." The study has been accepted for publication in the journal Earth and Planetary Science Letters, and is posted on its Web site. Community Email This Article Comment On This Article Related Links Dirt, rocks and all the stuff we stand on firmly
The 10 Questions Shaping 21st-Century Earth Sciences
Washington DC (SPX) Mar 13, 2008Ten questions driving the geological and planetary sciences were identified today in a new report by the National Research Council. Aimed at reflecting the major scientific issues facing earth science at the start of the 21st century, the questions represent where the field stands, how it arrived at this point, and where it may be headed. |
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