This finding, confirmed only within the past two years, quickly led to the conclusion that Earths solid-iron inner core is anisotropic -- it has a directional quality, a texture similar to the grain in wood, that allows sound waves to go faster when they travel in a certain direction. What, exactly, is the nature of this inner-core texture? To this question, the seismic data responds with sphinx-like silence. The problem, says Ronald Cohen of the Carnegie Institution of Washington, is then were stymied. We know theres some kind of structure, the data tells us that, but we dont know what it is. If we knew the sound velocities in iron at the pressure and temperature of the inner core, we could get somewhere. To remedy this lack of information, Stixrude and Cohen turned to the CRAY C90 at Pittsburgh Supercomputing Center. psc.edu/science/Cohen_Stix/cohen_stix.html
Posted on: Mon, 12 Jan 2015 20:34:17 +0000