earth science: getting to the core of the matter

Unless you’re a character in a Jules Verne novel, journeying to the center of the earth remains impossible. So researchers interested in understanding the still somewhat mysterious inner workings of our planet’s iron-rich core must obtain their information indirectly, for example, by measuring seismic waves traveling through the earth’s interior. But by replicating the intense pressures and temperatures found at the core in a lab, physicists Jeffrey H. Nguyen and Neil C. Holmes have now shed some light on how iron behaves deep inside the earth. In the January 22 Nature, the Lawrence Livermore National Laboratory researchers report subjecting a sample of iron to shockwaves generated by a gas gun, which creates pressures millions of times the pressure of air at the earth’s surface. From their experiments, the researchers discovered that iron at earth-core conditions melts at a temperature of about 8,720 degrees Fahrenheit. “By determining the melting point of iron, we can estimate the temperature at the core boundaries,” Nguyen stated in a press release. “This information provides us with another tool to study the temperature of the Earth’s core.”

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 1/27/2004.