The Enigma 1,800 Miles Below Us
As if the inside story of our planet werent already the ultimate potboiler, a host of new findings has just turned the heat up past Stygian.
Geologists have long known that Earths core, some 1,800 miles beneath our feet, is a dense, chemically doped ball of iron roughly the size of Mars and every bit as alien. Its a place where pressures bear down with the weight of 3.5 million atmospheres, like 3.5 million skies falling at once on your head, and where temperatures reach 10,000 degrees Fahrenheit as hot as the surface of the Sun. Its a place where the term ironclad agreement has no meaning, since iron cant even agree with itself on what form to take. Its a fluid, its a solid, its twisting and spiraling like liquid confetti.
Researchers have also known that Earths inner Martian makes its outer portions look and feel like home. The cores heat helps animate the giant jigsaw puzzle of tectonic plates floating far above it, to build up mountains and gouge out seabeds. At the same time, the jostling of core iron generates Earth magnetic field, which blocks dangerous cosmic radiation, guides terrestrial wanderers and brightens northern skies with scarves of auroral lights.
Now it turns out that existing models of the core, for all their drama, may not be dramatic enough. Reporting recently in the journal Nature, Dario Alfè of University College London and his colleagues presented evidence that iron in the outer layers of the core is frittering away heat through the wasteful process called conduction at two to three times the rate of previous estimates.
http://www.nytimes.com/2012/05/29/science/earths-core-the-enigma-1800-miles-below-us.html?_r=1&nl=todaysheadlines&emc=edit_th_20120529