11 November 2011

What Is It Like At The Earth's Core?

Ever imagine what the center of the Earth looks like? Scientists at the Spring-8 Synchrotron near Osaka, Japan think they may have the answer. According to Japanese scientist Kei Hirose, he has recreated the conditions found at the Earth's core.

Using iron-nickel alloy, he subjected the material to three million times the atmospheric pressure and heated it to 4,500 Celsius. The procedure resulted in the rapid growth of crystals in the element. Iron-Nickel alloy is believed to make up the Earth's core.

The experiment suggests that at the center of the Earth, one may find a "forest" of huge crystals, around 10 kilometers tall. These crystals have grown to these gargantuan size because of the constant pressure and heat the materials have been subjected to for billions of years. As their research suggests, these crystals will grow pointing towards the North Pole.

According to his study, "Earth’s solid inner core is mainly composed of iron (Fe). Because the relevant ultrahigh pressure and temperature conditions are difficult to produce experimentally, the preferred crystal structure of Fe at the inner core remains uncertain. Static compression experiments showed that the hexagonal close-packed (hcp) structure of Fe is stable up to 377 gigapascals and 5700 kelvin, corresponding to inner core conditions. The observed weak temperature dependence of the c/a axial ratio suggests that hcp Fe is elastically anisotropic at core temperatures. Preferred orientation of the hcp phase may explain previously observed inner core seismic anisotropy..."
Source: sciencemag.org

Video: Professor Kei Hirose reveals the results on his study of the Earth's core

Meanwhile, an experiment recreating the extreme conditions at the centre of the Earth recently was launched. The project is based in European Synchrotron Radiation Facility near Grenoble, France. They will be using x-ray beams to recreate the temperature and pressure to which the materials are subjected.

It is virtually impossible to drill to the center as the core is around 3,000 kilometers (1,900 miles) below sea level. At it's thinnest, the crust is 10 kilometers thick.

The experiment attempts to reveal questions such as the planet's magnetic field; how it came about, why it changes, and how shock waves travel through it. It could also reveal why the Earth's magnetic field can "flip".

Video: Dan Lathrop on the mystery behind the magnetic field at the center of the Earth