Earth's Core Caught in Phase Shift 'Dance'

Scientists from the University Joseph Fourier (UJF), in Grenoble, believe that our planet's solid core may be caught in an endless loop of melting and liquefying. The processes partially affect the innermost, solid core, in the sense that the entire structure is moving through the mantle. As it does so, the team proposes, the front areas of the core (as determined by the direction of movement) melt, while the areas in the back solidify. Thus, the formation remains constant, yet always on the move. The motion was calculated as being visible relative to Earth liquid outer core, OurAmazingPlanet reports.

“Within less than 100 million years, everything that has been crystallized on the west will have melted on the east,” explains UJF professor Thierry Alboussiere, the lead researcher on the new investigation. The new idea however goes up directly against established theories of what goes on inside the planet. The widely-accepted view is that the inner core stands still, while growing in all directions. As the planet cools, the basic laws of physics dictate that the solid core should be getting large, but the new work proposes that other mechanisms could be at work influencing the process.

Planetary scientists agree that Earth's magnetic field is caused by the movement of chemicals inside the planet. As the central iron core gets larger and cooler, attracting more and more heavy elements, the outer fringes of the core, the mantle and the crust are stuck with lighter elements. This inter-change is thought to be the main driving force that fuels the magnetic field. While knowing precisely what goes on inside the core is impossible without direct observations, some data do literally pop up, via earthquakes and volcanic eruptions.

“Whenever there is a big earthquake, seismic waves get sent out in all directions and seismographs around the globe record the wiggles,” explains Bard College expert Michal Bergman. He was not directly involved in the French research, but wrote a commentary on the work in the latest issue of the esteemed scientific journal Nature. The waves can give us indications of what elements can be found at which location in the core. But “earthquakes don't occur everywhere on the surface of Earth, so we don't have enough data to completely constrain the inner core. We have to take what nature can give us,” Bergman says.