The laboratory results point to the possibility that a thin jet of relatively cold molten iron is streaming down across the liquid outer core from an area in the mid-Pacific to Earth s solid iron inner core. But Sumita has developed several direct ways to use the model to answer questions about observations relating to the Earth s core. The Earth's molten outer core lies beneath the rocky mantle, which includes the surface. Because of this close relationship, understanding the core s activity should help scientists better understand the mantle s behavior. It's not possible, however, to directly observe the outer core.
Scientists can image the solid inner core using energy from earthquakes, known as seismic waves.
But this reveals little of the liquid outer core. Scientists can link changes in the strength and direction of magnetic fields above ground to the ebb and flow of molten iron below ground, Sumita explains. For example, we can interpret the westward motion of the magnetic field patches as a manifestation of the westward flow in the core. A heater was placed at one spot on the rim of the hemisphere to imitate the uneven transfer of heat between the mantle and the outer core. Because the direction of the centrifugal force in the experiment is opposite to that of the Earth's gravity, this corresponds to a cold region found in the lower mantle of the Earth which causes a downward flow in the core.