The Earth's core is far hotter than first thought

Experiments using X-rays to probe tiny samples of iron at extraordinarily high pressures have been undertaken to see how the iron crystals form and melt. These experiments have given indications as to the temperature of which the crystal can form

 

New measurements suggest the Earth's inner core is far hotter than prior experiments suggested, as hot as the Sun's surface at around 6000C. The scientists used iron samples subjected to the high pressures and high temperatures using a laser, then the X-ray beams carry out "diffraction" - bouncing X-rays off the nuclei of the iron atoms and watching how the pattern changed as the iron changed from solid to liquid. Those diffraction patterns give more insight into partially molten states of iron, which the team believes were what the researchers were measuring in the first experiments. (BBC website)

 

The centre of the Earth has been previously studied using seismic waves and their velocities through the Earth, it can give a great deal of information on thicknesses and densities of layers within the Earth and give some indications of temperatures along with their liquid of solidified state.