A recent study from scientists at France's CEA research agency reveals that the Earth's core is as hot as the Sun's surface. According to the study, the temperature of the Earth's core is measured at 6,000 Celsius, a range on par with the temperature with the Sun's surface.
The study was led by Agnès Dewaele who stated everything in a press release. The experiment started by examining the earthquake-triggered seismic waves passing through the planet's mantle. The initial study bore fruit by telling how pressure in the Earth increases with depth. While it revealed that the pressure inside the Earth's core is 3.3 million times as what is felt in the surface, it did not say anything about the core's temperature.
This is when they went to the laboratory, where they subjected samples of crystalline iron to a device called diamond anvil cell, an apparatus holding the iron samples between two precision-machined diamond replicas. With the use of the amount of pressure determined by the initial study, the device was subject to the same amount of pressure present at the Earth's core.
According to researcher Yingwei Fei, knowing the exact pressure in the core is important because the iron's melting temperature plays an important role to the temperature of the core. "The accurate determination of the melting temperature of iron provides an important constraint on the core temperature, which is essential to understanding how the dynamic Earth works, including its heat budget, generation of its magnetic field, and the thermal evolution of the planet. High heat flux at the core-mantle boundary with a possible partial melting of the mantle," he wrote in the Science journal.
Together with the high amount of pressure, the iron samples were subjected to laser beams simulating the high temperature below the Earth's surface. This is where the European Synchrotron Radiation Facility stepped in, together with the X-ray instrument it developed. The instrument was used to monitor and measure the molecular changes in the structure of the iron samples. The iron samples began to turn into liquid—as what is present in the Earth's core—at a temperature around 6,000 Celsius.
The results of the study prove to be a major milestone because the core's temperature is one of the factors that produce the planet's magnetic field. “We are of course very satisfied that our experiment validated today’s best theories on heat transfer from the Earth’s core and the generation of the Earth’s magnetic field,” says Dewaele "I am hopeful that in the not-so-distant future, we can reproduce in our laboratories, and investigate with synchrotron X-rays, every state of matter inside the Earth.”