Using a series of very technical tests, scientists from the French research facility CEA have determined that the Earth's core is roughly 6,000 degrees Celsius. That is approximately 1,000 degrees hotter than the temperature obtained by tests in the 1990s.

These new figures show that the center of the Earth is just as hot as the surface of the sun.

The experiment that supplied the new temperature used X-rays to probe tiny samples of iron at extraordinary pressures to examine how the iron crystals form and melt. The BBC reported that "To replicate the enormous pressures at the core boundary - more than a million times the pressure at sea level - they used a device called a diamond anvil cell - essentially a tiny sample held between the points of two precision-machined synthetic diamonds.

Once the team's iron samples were subjected to the high pressures and high temperatures using a laser, the scientists used X-ray beams to carry out "diffraction" - bouncing X-rays off of the nuclei of the iron atoms and watching how the pattern changed as the iron changed from solid to liquid."