Earth's inner core is as hot as the surface of the Sun.

Research led by the French research agency CNRS and published in the journal Science confirms that Earth's inner core temperature is approximately 6,000 degrees Celsius, which is about 10,800 degrees Fahrenheit. This matches the temperature of the Sun's photosphere, the visible outer layer of the star. Scientists determined this by using X-rays to probe how iron samples behave under extreme pressure in a laboratory setting.The inner core is a solid ball of iron and nickel with a radius of about 760 miles. Even though it is hot enough to melt, the pressure at Earth's center is about 3.6 million times higher than at sea level. This immense pressure raises the melting point of iron, forcing the atoms into a solid state despite the thermal energy.The heat within the core comes from two primary sources. About half is primordial heat left over from the planet's violent formation 4.5 billion years ago. The other half is generated by the radioactive decay of elements like uranium, thorium, and potassium in the mantle and core.This heat is vital for life because it creates convection currents in the liquid outer core. This movement generates Earth's geodynamo, the magnetic field that protects our atmosphere from solar radiation. Without this internal furnace, Earth would become a cold, dead world similar to Mars.