Volcanoes occur when hot magma from inside the Earth reaches the surface and erupts as lava, ash and rock. So we know the interior of the Earth is hotter than the surface. But how hot is the core of the Earth?
The Earth is roughly a sphere, with a radius of 6,371 km. In other words, you’d need to dig a tunnel down 6,371 km to reach the center of the Earth; it’s hottest place. Geologists believe that the core of the Earth is made up of metals, like iron and nickel, and it’s probably in a solid state, surrounded by a shell of liquid metal. The inner core is the hottest part of the Earth, and measures 2,440 km across.
It’s down in this inner core where you’d find the hottest part of Earth. Scientists have estimated that the temperature of the core reaches 5,700 kelvin (5,430 °C; 9,800 °F).
We’ve also recorded an episode of Astronomy Cast all about planet Earth. Listen here, Episode 51: Earth.