The Earth’s crust is the outermost layer of the Earth’s structure. In fact, the crust is what you’re standing on. But geologists have learned that if you dig down into the Earth, even just a few hundred meters, and things start to heat up. The inside of the Earth is hot! But what is the temperature of the Earth’s crust?
The crust is the outermost layer of the Earth; it’s a thin shell of rock that measures just 30 km thick at the continents, and 5 km thick underneath the oceans. Just 1% of the Earth’s mass is made up of its crust.
At its outer edge, where it meets the atmosphere, the temperature of the crust of the Earth is the same temperature as the air. So, it might be as hot as 35 °C in the desert and below freezing in Antarctica. But if you dig down, the temperatures go up. Once you reach the mantle – the next layer of the Earth – the temperatures have risen from 200 °C (392°F) to 400°C (752°F).
The deepest mine in the world is the TauTona gold mine in South Africa, measuring 3.9 km deep. This is only about 10% of the depth of the crust in Africa, and yet the temperatures down at the bottom of the mine reach a sweltering 55 °C. The mine needs air conditioning to bring the temperature down to the point that it’s comfortable for miners to work all day.
We’ve also recorded an episode of Astronomy Cast all about planet Earth. Listen here, Episode 51: Earth.