Polar Games
Guide

Layers of the Earth: Crust, Mantle and Core

The layers of the Earth, from crust to inner core: thickness, temperature, solid or liquid, the lithosphere and asthenosphere, the deepest hole ever drilled and a hard-boiled egg model.

By Polarzinho ·

Official Deepforge cover art

In Deepforge I dig a copper mine and go down chamber by chamber. The deeper I go, the hotter and weirder it gets. The real Earth is similar, only the trip is far longer.

Here you get the layers of the Earth, the thickness and temperature of each, what is solid and what is liquid and an easy model you can make with a hard-boiled egg.

Play Deepforge

The four layers of the Earth

  1. Crust: the outer layer, where we live. It is thin and solid, from about 5 to 70 km thick, thinner under oceans and thicker under mountains.
  2. Mantle: the thickest layer, about 2,900 km. It is hot rock that can flow very slowly, like thick dough.
  3. Outer core: about 2,200 km of molten iron and nickel. The motion of this liquid metal helps create Earth's magnetic field.
  4. Inner core: a ball of iron and nickel about 1,200 km in radius. Despite the extreme heat, it is solid because of the enormous pressure.

Lithosphere and asthenosphere

  • Lithosphere: the crust plus the rigid top of the mantle. It is broken into big pieces, the tectonic plates.
  • Asthenosphere: the part of the mantle just below, hotter and softer, where the plates slowly slide.

Plate movement causes earthquakes, builds mountains and creates volcanoes.

How much hotter it gets

Temperature rises with depth. Near the surface, it goes up about 25 to 30 °C per kilometer. At the center, scientists estimate around 5,000 to 6,000 °C, similar to the surface of the Sun.

The deepest hole ever drilled

The Kola Superdeep Borehole in Russia reached about 12 km deep. That sounds like a lot, but it is just a fraction of the crust at its thickest, and tiny compared with the mantle.

Experiment: the hard-boiled egg Earth

  • The shell is the crust. Thin and brittle.
  • The white is the mantle. The thickest part.
  • The yolk is the core.

Cut a hard-boiled egg in half with a knife (ask an adult for help) and compare. It looks a lot like the Earth layers diagram in textbooks.

Going down in Deepforge

In Deepforge, you go down through 30 mine chambers, across six biomes. It all starts in a copper mine, with dirt and stone.

Chamber 1 of Deepforge in the Copper Mine: four copper picks on the bench, a mine of dirt and stone, 30 coins, the BUY 40 and DIG buttons and a bubble saying to drag a pick onto a matching one
Deepforge: the first chamber, in the Copper Mine.

Deeper down, the volcanic depths have flowing lava and gold veins.

Volcanic Depths in chamber 11: lava waterfalls behind a mine of dark stone and gold veins, four picks digging, the objective Mine 3 gold ores at 2/3 and a dynamite crate on the left

PolarzinhoLava, gold and dynamite. If that is not the mantle, it is close.

Deepforge: lava, dark stone and gold veins.
Chamber 6 in the Crystal Cavern biome: the objective Collect 3 crystals reads 3/3 with a lit star, the mine is mostly cleared and a pick closes in on a cracked core
Deepforge: the crystal cavern, with a cracked core.

FAQ

What are the layers of the Earth?

Crust, mantle, outer core and inner core.

What is the thickest layer?

The mantle, about 2,900 km thick.

Is the Earth's core liquid or solid?

The outer core is liquid and the inner core is solid.

What is the Earth's core made of?

Mainly iron and nickel.

Your turn

Order from closest to the surface to deepest: inner core, crust, outer core and mantle. Answer: crust, mantle, outer core and inner core.

Play Deepforge