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🌍 Inside the Earth 3D

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Mantle

Depth
35 km → 2,890 km
State
Solid rock that flows very slowly (cm per year)
Temperature
≈ 500 → 4,000 °C
Made of
Peridotite: silicates rich in magnesium and iron

84% of Earth's volume. Hot rock creeps in convection currents that drag the tectonic plates. The top part plus the crust forms the rigid lithosphere.

  • Nobody has drilled through the crust: the deepest hole, Kola (Russia), stopped at 12.3 km in 1989 — 0.2% of the way to the centre.
  • Instead we use earthquake waves. P-waves (push–pull) travel through solids and liquids; S-waves (side-to-side) only through solids.
  • S-waves never arrive more than ≈ 103° from a quake — the S-wave shadow zone — so part of the core must be liquid. Switch on the waves to see it.
  • Earth’s average density (5.5 g/cm³) is twice that of surface rocks, so the centre must be very dense — iron.
  • Meteorites, made of the same stuff as Earth, give us the overall recipe.