A journey from core to cosmos.
Turn the Earth. Open a window into its interior. Explore the layers above your head.
Drag to turn · use + / − to zoom · arrow keys also rotate · tap a visible layer or choose its name below
One Earth, several useful maps.
From the model to your notebook.
Worked example: mean Earth radius ≈ 6,371 km. The core–mantle boundary lies about 2,891 km below the surface, so its radius is 6,371 − 2,891 = 3,480 km. Depth and radius run in opposite directions.
The inner-core boundary is about 5,150 km deep. What is its radius from Earth's centre, in km?
Hint and solution
Radius = surface radius − depth = 6,371 − 5,150 = 1,221 km. A radius is measured from the centre; a depth is measured inward from the surface.
Three investigations to try
1. Switch between expanded and physical scale. Why do the crust and lower atmosphere become hard to see?
2. Select outer core and inner core. Explain why high temperature does not require both to be liquid.
3. Open the ionosphere reference. Why is it not a sixth non-overlapping thermal layer? Which geophysical measurements could it affect?
Boundary reference table
| Boundary | Approximate location |
|---|---|
| Moho | Base of crust; varies with location |
| 410 / 660 km transitions | Mantle mineral phase changes |
| Gutenberg boundary | 2,891 km depth |
| Inner-core boundary | 5,150 km depth |
| Tropopause | ~8–18 km altitude; varies |
| Stratopause / mesopause | ~50 / 85 km altitude |
| Exobase | ~500–1,000 km altitude; varies |