A deep cutaway cannot be checked by drilling through the whole planet. Scientists infer structure from seismic waves, gravity, magnetism and experiments. Different materials and physical states affect wave behaviour. The diagram uses approximate spherical boundaries; its selected continental crust thickness is an example rather than one worldwide constant.
Earth and geology · Discover & try
What is inside Earth?
Reading level 4 of 5 · FluentChange
Word help
Mantle
The thick layer of mostly solid rock below the crust.
Outer core
Earth’s liquid, metal-rich layer surrounding the inner core.
Depth
Distance below the surface, distinct from distance from the centre.
Watch · Try · Explain
See how it works
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Approximate radial boundaries; crust thickness varies and its thin edge is highlighted for visibility.
What to look for
- Compare depth with radius.
- Look for the liquid layer.
- Notice how thin the crust is.
Explain what you noticed
A diagram colours the mantle red. Does that prove it is a global liquid magma ocean?
Keep this idea: Earth’s mantle is mostly solid rock; the outer core is liquid and the inner core solid.
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