Inside the Earth

Artwork showing Earth's internal layers

Geologists study how earthquake waves travel through the planet to understand its inner structure. They are still refining their interpretations, but the evidence suggests the following:

Earth has a solid, dense, iron-rich inner core surrounded by a fluid outer core, also mainly iron.

The next layer out, the mantle, is split into the lower and upper mantle. Though it is solid rock, parts of the mantle slowly deform. Hotter rock rises and cooler rock sinks through convection, driving the movement of the Earth's plates.

Above the mantle lies the crust upon which we live. The lithosphere incorporates the crust and part of the upper mantle.

Image: Artwork showing the Earth's internal layers (credit: Jose Antonio Peñas/SPL)

Introduction

Artwork showing Earth's internal layers Inside the Earth

TV clips (5)

Inside the Earth

The interior structure of the Earth is layered in spherical shells, like an onion. These layers can be defined by either their chemical or their rheological properties. Earth has an outer silicate solid crust, a highly viscous mantle, a liquid outer core that is much less viscous than the mantle, and a solid inner core. Scientific understanding of Earth's internal structure is based on observations of topography and bathymetry, observations of rock in outcrop, samples brought to the surface from greater depths by volcanic activity, analysis of the seismic waves that pass through Earth, measurements of the gravity field of Earth, and experiments with crystalline solids at pressures and temperatures characteristic of Earth's deep interior.

Read more at Wikipedia

This entry is from Wikipedia, the user-contributed encyclopedia. If you find the content in the 'About' section factually incorrect, defamatory or highly offensive you can edit this article at Wikipedia.