The Earth’s Interior Layers – Part 3, The Outer Core

Are you tired yet? You’ve been digging a long time. Now that you have passed through the mantle, you are at the edge of the outer core. Can you swim? I hope so because this 1,380 mile thick layer is liquid! That’s right; the core is so hot that the outer layer is molten. The liquid outer core is made of iron and nickel and scientists believe that electric currents within this layer control the Earth’s magnetic field.

Another seismic change occurs at the boundary between the mantle and the core. This transition zone is called the core-mantle boundary, or the Gutenberg discontinuity. Some seismic waves disappear at this boundary, which indicates that the outer core is liquid. The temperature of the outer core material is approximately 4,400°C and increases as it reaches the inner core to nearly 6,100°C. Whew! Now that’s HOT!!


Up next: The Inner Core

Images Courtesy NASA
Crystal at the Center of the Earth; Ronald Cohen and Lars Stixrude; Carnegie Institute of Washington
Earth’s Interior; J. Louie; University of Nevada Reno; 1996
Structure of the Interior of the Earth; Lisa Gardiner; National Earth Science Teacher Association; 2010
The Interior of the Earth; Eugene C. Robertson; USGS



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