Cores
Listosphere
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Athenosphere/Mantle
The region below the lithosphere,variously estimated as being from fifty to several hundred miles thick, in which the rock is less rigid than that above and below but rigid enough to transmit transverse seismic waves. Asthenosphere is also a zone of Earth’s mantle lying beneath the lithosphereand believed to be much hotter and more fluid than the lithosphere.
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Inner Core/Outer CoreInner Core
The inner core was discovered by Inge Lehmann in 1929, using seismology. Lehmann was studying a large New Zealand earthquake. An earthquake makes vibrations which move through the inside of the Earth. The vibrations Lehmann studied seemed to be moving across something solid in the center of the planet. She called this the inner core. She wrote about it for many years, but it was not proved to exist until 1970. Outer Core It's a good thing that the outer core is liquid. This is because it's responsible for the Earth's magnetic field. Every day the Earth is bombarded by charged particles and radiation from the Sun, in quantities that would be extremely dangerous to humans and could give us all cancer. But thanks to the Earth's magnetic field, most of these particles are pushed out of the way and funneled to the North and South Poles. There, they enter the Earth safely, creating a beautiful light display called the Aurora Borealis (or 'northern lights'). |