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Internal structure of Earth. Geological cross section of Earth, showing the different layers of the interior. The internal structure of Earth are the layers of the Earth, excluding its atmosphere and hydrosphere. The structure consists of an outer silicate solid crust, a highly viscous asthenosphere, and solid mantle, a liquid outer core whose ...
- Overview
- Inside the Earth
- River of Rock
Learn about the layers inside the Earth, inaccessible to humans.
The Earth's interior is composed of four layers, three solid and one liquid—not magma but molten metal, nearly as hot as the surface of the sun.
The deepest layer is a solid iron ball, about 1,500 miles (2,400 kilometers) in diameter. Although this inner core is white hot, the pressure is so high the iron cannot melt.
The iron isn't pure—scientists believe it contains sulfur and nickel, plus smaller amounts of other elements. Estimates of its temperature vary, but it is probably somewhere between 9,000 and 13,000 degrees Fahrenheit (5,000 and 7,000 degrees Celsius).
Above the inner core is the outer core, a shell of liquid iron. This layer is cooler but still very hot, perhaps 7,200 to 9,000 degrees Fahrenheit (4,000 to 5,000 degrees Celsius). It too is composed mostly of iron, plus substantial amounts of sulfur and nickel. It creates the Earth's magnetic field and is about 1,400 miles (2,300 kilometers) thick.
The next layer is the mantle. Many people think of this as lava, but it's actually rock. The rock is so hot, however, that it flows under pressure, like road tar. This creates very slow-moving currents as hot rock rises from the depths and cooler rock descends.
The mantle is about 1,800 miles (2,900 kilometers) thick and appears to be divided into two layers: the upper mantle and the lower mantle. The boundary between the two lies about 465 miles (750 kilometers) beneath the Earth's surface.
The crust is the outermost layer of the Earth. It is the familiar landscape on which we live: rocks, soil, and seabed. It ranges from about five miles (eight kilometers) thick beneath the oceans to an average of 25 miles (40 kilometers) thick beneath the continents.
Currents within the mantle have broken the crust into blocks, called plates, which slowly move around, colliding to build mountains or rifting apart to form new seafloor.
Continents are composed of relatively light blocks that float high on the mantle, like gigantic, slow-moving icebergs. Seafloor is made of a denser rock called basalt, which presses deeper into the mantle, producing basins that can fill with water.
Except in the crust, the interior of the Earth cannot be studied by drilling holes to take samples. Instead, scientists map the interior by watching how seismic waves from earthquakes are bent, reflected, sped up, or delayed by the various layers.
Oct 9, 2023 · Planet Earth is broadly composed of a crust, mantle and core. The crust hosts all known life, but it's merely Earth's outer casing, accounting for only 1% of the planet's total volume. The mantle ...
- Patrick Pester
Apr 23, 2018 · Isaac Newton gave a name to the concept of gravity and and discovered that gravity is influenced by density. He was the first to calculate the mass of the earth. Using gravity measurements in combination with Earth's mass, scientists determined that the interior of the Earth must be denser than the crust. Comparing rocks' density of 3 grams per ...
- Kimberly Yavorski
Dec 8, 2023 · 1. Generation of Earth’s Magnetic Field: Earth’s magnetic field is primarily generated by the movement of molten iron and nickel in the outer core of the planet. This process is known as the geodynamo. The geodynamo is driven by the heat generated from the decay of radioactive isotopes in the Earth’s interior and the cooling of the core. 2.
2 days ago · Earth - Core, Mantle, Crust: More than 90 percent of Earth’s mass is composed of iron, oxygen, silicon, and magnesium, elements that can form the crystalline minerals known as silicates. Nevertheless, in chemical and mineralogical composition, as in physical properties, Earth is far from homogeneous. Apart from the superficial lateral differences near the surface (i.e., in the compositions ...
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Apr 30, 2023 · Earth's interior is gradually cooling over time. As it cools, the liquid outer core crystallizes and becomes part of the solid inner core. Remarkably, the inner core "grows" by about 0.039 inches ...
