The outer core of Earth is a fluid shell composed primarily of liquid iron with a significant fraction of nickel and lighter elements (e.g., S, O, Si), extending from the base of the mantle at ~2,890 km depth to the solid inner core at ~5,150 km. Its temperature and pressure conditions exceed the melting point of core alloys, maintaining a convecting metallic liquid that efficiently conducts electricity. This convection, strongly influenced by Earth’s rotation and compositional buoyancy from inner-core solidification, drives the geodynamo that generates and sustains Earth’s global magnetic field.
With modern seismic tomography, Earth scientists have discovered that above Earth's core-mantle boundary (CMB), about 2,900 kilometers beneath our feet, there is a thin layer about 300 kilometers thick with remarkable structural ...
Earth Sciences
Dec 23, 2025
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Scientists have discovered that Mars has an interior structure similar to Earth's. Results from NASA's InSight mission suggest that the red planet has a solid inner core surrounded by a liquid outer core, potentially resolving ...
Planetary Sciences
Sep 7, 2025
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A study by researchers at the University of Oxford, University of Leeds, and University College London has identified a new constraint on the chemistry of Earth's core, by showing how it was able to crystallize millions of ...
Earth Sciences
Sep 4, 2025
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Earth is fortunate in having a magnetic field: it protects the planet and its life from harmful cosmic radiation. Other planets in our solar system—such as Mars—are constantly bombarded by charged particles that make ...
Planetary Sciences
Jul 30, 2025
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Earth's largest gold reserves are not kept inside Fort Knox, the United States Bullion Depository. In fact, they are hidden much deeper in the ground than one would expect. More than 99.999% of Earth's stores of gold and ...
Earth Sciences
May 22, 2025
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Earth's nearest neighboring body in the solar system is its moon, yet to date, humans have physically explored just 5% of its surface. It wasn't until 2023—building on Apollo-era data and more detailed studies made in 2011–2012 ...
Planetary Sciences
Dec 19, 2024
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Is there something strange and alien confined deep inside the Earth? Is it trying to break free and escape into the heavens? No, of course not.
Planetary Sciences
Nov 1, 2024
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