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The internal structure of the outer planets. A planetary core consists of the innermost layers of a planet. [1] Cores may be entirely liquid, or a mixture of solid and liquid layers as is the case in the Earth. [2] In the Solar System, core sizes range from about 20% (the Moon) to 85% of a planet's radius .
Schematic illustration of the internal structure of the Moon. Several lines of evidence imply that the lunar core is small, with a radius of about 350 km or less. [5] The diameter of the lunar core is only about 20% the diameter of the Moon itself, in contrast to about 50% as is the case for most other terrestrial bodies.
The terrestrial planets all have roughly the same structure: a central metallic core, mostly iron, with a surrounding silicate mantle. The Moon is similar, but lacks a substantial iron core. [ 1 ] Three of the four solar terrestrial planets (Venus, Earth, and Mars) have substantial atmospheres ; all have impact craters and tectonic surface ...
A theoretical class of planets, composed of a metal core surrounded by primarily carbon-based minerals. They may be considered a type of terrestrial planet if the metal content dominates. The Solar System contains no carbon planets but does have carbonaceous asteroids, such as Ceres and Hygiea. It is unknown if Ceres has a rocky or metallic core.
Mass and moment of inertia constraints indicate that the Moon likely has an iron core that is less than about 450 km in radius. Studies of the Moon's physical librations (small perturbations to its rotation) furthermore indicate that the core is still molten. Most planetary bodies and moons have iron cores that are about half the size of the body.
The Moon's density is substantially less than that of Earth, due to its lack of a large iron core. [3] On Earth , physical and chemical differentiation processes led to a crustal density of approximately 2700 kg/m 3 compared to the 3400 kg/m 3 density of the compositionally different mantle just below, and the average density of the planet as a ...
The diameter of this colossal disk is roughly 3,300 times the distance between Earth and the sun, with enough gas and dust to form super-sized planets in far-flung orbits, the U.S. and German ...
Internal heat is the heat source from the interior of celestial objects, such as stars, brown dwarfs, planets, moons, dwarf planets, and (in the early history of the Solar System) even asteroids such as Vesta, resulting from contraction caused by gravity (the Kelvin–Helmholtz mechanism), nuclear fusion, tidal heating, core solidification (heat of fusion released as molten core material ...