Search results
Results From The WOW.Com Content Network
A ring system is a disc or torus orbiting an astronomical object that is composed of solid material such as gas, dust, meteoroids, planetoids or moonlets and stellar objects. Ring systems are best known as planetary rings, common components of satellite systems around giant planets such as of Saturn, or circumplanetary disks.
A terrestrial planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate, rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, Venus, Earth and Mars. Among astronomers who use the geophysical definition of a planet, two or three ...
The four terrestrial planets Mercury, Venus, Earth and Mars. The four terrestrial or inner planets have dense, rocky compositions, few or no moons, and no ring systems. They are composed largely of refractory minerals such as silicates—which form their crusts and mantles—and metals such as iron and nickel which form their cores.
e. The geology of solar terrestrial planets mainly deals with the geological aspects of the four terrestrial planets of the Solar System – Mercury, Venus, Earth, and Mars – and one terrestrial dwarf planet: Ceres. Earth is the only terrestrial planet known to have an active hydrosphere. Terrestrial planets are substantially different from ...
There is evidence that the formation of the Solar System began about 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud. [ 1 ] Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a protoplanetary disk out of which the planets, moons, asteroids, and ...
Earth's interior, like that of the other terrestrial planets, is divided into layers by their chemical or physical (rheological) properties. The outer layer is a chemically distinct silicate solid crust, which is underlain by a highly viscous solid mantle. The crust is separated from the mantle by the Mohorovičić discontinuity. [130]
Planetary science. A geological map of the Sputnik Planitia basin on the dwarf planet Pluto. Analysis of planetary surfaces and surface features is a major component of planetary science. Planetary science (or more rarely, planetology) is the scientific study of planets (including Earth), celestial bodies (such as moons, asteroids, comets) and ...
Celestial spheres. The celestial spheres, or celestial orbs, were the fundamental entities of the cosmological models developed by Plato, Eudoxus, Aristotle, Ptolemy, Copernicus, and others. In these celestial models, the apparent motions of the fixed stars and planets are accounted for by treating them as embedded in rotating spheres made of ...