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Earth orbits the Sun, making Earth the third-closest planet to the Sun and part of the inner Solar System. Earth's average orbital distance is about 150 million km (93 million mi), which is the basis for the astronomical unit (AU) and is equal to roughly 8.3 light minutes or 380 times Earth's distance to the Moon.
Terrestrial planets have numerous similarities to dwarf planets (objects like Pluto), which also have a solid surface, but are primarily composed of icy materials. During the formation of the Solar System, there were probably many more ( planetesimals ), but they have all merged with or been destroyed by the four remaining worlds in the solar ...
A terrestrial planet, tellurian 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 .
Superior planets: Planets whose orbits lie outside the orbit of Earth. [nb 1] Jupiter, Saturn, Uranus and Neptune: Trojan planet: A planet co-orbiting with another planet. The discovery of a pair of co-orbital exoplanets has been reported, but later retracted. [3] One possibility for the habitable zone is a trojan planet of a gas giant close to ...
Earth's inner core is the innermost geologic layer of the planet Earth. It is primarily a solid ball with a radius of about 1,220 km (760 mi), which is about 20% of Earth's radius or 70% of the Moon's radius. [1] [2] There are no samples of the core accessible for direct measurement, as there are for Earth's mantle. [3]
"Inferior planet" refers to Mercury and Venus, which are closer to the Sun than Earth is. "Superior planet" refers to Mars, Jupiter, Saturn, Uranus, and Neptune (the latter two added later), which are further from the Sun than Earth is. The terms are sometimes used more generally; for example, Earth is an inferior planet relative to Mars.
Earth formed approximately 4.6 billion years ago from a disk of dust and gas orbiting the newly formed Sun. It formed via accretion, where planetesimals and other smaller rocky bodies collided and stuck, gradually growing into a planet. This process generated an enormous amount of heat, which caused early Earth to melt completely.
The geological history of Earth follows the major geological events in Earth's past based on the geologic time scale, a system of chronological measurement based on the study of the planet's rock layers (stratigraphy). Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left over from ...