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Earth is the third planet from the Sun and the only astronomical object known to harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all of Earth's water is contained in its global ocean, covering 70.8% of Earth's crust.
The history of Earth is divided into four great eons, starting 4,540 mya with the formation of the planet. Each eon saw the most significant changes in Earth's composition, climate and life. Each eon is subsequently divided into eras, which in turn are divided into periods, which are further divided into epochs. Eon.
The geological history of the Earth follows the major geological events in Earth's past based on the geological 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 ...
720,000 km/h (450,000 mi/h) [10] Orbital period. ~230 million years [10] The Solar System[d] is the gravitationally bound system of the Sun and the objects that orbit it. [11] It was formed about 4.6 billion years ago when a dense region of a molecular cloud collapsed, forming the Sun and a protoplanetary disc.
A globe is a spherical model of Earth, of some other celestial body, or of the celestial sphere. Globes serve purposes similar to maps, but, unlike maps, they do not distort the surface that they portray except to scale it down. A model globe of Earth is called a terrestrial globe. A model globe of the celestial sphere is called a celestial globe.
Main article: Solar System. According to the IAU definition, there are eight planets in the Solar System, which are (in increasing distance from the Sun):[2]Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Jupiter is the largest, at 318 Earth masses, whereas Mercury is the smallest, at 0.055 Earth masses.
e. Geography (from Ancient Greek γεωγραφία geōgraphía; combining gê 'Earth' and gráphō 'write') is the study of the lands, features, inhabitants, and phenomena of Earth. [1] Geography is an all-encompassing discipline that seeks an understanding of Earth and its human and natural complexities —not merely where objects are, but ...
Land is often defined as the solid, dry surface of Earth. [1] The word land may also collectively refer the collective natural resources of Earth, [2] including its land cover, rivers, shallow lakes, its biosphere, the lowest layer of the atmosphere (troposphere), groundwater reserves, and the physical results of human activity on land, such as architecture and agriculture. [3]