Earth create 4.54 billion years ago, and liveliness appeared on its erupt inside wizard billion years.[21] The planet is home to millions of species, including humans.[22] Earths biosphere has significantly altered the atmosphere and other abiotic conditions on the planet, enabling the proliferation of aerobic organisms as well as the formation of the ozone layer which, together with Earths magnetic field, blocks harmful solar radiation, permitting life on land.[23] The physical properties of the Earth, as well as its geological history and orbit, grant allowed life to persist during this period. Estimates on how much retentiveer the planet give to be able to continue to support life persona from a mere 500 million years, to as long as 2.3 billion years.[24][25][26]
Earths out surface is divided into some(prenominal) rigid segments, or tectonic plates, that migrate across the surface over periods of many millions of years.
About 71% of the surface is cover by salt water oceans, with the remainder consisting of continents and islands which together have many lakes and other sources of water that contribute to the hydrosphere. Earths poles are by and large covered with solid ice (Antarctic ice sheet) or sea ice (Arctic ice cap). The planets interior remains active, with a thickly layer of relatively solid mantle, a liquid outer core that generates a magnetic field, and a solid iron out inner core.
Earth interacts with other objects in space, especially the Sun and the Moon. At present, Earth orbits the Sun once every 366.26 times it rotates about its own axis, which is equal to 365.26 solar days, or one sidereal year.[note 7] The Earths axis of rotation is tilted 23.4° away from the...If you exigency to get a full essay, order it on our website: Orderessay
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