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|Earth, the third planet from the sun.|
|Other names||Terra (Tellus), Gaia|
|Semimajor axis||149,598,261 km (1.00000261 AU)|
|Orbital Period||365 days (1 earth year)|
|Average orbital speed||66,610 mph (107,200 km/h)|
|Surface area||510,072,000 km|
|Surface temperature (min)||184 K (-89.2 °C, -128.56 °F)|
|Surface temperature (avg)||288 K (15 °C. 59 °F)|
|Surface temperature (mean)||288 K (15 °C. 59 °F)|
|Surface temperature (max)||330 K (56.7 °C, 134.02 °F)|
|Population||7 billion +|
|Surface Pressure||101.325 kPa|
|Composition|| 78.08% nitrogen
20.95% oxygen 0.93% argon 0.039% carbon dioxide
|Habitable||Yes, in the Habitable zone and Habitabed by humans|
Earth is approximately 4.54 billion years old, and life began appearing on it during the first billion years of it's life. The physical properties of the Earth, along with the geological location, history, and orbit, have allowed life to continue living on Earth. Estimates on how long the planet will continue to hold life are around 500,000 years, to as long as 2.3 billion years.
Earth is home to millions of species of life, including humans. The mineral resources of Earth, and the other products of the biosphere, contribute resources that are used to support a global human population. These inhabitants are grouped into about 200 countries, whom interact with diplomacy, travel, trade, military action, amongst other things.
The modern English noun earth developed from the Middle English word erthe (dating to 1137), which derived from the Old English word eorthe, dating from before 725, which in itself derived from Proto-Germanic *erthō.
In general English usage, the name earth can be capitalized, or spelled in lowercase interchangeably, either when used absolutely or prefixed with "the" (e.g, Earth, the Earth, earth, or the earth). Many deliberately spell the name of the planet with a capital, both as "Earth" or "the Earth". This is to distinguish it as a proper noun, distinct from the senses of the term as a mass noun or verb (e.g. referring to soil, the ground, earthing in the electrical sense, etc.).
Composition and structureEdit
Future of the EarthEdit
The future of Earth is mostly tied to the sun. Because of the steady accumulation of helium at the Sun's core, the star's total luminosity will slowly increase. Climate models show and indicate that the rise in radiation reaching the Earth is likely to have dire consequences, such as the loss of the oceans.
The Earth's increasing surface temperature will accelerate the inorganic CO2 cycle, reducing its concentration to levels lethally low for plants (10 ppm for C4 photosynthesis) in approximately 500-900 million years. The lack of vegetation will result in the loss of oxygen, so all animal life will become extinct in several million years. After a billion years, all of Earth's oceans will disappear, and the average Earth surface temperature will be 343 K (70 °C, 159 °F).
The Sun, part of it's evolution, will become a red giant in about 5 billion years. Models predict that the Sun will expand out to about 250 times its present radius. Earth's fate, however, is less clear. Since the Sun will become a Red Giant, the Sun will lose roughly 30% of its mass, so without tidal effects, the Earth will move into an orbit, around 250,000,000 km from the Sun, when the Sun reaches it's maximum radius. Therefor, it was initially thought that Earth is likely to survive, however, most, if not all of it's remaining life will be destroyed as the Sun's increased luminosity (peaking at about 5,000 times its present level). A 2008 simulation indicates that, the Earth's orbit will decay due to tidal effects and drag, causing it to enter the red giant Sun's atmosphere and be vaporized. After this, the Sun's core will collapse into a white dwarf. The matter that once made up the Earth will be released into interstellar space, where it may one day become incorporated into a new generation of planets and other celestial bodies.