Mother Earth
- Third planet from the Sun
- Age : 4.5 Billion Years
- Its Only Satellite : Moon
- Revolution Time around sun : 365.26 days (Earth Year)
- Axis : tilted with respect to Orbital plane
- Rotation around axis cause : Seasons
- Ocean Tides :Gravitation b/w Earth & Moon
- Largest Terrestrial planet, densest planet in solar system
- Lithosphere : divided into several rigid tectonic plates
- Water cover : 71 % (mostly Oceans)
- Land cover : 29% (continents, islands, etc)
- Over 99% of species on earth ever lived are Extinct
- Over 7.6 billion humans live on earth
- World has over 200 Sovereign states
- The word Earth derived from an Old English noun most often spelled eorðe
- Earth's atmosphere and oceans were formed by volcanic activity and outgassing.
- Shape of Earth : Oblate Spheroidal
- due to rotation, earth is flattened at poles and bulged around equator
- diameter of Equator is 43 km(27 miles) larger at that of pole
- the point on the surface farthest from Earth's center of mass is the summit of the equatorial Chimborazo volcano in Ecuador
- The average diameter of the reference spheroid is 12,742 kilometres (7,918 mi)
- the geoid is the surface of gravitational equipotential at mean sea level.
- Earth's mass is approximately 5.97×1024 kg
- It is composed mostly : -
- iron (32.1%),
- oxygen (30.1%),
- silicon (15.1%),
- magnesium(13.9%),
- sulfur (2.9%),
- nickel (1.8%),
- calcium (1.5%), and
- aluminium (1.4%)
- Over 99% of the crust is composed of 11 oxides, principally silica, alumina, iron oxides, lime, magnesia, potash, and soda
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