Earth: Shape and Size: Shape, Diameter, Geoid and Mass, Location on Earth

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Earth: Shape and Size

  • Shape: Spheroid. (Oblate spheroid or oblate ellipsoid)

  • Diameter: Equatorial – 12757 km (7927 miles); Polar – 12715 km (7901 miles)

  • Geoid: Imaginary shape of the earth where sea level surface of the oceans is extended to the continents to form continuous figure.

  • Mass: 5.976*1024 kg

  • Volume: 1.083*1024 litters

  • Mean density: 5.518 kg/litre

  • Total Surface Area: 509.7 million sq.km. Land – 148.4 million sq.km (29 pc). Water – 361.3 million sq. Km (71 pc)

  • Rotation: 23hrs 56 mins 4.09 sec

  • Revolution: 365 days, 6 hrs, 9 mins and 9.54 sec

  • Highest point: Mt Everest (8848 m asl)

  • Lowest point on land: Coast of Dead sea (399 m bsl)

  • Mean height of land: 756 m

  • Deepest point: Mariana trench (near Guam: 11033 m bsl)

  • Avg ocean depth: 3730 m

  • Earth’s Crust: Oxygen (46.6 pc), silicon (27.7 pc), Al (8.1 pc), Iron (5 pc), Ca (3.6 pc), Na (2.8 pc), K (2.6 pc), Mg ( 2 pc). Other elements (1.6 pc)

  • Hottest: Lut deserst, Iran (70.7 degreeC)(internet). Al Aiziyah, Libya (58 degree C)

  • Coldest: Vostok Station, Antarctica (-89.6 degree C)

  • Inclination on polar axis: 23 deg 26 min 50 sec

  • Orbital Speed: 29.8 km/s

  • Mean distance from sun: 149,598,500 km ( 1 AU).

  • Max distance: 152 million km (aphelion, July 2-5)

  • Min distance: 147 million km (perihelion, Jan 2-5)

Location on Earth

  • Latitude: Angle subtended by a point to the equatorial place. Lines of latitudes are called parallels.

  • Longitude: Distance east or west of the meridian of Greenwich.

  • Equator: Parallel of zero is called equator. It is the largest circle that can be drawn on earth.

  • Countries on Equator: (countries) Sao Tome and Principe, Gabon, Republic of Congo, Democratic Republic of Congo, Equador, Columbia, Brazil, Uganda, Kenya. Somalia, Indonesia. (water bodies) Atlantic Ocean, Gulf of Guinea, Indian Ocean, Gulf of Tomini, Halmahera Sea, Pacific Ocean.

  • Geographical Mile: One arc of the equator.

  • Tropic of Cancer: 23.5-degree North.

  • Countries on Tropic of Cancer: (countries)Mexico, Bahamas, Western Sahara, Mauritania, Mali, Algeria, Niger, Libya, Egypt, Saudi Arabia, UAE, Oman, India, Bangladesh, Myanmar, China, Vietnam, Taiwan; (water bodies) Red Sea, Arabian Sea, Indian Ocean, Taiwan Strait, Pacific Ocean, Gulf of California, Gulf of Mexico, Atlantic Ocean

  • Tropic of Capricon: 23.5-degree South

  • Countries on Tropic of Capricon: (countries) Chile, Argentina, Paraguay, Brazil, Namibia, Botswana, South Africa, Mozambique, Madagascar, Australia; (water bodies) Indian Ocean, Atlantic Ocean, Pacific Ocean

  • Arctic Circle: 66.5-degree North

  • Areas on Arctic Circle: (countries) Norway, Sweden, Finland, Russia, US-Alaska, Canada, Greenland, Iceland; (water bodies) Arctic ocean, White Sea, Kandalaksha Gulf, Gulf of Ob, Chukchi Sea, Kotzebue Sound, Norwegian Sea, Davis Strait, Greenland Sea.

  • Antarctic Circle: 66.5-degree South

  • Areas on Antarctic Circle: (land) Different regains on Antarctica are claimed by some countries – By this claim the circle passes through territories in Antarctica claimed by Australia, France, Argentina, Chile and United Kingdom; (water) Southern Ocean

  • The two tropics mark the limit of the zones at between which sun’s rays can be vertical at one time of the other. At tropics, sun rays are vertical once a year while in between the tropics twice a year.

  • Summer Solistice: Sun overhead Tropic of Cancer

  • Winter Solistice: Sun overhead Tropic of Capricon.

  • Greenwich: Prime meridian

  • Great circle: It is the largest circle that can be drawn on earth. Its plane passes through the centre of the earth. Navigators follow the great circle routes to minimize distance.

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