FACTS OF EARTH Objectives

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  Largest element found in earth crust is Silicon, second is Aluminum
  Polar diameter of earth is 7900 miles
  Equatorial diameter is 7927 miles = 12,756 km
  Earth’s polar diameter is shorter than the equatorial diameter by 43 km
  Distance of equator from either of poles is 10,002 km
  World is divided into 24 time zones
  Age of earth is 5 billion years
  Speed of earth in orbit around sun is 8.5 miles/sec = 1600 km/min = 29 km/sec
  Weight of earth is 6586 x 10 raise to 18 tons
  Earth has 46.6% oxygen and 27.7% silicon
  On 21st June, sun is vertically overhead the Tropic of Cancer
  The South Temperate zone lies between Capricorn and Antarctic circle
  At equator the duration of the day is 12 hours
  510 million square kilometers is the total surface area of the earth
  Sun is 400 times larger than the Moon.
  About 6 billion people living on the Earth.
  When are you most likely to see a penumbra: During an Eclipse
  At equator an object weights the least.
  A wind which reverses seasonally is Monsoon.
  Water is the most powerful source of erosion
  Tropic of cancer crosses Pakistan.

  Spring tides occur at new moon or at full moon.
  Neap tides occur at first and third quarters of the moon.
  Oceans are on average 4 km deep.
  Frozen water covers about 10% of the earth
  Solar eclipse occurs on new moon.
  Lunar eclipse occurs on full moon.
  The standard time of England is known as Greenwich Mean Time. T is local time of
Greenwich Observatory which on 0° longitude.
  Daylight saving time begun during WWI.
  There are three belts of calm viz: Doldrums, Tropic of Cancer & Tropic of Capricorn.
  Horn of Africa is Ethiopia, Djibouti and Somalia.
  Kimberley is associated with Diamonds.
  In Titusfills in Pennsylvania (US) is world’s first oil-well drilled.
  Thickness of earth crust 20 miles.
  Max height of cloud 20,000.
  Nitrogen gas found in atmosphere is 78%, oxygen is 21%
  Speed of electromagnet ways is 300000 km/sec
  The layer of earth in which we live is Troposphere
  The atmospheric layer closet to earth is Troposphere.
  Weather phenomenon take place in Troposphere
  Atmospheric layer ideal for flying is Troposphere
  Ionosphere reflects radio-waves back to earth
  Nimbostratus clouds bring a long steady rain
  Clouds found at highest altitude are Noctilucent
  Thickness of atmosphere around earth is 145 km
  Atmosphere maintains earth’s temperature
  % of insulation received by earth’s surface is 51%
  Atmospheric layers are divided into 4 parts
  Sun’s heat and energy reaches earth by Radiation
  Air is composed of 78% Nitrogen.
  21% Oxygen.
  1% Other gases.
  Planetary winds consist of doldrums, trace winds and westerlies.
               
  Troposphere is 10 km, Stratosphere is from 10 to 40 km, Mesosphere (Neutraspace) is from 40 to 80 km, Thermosphere (Ionosphere) is from 80 to 370 km and Exosphere (Heaviside) is beyond 370 km.
  Megnetosphere that lies beyond the Exosphere is not the part of atmosphere.
  3/4th of the air that envelops the earth is in troposphere.
  97% of the air is below the upper boundary of the stratosphere which is the maximum height that aircraft may reach with the support of air.
  Smog is when water vapour condenses around a particle of smoke
  Atmospheric temperature increases at higher altitudes due to convection
  Formaula of Ozone is O3
  CFCs are Chloro Fluoro Carbons
  Earth’s atmosphere is over 1000 km deep
  Biosphere is the sphere of life which covers all the three spheres i.e litho, hydro, atmosphere
  Ozone layer is found in Stratosphere.
  Climate is the average weather of a particular place over many years. Weather change

day to day, whereas climate remains same for years.
  Every seson, trees add a new ring of growth to their trunks
  Clouds are made of water droplets, ice, crystals, particles of dust and air
  Warm air can hold more water vapour than cold air
  The age of Earth is calculated as 4500 million years.
  Ozone is measured in percentage (chk)
  The amount of ozone in the atmosphere is expressed in ppm/ The amount of ozone in the atmosphere is expressed in ___dobson units (chk)
  Air is composed of nitrogen (78.08%),oxygen (20.95%),argon (0.94%) and carbon dioxide (0.03%).
  Nitrogen gas dominates the earth’s surface.
  Weathering takes place more quickly in warm, wet area than in cold and dry regions.
  An atmosphere is a blanket of gas that surrounds a plane. Earth’s atmosphere is over
1000 kilometers deep, but most of it is in the 30 kilometers closest to Earth.
  Weight of the air pushing on us is known as atmospheric pressure.
  Atmospheric pressure is equal to 14.73 lbs per sq. inch.
  Atmospheric pressure decreases with height.
  In nature the nitrogen of the atmosphere is made available for the plant growth through the activity of bacteria called nitrogen fixation of bacteria in roots of plants. Earthworms provide nitrogenous wastes.
  Ozone is found in stratosphere b/w 20 to 50 km.
  The tidal effect of Moon on the surface of Earth is less that that of Sun because Moon’s gravitational pull at Earth’s surface is less as compared to Sun’s gravitational pull. Tidal effect of sun is 146% of moon.
  Injurious ultraviolet radiations are mostly prevented from reaching the earth as these are absorbed mostly by Ionosphere.
  510 million square kilometers is the total surface area of the earth.
  At 7050 km per hour, Sun rotate on its axis.
  The northern polar lights are called Aurorae Borealis, and southern polar lights are called
Aurorae Australis.
  The pulsating universe theory explains the evolution of universe.
   

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