- Our Place In Space -

• We can start describing earth when its place in Solar System
• Earth has been called "The Blue Planet"
• The Equator is the imaginary line around the earth surface
• Earth diameter measures 12,576 kilometers at the Equator and 12,713 kilometers to Pole
• A Plain is a broad flat area It is relatively low with respect to sea level.
• A moutain is a highland with relatively small summit area.
• A moutain range is a chain of moutains.
• A pricipal or major moutain range of a continet is refferd as cordillera
• A hill is a highland that is less massive than a moutain.
• A plateau is a highland with a top that is broad and flat like a plain
• A volcano is a hill or moutain formed around weak area
• a valley is relatively long and flat area
• a swamp is a wetland saturated with water It maybe partially or periodically coverd with water . The same is true with Marsh
• A Delta is a deposit of sand and soil at the moutain of some rivers.
• A Penisula is a peice of land nearly surrounded by water. It may or may not be connected to the mainland by a narrow strip of land called isthmus
• A Cay is a coral reef or sand bank
• Earth makes one complete rotation on its axis every 23 hours , 56 minutes and 4.09 seconds this period usually rounded 24 hours defines the length of one earth day
• Earth completes one revoulution around the sun every 365 1/4 days this period defines the length of one earth year
• The imaginary line in which seperates the zones of day and night is called twilight circle
• The changes in orrientation of earth axis with respect to the sun , as it travels around the sun, gives rise to phenomenon of regular changing of seasons
• Earth day - is the time it takes for earth to make one complete rotation on its axis, which is roundes about 24 hours
• Earth year is the time it takes for earth to complete one revoloution around the sun every 365 1/4 days