What is the external structure of the Earth? It has been known for more than 2000 years that the Earth is round Maximilian Philipp Jersey , but we were able to actually see this much later only when we flew into space. The knowledge why we do not fall off from the Earth is much more recent. A journey as described by author Jules Verne in his book Journey to the Center of the Earth was, after all, impossible. Only one thing was known: the Earth is made up of soil, rocks Matthias Ginter Jersey , and water. Today, we know that the Earth is also surrounded by an air cover called the atmosphere.
What is the internal structure of the Earth? Like an onion, the Earth has several layers. The outermost layer, the Earth鈥檚 crust Mario Gotze Jersey , has an average depth of about 40 km. As compared with the diameter of the Earth, which is around 12,700 km, the Earth鈥檚 c rust is very small. It is primarily made up of solid rocks. Below the crust is the mantle Marco Reus Jersey , reaching to a depth of about 2900 km. Due to the heat inside the Earth, th mantle consists of solid and molten rocks. Below the mantle is the core, made up of iron and nickel. The deeper one travels inside the Earth, the hotter it is. The temperature in the core is between 4000 and 5000 degree celcius.
How did we discover that the Earth is round? About 3000 years ago people believed that the Earth was flat. But people wondered why ships disappeared at the horizon. Sailors too returned from journeys and were proof that ships did not fall off the edge of the Earth. The simplest explanation was: the Earth must be round. The final proof came in the year 1522 after the expedition of Ferdinand Magellan Marcel Schmelzer Jersey , who was the first to sail around the Earth.
Why do we not fall off from the Earth? Gravity is the force of the Earth that attracts every object towards itself. From our perspective this force always acts downwards. For a long time people did not believe that the Earth is round because then the people 鈥榰nderneath鈥?the sphere would have actually fallen down. In 1687, a physicist , Issac Newton, proved that the force of gravity always acts towards the centre of the Earth. On the Earth Marc Bartra Jersey , the force of gravitation always acts 鈥榙ownwards鈥?irrespective of Eskimos in the Arctic region, people in Europe or inhabitants of Australia.
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Why Do you Need a North Shore Property Management Company? Home Business Articles | October 12, 2012 Property investors couldn?t possibly manage their realty or property investments on their own especially if they have multiple properties spread in many areas. The most viable option for them is to hi...
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