Structure of the Earth || Scientific FS
Structure of the Earth
What is the shape of the Earth?
The Earth is shaped like an oblate spheroid - a rounded figure with a bulge around the equator. The rotation of the Earth creates the equatorial bulge so that the diameter at the equator is 43 km larger than that measured between the poles.
What is the Earth made up of?
The Earth is made up of many different layers. Some of these layers are molten and some are solid. The Earth's outermost layer is composed of tectonic plates in relative motion. The motion of these plates is responsible for the emergence of mountains, volcanoes, and earthquakes. The composition of the Earth is 34.6% Iron, 29.5% Oxygen, 15.2% Silicon, 12.7% Magnesium, 2.4% Nickel, 1.9% Sulfur, 1.5% Calcium, 1.4% Aliminium, and other elements less than 1%.
What are the different layers of the Earth called?
The outermost rocky layer of the Earth is called the 'crust' and is composed mainly of alumino-silicates. It is a very thin layer - its thickness in relation to the Earth is about the same as the skin of an apple. The crust comprises the continents and ocean basins. The layer underneath the crust is called the 'mantle' and is composed mainly of ferromagnesian silicates. The mantle is where most of the internal heat of the Earth is located. The innermost layer is called the 'core' and is composed mainly of iron and nickel.
Why is the innermost layer composed of iron?
Most of the molecules that smashed together to make the Earth were iron. The smashing together released a lot of heat, which continuously kept the iron in a melted form. Iron is heavier than most other metals, so it sank to the center of the Earth, while lighter molecules like silicon and carbon rose to the top.
What are the tectonic plates?
The irregularly shaped huge slabs of rocks that float across the surface of the Earth are called tectonic plates. These are pieces of the Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around 100 km (62 miles) thick and consist of two principal types of material: oceanic crust (also called sima from silicon and magnesium) and continental crust (sial from silicon and aluminum). These plates constantly move around the surface of the Earth.
How many plates are there on the surface of our planet?
There are six primary plates and eight secondary plates comprising the bulk of our planet's surface. The primary plates are the African Plate, Antarctic plate, Eurasian Plate, Indo-Australian Plate, North American Plate, Pacific Plate, and South American Plate. The secondary plates are Arabian Plate, Caribbean Plate, Cocos Plate, Indian Plate, Juan de Duca Plate, Nazca Plate, Philippine Sea Plate, and Scotia Plate, Apart from these, there are some tertiary plates and microplates, which are believed to be dwindling remains of much larger ancient plates.
What is plate tectonic theory?
Plate tectonic theory scientifically describes the large-scale motions of the Earth's lithosphere. When the floating plates spread apart, it is called a 'spreading center'. When they are moving together, it is called a 'subduction zone'. When they are forced together, it is called a 'zone of convergence'.
Why is plate tectonics important?
The Earth is the only planet in the solar system with a crust of tectonic plates floating on top of a magma interior. Over time, plate tectonics pull carbon and other remnants of life back into the interior of the Earth, where they are recycled. Without plate tectonics, there would be no way to recycle the carbon, and our planet would overheat and end up hot and barren like Venus.
What are the five parts [spheres] of the Earth System?
The five parts of the Earth system are:
- Atmosphere - extends up from the surface for several hundred kilometers; the lowest part is home to clouds and weather.
- Biosphere - the life zone of the Earth; includes all living things.
- Geosphere - Extends from the surface to the core; includes all minerals, rocks, molten rock, sediments, and soils.
- Hydrosphere - includes the oceans, rivers, lakes, streams, groundwater, and water vapor.
- Cryosphere - the frozen part of the Earth system; includes snow, glaciers, and sea ice.
What is the Earth's atmospheric content?
The Earth's atmosphere contains a layer of gases retained by the planet's gravity. Air is the name given to the atmosphere used in breathing and photosynthesis. Dry air contains roughly (by volume) 78% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%.
How does the atmosphere help us?
The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night.
What is the greenhouse effect?
The greenhouse effect is a process, by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone.
What is the magnetosphere?
A magnetosphere is a region surrounding a planet where the planet's magnetic field dominates. The flowing metal in our planet helps create a large magnetic field, which prevents the harmful solar winds from hitting the Earth. The Earth's magnetic field reached 36,000 miles into space.
As we go deeper and deeper into the Earth, the temperature and pressure rise; the temperature at the core is believed to be an incredible 5000-6000 C.
The ratio of land and water on the Earth's surface is 29.2% : 70.8%. Approximately 97% of the Earth's water is seawater, and only 3% is freshwater.
Our planet is located in the perfect place for maintaining liquid water. If it were any closer to or farther from the Sun, all the water would either boil away or freeze.
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