GEOLOGY - Earths Interior :: essays research papers fc

INTRODUCTIONFor millennia mankind has inhabited the third planet from the sun the planet that supports life and is know to us as Earth. Although there has been life on Earth for quite sometime, it is only in the past few centuries that man has come to learn about what makes up the midland of this planet. The English scientist, Isaac Newton, can be seen as a pioneer in regards to learning about the Earths interior, as he metrical from his studies of planets and the force of gravity, that the average density of the Earth is twice that of surface rocks and therefore that the Earths interior must be self-possessed of a much denser material. Our cognition of whats inside the Earth has improved immensely since Newtons time, but his estimate of the density remains essentially unchanged. So what is this new knowledge of the Earths interior? PRESENT KNOWLEDGEA round sphere with many social classs, all varying in thickness, each having its own colour and taste this is a description of a g ob-stopper and also bares a close resemblance to the internal structure of the Earth a sphere divided into three layers, differing in density, composition, strength, and state. The densest of these layers is the core, which is composed largely of metallic iron, with small amounts of nickel and other elements. The less dense mantle then covers this layer, being composed of magnesium and iron silicates. The outermost layer is that of the crust, it has the lowest density of all the layers and can be separated upgrade as its thickness varies greatly from place to place, with the difference being distinguished by land and sea and also its composition. For this reason the core is subdivided into the continental crust (average thickness 45km with a granitic composition) and the oceanic crust (average thickness 8km with a basaltic composition). Similarly the core can also be subdivided, but the difference is not one between compositions but one by physical state. The privileged core of th e Earth is solid iron this is because it is under such high pressure, so high that temperature has no bearing on its state. The outer core has a balance between temperature and pressure so its iron composition is in the molten state.Rock strength can also add further categorisation to the Earths interior, bringing in the sphere layers the mesosphere, asthenosphere, and lithosphere.