QUESTIONS 1. a) The earth's inner core is just a few hundreds of degrees less than the temperature of the Sun: about 5200 degrees Celsius versus about 6000 Degrees Celsius. With that much heat in the centre of the earth, why is it still possible for life to exist on the surface of the earth? b) How is the heat in the earth's centre able to melt the outer core but not the inner core? 2). a). Describe the Goldsmith Classification of element. b). Describe how Goldsmith rules are used to classify Elements. c). Describe how the bonding types and magma differentiation aids in the distribution of trace elements in the Earth
1) The very high temperature inside the Earth can be attributed to its formation. The inner core temperature of Earth is 5200 degree Celsius and the surface temperature of Sun is around 6000 degree Celsius. Although Earth's center and Sun's outer surface has comparable temperature, it does not mean that Earth can be a star or there is life possible outside the Sun. The scenario of Earth and Sun is totally different because of the simple logic that Earth is a planet and Sun is a star. Earth is formed from the solar nebula 4.6 billion years ago.
(a) The source of heat inside Earth can be from the infalling materials during its formation and also the decay of radioactive elements which is still goin on inside the core. Later, planet Earth has gone through planetary development stages such as differentiation, cratering, flooding and slow surface evolution. The Earth evolved geographically unlike Sun.
Sun is a star. In a star, continuous fission and fusion reactions take place which ejects large amount of energy. From the core to the surface, conduction, convection and radiation take place and the heat is continuously transferred, Sun is in liquid or molten state from its core to the surface.
But in the case of Earth, radioactive decay takes place at the inner solid core, which is surrounded by the outer liquid core. Above the outer core, there is semi-molten mantle and above that there exists a solid thin crust. As we go from the core to the crust or the surface, the temperature and pressure drops down to an optimum, where life can grow.
(b) It is interesting to know that although the inner core has temperature that is close to the surface temperature of Sun, the inner core still remains in the solid phase and not liquid phase. The inner solid core is composed of iron. Because of the extreme temperature, the outer core is liquid. But under tremendous pressure, the crystallized iron core of Earth cannot vaporize. This high pressure raises the melting point so high that the material cannot melt. This is why the inner core remains in the solid phase.
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