Internal Structure Of The Earth :: essays research papers

What is the evidence for our knowledge of the internal structure of the Earth?As we enter the twenty first century we are beginning to exact more and more about the composition of the Earth. Early predictions have throw up some rather strange and peculiar thoughts as to what is fashioning up our Earth, but now days scientists can be confident that the Earth is make up of what they think. As from experiments and other sources of schooling a picture to what is really down there is becoming a great deal clearer.So how do these scientists know that the Earths sections are do up of different compositions, and how do we know that the physical state of each level is what it is?The outmost layer of the Earth is the crust, this is what we stand on and covers the earth entirely. It is made up of many different rocks and minerals, we know that the composition of the Earths crust is generally the kindred due to the mines and boreholes that humans have made down into it. Mines that have been dug go down and still lend up valuable minerals that can be found just as close to the Earths surface. The deepest goes down around 3km into the earth, and the temperature is 70XC, the only(prenominal) way for miners to work is because of the air conditioning, and still the type of rock looks the same all around. Also boreholes that have been drilled as far as half way into the Earths crust bring up rocks that look very similar to the ones on the surface. So scientists can safely say that the Earth has a crust which is very similar in composition all the way down until the mantle is reached.When earthquakes happen they plead two types of swans P-waves and S-waves. Primary waves (p-waves) are the fastest waves, they travel away from a seismic event. Primary waves are longitudinal, they can travel through solids, liquids and gases. The thirdhand waves (s-waves) travel slower than the primary waves, and are traverse waves. This type of wave can only travel through solids. Mea suring these waves is called seismology.Scientists have know for a long time that the lava, which comes out from volcanoes when they erupt, was from the mantle. The asthenosphere is the probable source of more than basaltic magma, this is because the velocity in S-waves is slowed down and partially absorbed in the asthenosphere.