How have we determined whut the inside of the earth looks like?
There are two major types of seismic waves: Compressional (called ‘P’ waves) and Shear (called ‘S’ waves). Shear waves cannot travel through a fluid. When an earthquake occurs seismographs worldwide record the disturbance. Some of the seismographs, however, don’t receive any of the S-waves, because the seismographs are on the side of Earth opposite the earthquake. The only reason such a “shadow” would occur is if there was a fluid (liquid or gas, but gas is discounted as will be shown later) core inside the Earth. The size of the shadow zone can be related to the size of the liquid core, by taking into account the bending of the seismic waves by changes in density of the rock layers inside the Earth. So, the presence and size of the liquid core can be determined. Theoretical considerations require that there is a solid core in the very center, surrounded by a liquid core. The same types of waves, only those that are created artificially, are used to “look at” thinner layers of rock in
Scientist believe this because of pulses that they send through the earth, and how it travels. Like everything in science it’s only a theory. There are many different vies about like the tectonic plates, there is actually a scientist that thinks the world is expanding, and there is a lot of information supporting it, however people already believe the plates are moving, and changing one peace of science will change many more because it is all so closely related. Therefore people are afraid of change. Wow off topic much.
