AT THE EARTH’S CORE (PDF)
The Geophysics of Planetary Evolution
Bruce Peret (1998)
Published in Reciprocity, Volume XXVII, № 1, page 9.
Very little is actually known about the Earth’s interior. Actual research is limited to what is pulled up from a scant few miles of the crust, by deep mines and drilling rigs. Volcanoes provide some additional insight as to the existence of a molten plastic-like layer between the crust and mantle known as the asthenosphere. However, the bulk of data beyond this point comes from the distant echoes of earthquakes, and the seismographic machines that plot their deviations as they traverse the depths of the Earth’s interior.
Figure 1: Planetary Interior
What seismology has discovered is that the Earth’s interior is composed of several layers of varying density and composition. The topmost being the crust, a 40-mile-thick layer of silicon, aluminum, and magnesium, cracked into large, “tectonic plates,” sitting on an 1800-mile thick layer of basalt known as the mantle, covering an 1200-mile thick, irregular sphere of molten iron comprising the outer core, and finally, a solid sphere some 1600 miles in diameter, of which very little is known—the inner core.
What goes on in the depths of the Earth is still a mystery. The farther down, the bigger the mystery. According to author Dougal Dixon, “The rules of conventional physics just do not apply to the Earth’s core.”1
There are also several planetary oddities that have stumped modern science. The drifting of the magnetic poles, their inexplicable reversal of magnetic polarity, the Van Allen belts of radiation, volcanic and earthquake activity, arctic areas with tropical fossils… the list goes on and on.
Perhaps the biggest mystery is the magnetic pole. “Like a magnet, the Earth has two magnetic poles. From time to time, the magnetic poles reverse polarity. …No one knows why this happens.”2
1 Dixon, Dougal, Geography Facts, (Marboro Books Corp, 1992).
2 Hall, Cally & O’Hara, Scarlett, Earth Facts (Dorling Kindersley Publishing, Inc., 1995).