So What Is At The Core Of The Earth?

By James Donahue

When you think about it, scientists appear to know more about Mars and the Moon than they know about the depths of our own planet.

We have drilled a few miles into the crust of our planet, and there has been a recent attempt to drill into what is believed to be a hot semi-molten substance that is shifting and constantly in motion, affecting the movement of plate tectonics and volcanism.

The crust, that part of the planet where we live, farm and mine for minerals, is estimated to be about 22 miles thick. That means everything below this is an unknown. Thus scientists have only guessed at the rest of the core from information gleaned from seismographs and a few other clues found from ancient catastrophic events.

Information from the seismograph reports have long supported a theory that a solid ball of something, perhaps iron, exists at the core of the Earth. As seismograph instruments and the methods of reading and studying the signals during major quakes improves, the information tends to support the existence of a heavy core estimated to be about the size of the Moon.

No one can say what exists within this core. Some scientists guess that it is comprised of the planet's heaviest metals, all so hot they are in a thick molten state, but compressed. Also new seismographic data indicates that this giant orb in the planet's center is spinning, and turning at a speed faster than the planet. That information astounds the science community. It is believed that the spinning ball within the planet has much to do with the magnetic energy that exists throughout and around the Earth.

So where did all of the heat originate in the heart of our planet? While some of it could be caused by thermonuclear action, there is a theory, based on a study of the history of the changing crust of the planet and the constant movement of the tectonic plates, that the planet still holds much of the heat generated at the time it was created. The theory suggests that the Earth has been slowly cooling down, which is causing the constant changes occurring on the planet's surface.

For example, about a billion years ago all of the continents were thought to have been part of a single super land mass referred to as Pangea. Because the plates were very hot they were thin and when they bumped into each other, they did not collide with force like they do today, but just adhered. Thus there were no mountains.

As the planet has cooled, however, the theory suggests that the tectonic plates became thicker and heavier, with more and more of the hot molten material sticking to them. After a while they were heavy enough to collide with destructive force, creating shifts in the surface of the Earth and eventually forming mountains and various other interesting rock formations.

The planet is continuing to cool, and consequently, the earthquakes caused by the collisions of the moving plates are getting more and more violent. This theory also suggests that the constant changes on the surface, and occasional opening of volcanic heat that warms the oceans, melts the ice caps and stops the natural flow of ocean currents northward, generates periodic ice ages.

It would have been a natural form of global warming that can give us all an idea of what to expect as our planet heats this time around.

As for a peek at the mantle, contemporary efforts to drill through the crust and reach the mantle have been going on now for more than a decade, but apparently without success. Sinking a drill bit 22 miles into the rock is a major and costly undertaking.

But something happened about 1.8 billion years ago that has already given us a clue at what is down there. It seems the Earth was struck by a space rock the size of a large mountain that blasted a 125-mile-wide crater at Sudbury, Ontario. It went so deep that it opened a massive chasm into the mantle, and the molten material in it exploded outward, turning a part of our planet inside out.

Most of that crater has collapsed in on itself since that catastrophic event, but the blast left a deposit of materials from the mantle that gives us some clue as to what can be found there.

In one publication, University of Toronto geologist James Mungall, who led a study of the area, said the team found high concentrations of iron, nickel and platinum as well as an enrichment of indium, a material commonly associated with extraterrestrial rocks. Its presence is a strong indicator of an impact, Mungall said.