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History of Earth - The Iron Catastrophe

Updated on August 2, 2010

History of Earth - The Iron Catastrophe

Twenty-five million years after it's formation, Earth began to melt. One of the reasons was the residual energy from all the collisions the planet was still experiencing. Another reason was the radioactive decay still going on after the supernova. But the most important factor was the gravitational pull caused by all the matter being in one place, which caused the planet to contract. This contraction raised the pressure and temperature of Earth's core over time.

The onset of gravity also created on earth the phenomenon known as weight. The scientific definition of weight states that weight is the force that gravity exerts on an object. Without gravity no force would be exerted on an object, and therefore it would have no weight. That is why objects in space are said to be weightless. An object can have mass but no weight. This is also why an object can only be said to be 'heavy' where gravity exists.

Because the earth was molten in its early stages, the elements it consisted of could move around freely. And because of the strong gravitational pull, the lighter elements like carbon and magnesium floated to the surface, while the heavier elements like iron and nickel sank to the bottom. The movement of iron turned out to be very important for the future of Earth as it is the most common element on Earth and makes up about one third of it's total mass. The drops of iron proceeded to Earth's core, slow at first, but eventually it caused a catastrophe.

The word 'catastrophe' usually refers to the 'culminating act in a drama'. Because it was usually applied to tragedies, it became associated with the disasters that happened to tragic heroes. The Iron catastrophe carried no such meaning though. It was a catastrophe in the original sense of the word. It lasted between one hundred million and five hundred million years and was the culminating act in the earth's drama, because it created the layers that forms Earth's current structure, which is a solid iron-nickel inner core(solid because of the most pressure that far down), a molten iron-nickel outer core(molten because the pressure outside the inner core is not quite so large), a dense rocky mantle, and a less dense rocky crust.

Earth's Layers

Source: The Bedside Baccalaureate


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    • profile image

      Edward 7 years ago

      Factually correct in most areas however I would suggest the detail is fairly lacking.

    • kellydove profile image

      kellydove 7 years ago

      very nice information

    • thevoice profile image

      thevoice 7 years ago from carthage ill

      first rate hub work thanks