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Why is the Earth made up of so much silicon?

by mildpiranha
Tags: earth, silicon
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mildpiranha
#1
Dec21-08, 10:12 AM
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Why is the Earth made up of so much silicon?
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Integral
#2
Dec21-08, 11:52 PM
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The chemical composition of the earth is determined by the composition of the debris cloud from which the solar system formed. These debris are "cinders" of stellar furnaces and perhaps a super nova or 2. Iron is the true cinders of stellar fires as there is no release of energy on either fusion or fission of an iron nuclei.
mildpiranha
#3
Dec23-08, 04:09 AM
P: 6
But why is the Earth made of such a high proportion of silicon? Would all other rock planets have a similiar composition of silicon?

chemisttree
#4
Dec23-08, 07:35 PM
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Why is the Earth made up of so much silicon?

Are you talking about the abundance of silicon in Earth's crust? I believe it is roughly 16% by weight in the crust and about 9-10% in the whole earth. Iron is about 1.5% in the crust and about 46% in the whole earth. Earth is mostly iron. Lighter elements like the various oxides of silicon tend to float on top and have hardened into crust.
mildpiranha
#5
Dec24-08, 04:53 AM
P: 6
I am talking about the composition of the Earth, not taking into account atmospheric composition. From wikipedia....The mass of the Earth is approximately 5.981024 kg. It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulphur (2.9%), nickel (1.8%), calcium (1.5%), and aluminium (1.4%); with the remaining 1.2% consisting of trace amounts of other elements.....

looking at the table below which I found, I am curious as to why there is so much silicon on Earth?

most common elements in the universe

Element (Parts per million mg per kg)
1 Hydrogen 750,000
2 Helium 230,000
3 Oxygen 10,000
4 Carbon 5,000
5 Neon 1,300
6 Iron 1,100
7 Nitrogen 1,000
8 Silicon 700
9 Magnesium 600
10 Sulphur 500

SOURCE: The Top 10 of Everything 2006 by Russell Ash, page 10


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