Composition of the Earth's core

In summary, most scientists believe that the Earth's core is primarily composed of iron and nickel, with smaller amounts of sulfur and oxygen. This is because during the Earth's molten state, heavier elements sank and compacted while lighter elements rose on convection currents. The lack of heavier elements, such as uranium, in the core can be attributed to their lower cosmic abundance and tendency to bind with less dense minerals. The heat of the Earth's core is primarily generated by the latent heat of crystallization and radiogenic decay of elements, mainly occurring in the mantle rather than the core itself.
  • #1
crazylum
8
0
I understand that most scientists believe that the Earth's core is composed of iron, nickel and perhaps some other elements such as sulfur and oxygen. I also understand that they believe that the Earth's core formed during a time when the Earth was molten and that the core was formed by heavier elements sinking and compacting and lighter elements rising on convection currents. My question is if it was formed by this process why is it not composed of elements heavier than iron such as uranium?
 
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  • #2
First you might consider the cosmic abundance of uranium in relation to iron. I think you'll find there's a hell of a lot more iron in the universe than there is uranium!

Second, uranium tends to get obund up in not especially dense minerals, like zircons, which makes it hard to sink.
 
  • #3
Now this is interesting; I had always assumed ther were non-negligable amounts of heavy elements in the core. I heard a long time ago that the original heat of compression from Earth's formation should have been radiated away eons ago, and one speculation for why the core is taking so long to cool is decay of radioactive elements. From there, I guess I just assumed that these heavier elements must be more abundant in the core, having sunk there during planetary formation.
 
  • #4
I don't know where you heard that, but it's wrong. Some of the heat generated in the Earth is radiogenic, although the decay of U, Th, and K is mainly occurring in the mantle. Note that the outer core is liquid, a lot of heat is released as latent heat of crystallization, as the outer core gradually freezes to develop the ever expanding inner core.
 

What is the composition of the Earth's core?

The Earth's core is primarily composed of iron and nickel, with smaller amounts of other elements such as sulfur, oxygen, and silicon.

How do scientists know the composition of the Earth's core?

Scientists use seismic waves, which are generated by earthquakes, to study the Earth's interior. By analyzing the speed and direction of these waves, scientists are able to determine the composition of the Earth's core.

What is the temperature of the Earth's core?

The temperature of the Earth's core is estimated to be around 5,400 degrees Celsius. This high temperature is due to the immense pressure and heat generated by the Earth's gravity and radioactive decay of elements.

Is the composition of the Earth's core the same as the rest of the planet?

No, the composition of the Earth's core is different from the rest of the planet. The outer layers of the Earth, such as the crust and mantle, are composed of different elements and have different densities compared to the core.

How does the composition of the Earth's core affect the planet?

The composition of the Earth's core plays a crucial role in the planet's magnetic field and the movement of tectonic plates. It also influences the formation and evolution of the Earth's surface, including the continents and oceans.

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