Inner Core Facts

Inner Core Facts
Earth's innermost section is called its inner core, and is believed to be just as hot as the sun's surface. It was once believed that the earth's inner core was liquid, but Inge Lehmann - a seismologist - proved in theory in 1936 that the inner core was solid, and the outer core was liquid. The inner core is believed to be made up of an iron-nickel (metal) alloy. The earth, from the center moving outward, is made up of the inner core, the outer core, the lower mantle, the upper mantle, and the crust. Scientists continue to study the inner core, mostly through the use of seismic activity, as they try to learn more about it.
Interesting Inner Core Facts:
The temperature of the inner core is believed to be approximately 5400 degrees Celsius, or 5700 Kelvin. This heat is caused by three elements: residual heat from the formation of the earth, gravitational forces from the moon and the sun, and and radioactive decay of earth's inner elements.
The nickel alloy that makes up the earth's inner core is referred to as NiFe. Ni represents nickel, and Fe represents iron.
Scientists believe that the earth's inner core is growing slowly. It is also not believed to be uniform, as the seismic waves passing through do so at different speeds.
Some believe that the earth's inner core formed between 2 and 4 billion years ago. This theory also states that it was entirely molten originally, and was not present when the earth originally formed 4.5 billion years ago.
The earth's inner core is approximately 1500 miles wide. It is estimated to be approximately 1,802 miles below the earth's surface (crust).
Some scientists believe that the earth's inner core spins at a faster speed than the rest of it - at a rate of 2/3rds of a second faster.
Earth's magnetic field is not created by its solid iron and nickel inner core. Instead it is created by the earth's outer core, made of molten iron and nickel. The magnetic field is created when the outer core flows around the inner core.
Some find it hard to believe that the inner core can be solid, considering how hot it is. This inner core is able to remain solid because the center of the earth exists in extremely high pressures.
Although the inner core is made up primarily of nickel and iron, it also includes elements that are capable of dissolving in iron such as cobalt, gold, and platinum. These elements are called siderophiles.
Some scientists believe that the earth's inner core actually has another inner-inner core. They believe it formed approximately 500 million years ago due to a geological change.
In addition to seismic activity, scientists use a variety of other information to learn about the earth's inner core. These additional methods involve lab experiments, meteorite analysis, computer modeling, and reading of data.
The inner core makes up approximately 1.7% of earth's total mass, while the outer core makes up approximately 30.8% of the earth's total mass.

Related Links:
Geology Facts
Animals Facts

Educational Videos