Earth's inner core

Earth's inner core is the innermost geologic layer of the planet Earth. It is primarily a solid ball with a radius of about 1,220 km (760 mi), which is about 20% of Earth’s radius or 70% of the Moon's radius.^[1]^[2]

There are no samples of Earth's core accessible for direct measurement, as there are for Earth's mantle.^[3] Information about Earth's core mostly comes from analysis of seismic waves and Earth's magnetic field.^[4] The inner core is believed to be composed of an iron–nickel alloy with some other elements. The temperature at the inner core's surface is estimated to be approximately 5,700 K (5,430 °C; 9,800 °F), which is about the temperature at the surface of the Sun.^[5]

^ Cite error: The named reference monner2010 was invoked but never defined (see the help page).
^ Cite error: The named reference eng1974 was invoked but never defined (see the help page).
^ "Earth's Interior". National Geographic. 18 January 2017. Archived from the original on 11 April 2021. Retrieved 17 November 2021.
^ Cite error: The named reference alle1995 was invoked but never defined (see the help page).
^ Cite error: The named reference alf2007 was invoked but never defined (see the help page).

[monner2010-1] Cite error: The named reference monner2010 was invoked but never defined (see the help page).

[eng1974-2] Cite error: The named reference eng1974 was invoked but never defined (see the help page).

[3] "Earth's Interior". National Geographic. 18 January 2017. Archived from the original on 11 April 2021. Retrieved 17 November 2021.

[alle1995-4] Cite error: The named reference alle1995 was invoked but never defined (see the help page).

[alf2007-5] Cite error: The named reference alf2007 was invoked but never defined (see the help page).

[1]

[2]

[3]

[4]

[5]