what is the thickness of the inner core in kilometers
The Earth's inner core is the Earth's innermost part. It is primarily a solid ball with a radius of about 1,220 kilometres, which is about 70% of the Moon's radius. It is composed of an ironânickel alloy and some light elements. The temperature at the inner core's surface is approximately 5,700 K, which is about the temperature at the surface of the Sun.