what is the approximate diameter of earth's core
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 (760 miles), which is about 70% of the Moon's radius. It is composed of an iron -- nickel alloy and some other elements. The temperature at the inner core's surface is approximately 5,700 K (5,430 ° C), which is about the temperature at the surface of the Sun.