The core of Earth is made out of iron and nickel. The outer core's temperature is so hot that it melts the metal. The inner core is solid metal. What causes these differences?

Question

The core of Earth is made out of iron and nickel. The outer core's temperature is so hot that it melts the metal. The inner core is solid metal. What causes these differences?
OPTIONS

The outer core is 2,300 km thick.

The inner core is kept solid by the intense pressure of all of the layers above it.

The inner core has a cooler temperature, allowing the metal to remain solid.

The inner core is made of a different metal.

GPT-4o mini · Answer

The correct option is: **The inner core is kept solid by the intense pressure of all of the layers above it.** The intense pressure at the center of the Earth causes the inner core, despite its high temperature, to remain in a solid state, while the outer core is liquid due to lower pressure allowing the metal to melt.