The inner core is hot enough to be liquid, but due to the pressure, it is solid. Even though it is hotter than the surface of the Sun, the crystallized iron core of the Earth remains solid.

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 solid because it is made of very dense, or heavy, materials - like iron and nickel. The immense pressure from the other parts of the planet keep the extremely hot iron of the Earth's inner core from melting. Given enough presssure, in spite of high temperatures driving atoms apart, the atoms can be squeezed closer together increasing the density to alter the expected state of matter at those high temperatures. Seismologist Inge Lehmann was the first to discover the inner core as being solid and covered by a liquid outer core. This is because of the relative melting points of the different layers (nickel–iron core, silicate crust and mantle) and the increase in temperature and pressure as depth increases. The outer core is where the circulating conducting liquid generates the … It has an estimated radius of 1220 km (768 mi). But it is solid as the other variable, pressure at the inner core is very high due to the immense gravity. Answer 3: It turns out that many materials can be a solid at a higher temperature if the pressure is also higher. Is the inner core of the earth made out of hot liquid? The inner coreis the innermost layer of the Earth, and is believed to be a solid ball composed of iron and nickel along with some light elements (e.g., oxygen, sulfur, silicon). Earth's innermost section is called its inner core, and is believed to be just as hot as the sun's surface. Even though it is very hot, these materials don't "melt" very easily, so they stay solid. Why is the inner core of the earth solid if it is the hottest layer? The inner core is solid, the outer core is liquid, and the mantle solid/plastic. The core of the Earth is made up mainly of iron, in an outer liquid layer and an inner solid layer.