What is our earth made of?

From the crust to the core, each layer plays a crucial role in shaping the planet as we know it. California Academy of Sciences reveals more details about our earth.

At the outermost layer is the crust, where all life exists. Although it ranges only 5 to 70 kilometres (3 to 43.5 miles) in thickness, this “skin” of the Earth supports diverse ecosystems, mountainous landscapes, and vast oceans. Made primarily of silicate minerals like granite and basalt, temperatures in the crust start at 0°C on the surface, reaching up to 1,000°C at its deepest points.

Beneath the crust lies the mantle, a vast, semi-solid layer stretching deep about 2,900 kilometres (1,800 miles). This layer, composed of silicates rich in magnesium and iron, acts as a tectonic powerhouse; its slow-moving, viscous material drives the tectonic activity that creates earthquakes, volcanoes, and mountain formation.

The mantle’s temperature, from 1,700°C in the upper region to around 3,500°C at its core boundary, helps maintain the convective flow responsible for these powerful geological processes.

Below the mantle lies the liquid outer core, a swirling layer of molten iron and nickel approximately 2,200 kilometres (1,400 miles) thick. Its dynamic movement generates Earth’s magnetic field, a crucial shield protecting us from harmful solar radiation.

Temperatures in this layer range from 3,800°C to 5,000°C, making it one of Earth’s hottest regions. At the planet's centre lies the inner core, a dense solid iron and nickel sphere.

Despite temperatures reaching 5,000°C and 6,000°C, immense pressure keeps this layer solid. Spanning 1,230 to 1,530 kilometres (760 to 950 miles) in thickness, the inner core remains one of Earth’s most mysterious regions.

California Academy of Sciences also highlighted even more about Earth’s depths, suggesting that parts of the mantle may contain remnants of a protoplanet named Theia, which collided with Earth around 4.5 billion years ago.

Dense regions below West Africa and the Pacific Ocean could hold the key to understanding more about Earth’s ancient past, offering clues about its formation and early development.

Scientists have also discovered vast amounts of water bound within minerals in the mantle, hinting at an entirely hidden water cycle operating deep within Earth.

This revelation could transform our understanding of the hydrological cycle, as well as Earth’s ability to store and release water over geological timeframes.

Together, these layers and the newly uncovered mysteries within them illustrate the incredible complexity of our planet’s structure. Each component, from the crust to the core, tells a story of Earth’s past while hinting at secrets still waiting to be uncovered.