The Earth's inner core is a "planet within a planet".

A new study of the Earth's inner core has uncovered a complex "planet-within-a-planet" structure of the Earth.

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New discoveries suggest that the Earth's inner core resembles that of a small planet. (Source: Indiatimes)

A team of scientists from the University of Utah (USA) is trying to understand the Earth's inner core. Essentially, it's a solid metallic sphere located inside our planet.

Research suggests that, contrary to previous assumptions that the Earth's inner core is homogeneous, it is more likely to resemble a carpet with many different "fabrics."

"For the first time, we confirm that these heterogeneous materials are everywhere inside the Earth's core," said lead author of the study, Guaning Pang, in a press release from the University of Utah.

Researchers analyzed seismic data from a global network of detectors set up to record nuclear explosions. Seismic waves generated by earthquakes provide valuable information about the Earth's inner core as they travel through the Earth's crust, the mantle (the most viscous layer beneath the crust), and the planet's core.

"Earth was formed from ancient asteroids in space. They collided and released a lot of energy. So, the entire planet, while it was forming, was like a molten sphere," said Keith Koper, a seismologist involved in the study.

“Metallic elements (like iron) are heavier and they formed the planet’s core. The metals sank inward, while the layers of liquid rock remained on the outside, and then they cooled and solidified over time. The reason all the metals are at the bottom is because they are heavier than the rock,” he said.

The Earth has a diameter of approximately 12,750 km. The internal structure of the blue planet consists of four layers: an outer rocky crust, followed by a rocky mantle, then an outer core made of magma, and a solid inner core.

Both the outer shell of the inner core and the innermost sphere (core) are hot enough to melt. However, they are a solid iron-nickel alloy, due to the incredible pressure at the Earth's core which keeps the inner core in a solid state.

“The Earth’s core is like a small planet inside the Earth. Indeed, it’s a solid ball, roughly the size of Pluto and slightly smaller than the Moon,” said geophysicist Hrvoje Tkalčić of the Australian National University.

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