The place where 99% of the Earth's gold is concentrated.

Most of the Earth's gold is concentrated in the Earth's core, beyond human extraction capabilities.

The amount of gold mined by humans is only a small fraction of the gold found in the Earth's core. Photo: Phawatt — The amount of gold mined by humans is only a small fraction of the gold found in the Earth's core. Photo: *Phawatt*

Experts estimate there is so much gold on Earth that it could cover every inch of land to a depth of 50 cm. But gold remains a rare and precious metal because most of it sinks to the Earth's core and is beyond the reach of any miners, according to IFL Science .

The Earth's core is composed primarily of iron and nickel. Researchers discovered this through how seismic waves travel through the core from earthquakes. However, the presence of impurities alters the wave density, but it's difficult to pinpoint them precisely unless their radiation contributes to the high temperatures, similar to uranium and thorium.

The existence of asteroids containing rare precious metals remains a mystery. However, in 2006, a group of scientists found a way to estimate their number. According to them, some asteroids have a similar composition to Earth because they formed in the same region on the protoplanetary disk. By measuring the composition of carbon-chondrite meteorites from these asteroids, they were able to calculate the amount of each element present on Earth. Subtracting the known density in the crust and mantle, the research team could deduce the amount of that element in Earth's core.

Professor Bernard Wood, a geologist at Macquarie University, and his colleagues examined the early history of Earth's development, beginning with the formation of the solar system more than 4.5 billion years ago and focusing on the origin of Earth's molten metallic core. According to them, Earth may have been covered by oceans of molten rock hundreds of kilometers deep during this period. This ocean of magma reacted with metals throughout the planet's development, extracting many important elements, including gold, and depositing them in Earth's iron-rich core.

After comparing Earth's crust to meteorites, the research team found that Earth is very similar to meteorites chemically, but its crust has lost most of the elements that are insoluble in iron, such as gold, platinum, and nickel. The only place for them to accumulate is in the molten core.

Based on this, Wood and his colleagues were able to calculate the amount of each element mixed with liquid iron and discovered that over 99% of Earth's gold is located in the core. Similarly, extant asteroids, especially those representing the core of a microplanet, still contain large amounts of elements. Accessing them is quite difficult, but still much easier than drilling to the core. That's why NASA plans to launch a probe to asteroid Psyche in two months.

Papers about the Psyche mission often estimate the asteroid's value at around $10 quadrillion, but if such a large source of rare metals were available, its value would plummet. The same is true for gold. If humans could extract all the gold from the core and bring it to the surface, nobody would buy it anymore.

An Khang (According to IFL Science )

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