Figure of the month: 45 centimeters

An earlier "figure of the month" article dealt with the vast gold deposits on the asteroid Eros, which is unattainable for mining companies, at least for the foreseeable future. According to a theory by geologist Dr Bernard Wood of Macquarie University in Australia, there might be enough gold inside Earth to coat the entire surface of the blue planet in a 45 cm layer.

Wood's theory is based on numerous experiments and insights into the formation of our planet. Over 30 to 40 million years, Earth was formed due to continuous collisions of asteroids. Therefore, its chemical composition must correspond to that of asteroids, which contain, in relation to their respective mass, much more gold than can be found on Earth. On its surface, on the other hand, minerals such as silicone or calcium are found in exactly the same relative quantity as on the asteroids that formed the blue planet. So where has all the asteroids' gold gone? Wood is convinced that dense, "iron-loving" materials such as nickel, platinum and gold melted during the formation process of Earth and were pulled in the direction of its solid iron core. Since then, these elements have been floating in the liquid magma stream of Earth's outer core.

So close – yet so far away

The liquid gold around the earth's core is located almost 3000 km under the surface – and is thus unfortunately just as inaccessible as the gold in space. So far, the deepest drillings into Earth have not advanced much further than 12 km. 

By the way: the gold deposits mined on Earth to date stem from smaller asteroids that collided with the planet after its solid and liquid core had already been formed.