The complete crossing of our planet is a fantasy that has nourished the imagination since Jules Verne’s novel, Journey to the center of the Earthpublished in 1864. In this fiction, Professor Lidenbrock, an eccentric scientist specializing in volcanoes and his nephew Axel, undertake this fabulous journey through the bowels of the Earth.
However, this dream today comes up against insurmountable physical and technological obstacleseven if some projects went very far, even too far in some cases.
The titanic challenges of underground exploration
To understand why such an endeavor is impossible, we must first understand the internal structure of our planet. This is organized into three main layers. The earth’s crust, a thin film comparable to the skin of an apple, constitutes the most superficial part of which the tectonic plates are a part. Beneath it lies the mantle, several thousand kilometers thick, composed of heavy rocks in perpetual movement. In the center, the metal core reaches dizzying temperatures, between 2,500 and 5,200° C.
The most ambitious project for exploring the earth’s depths undoubtedly remains the drilling of Kola, in Russia, which lasted from 1970 to 1989. This technical feat of the USSR made it possible to reach 12.2 km depth before the teams had to stop: excessive temperatures damaging the equipment, technical failures and astronomical costs. Impressive, but the Earth’s core is more than 2,900 km deep.
Going further would simply be impossible. Indeed, at such depths, the pressure exerted by the upper layers on the walls of the boreholes increases inexorably with depth, as a diver feels in his ears while descending underwater. The deeper we dig, the more the heat also increases. Although exact data is not always published in detail, it is estimated that the temperature at the bottom of the Kola borehole reached more than 180°C.
Another case also perfectly illustrates this impossibility: that of the Bingham Canyon open pit mine in Utah. Despite walls carefully calculated to be three times as wide as they are deep, a landslide in 2013 caused the collapse of 145 million tonnes of rock. However, this copper mine is only 1.2 km deep and 4 km wide.
Drilling would theoretically have the advantage of moving less material than traditional excavation. However, even with current technologies capable of drilling a few centimeters per minute into the hardest rocks, the theoretical complete crossing of the Earth would require several centuries. Not to mention that the weight of the drill rods would quickly become unmanageable and the movements of the Earth’s mantle would end by deforming and collapsing any dug well.
Extreme temperatures, colossal pressure and the presence of magma, gas and liquid metals at depth thus make it definitively impossible to realize the Vernian dream. This trip is therefore to be brought back ad vitam aeternam in the science fiction category; If there is one thing that we cannot change, it is the laws of physics, which will forever constitute an inviolable framework which governs our Universe.
- Digging through the Earth is impossible due to the overwhelming pressure, extreme temperatures, and unstable materials at depth.
- The most ambitious drilling projects, such as Kola, have only reached 12 km.
- The laws of physics make this fantasy unrealizable, despite scientific and technical advances.
