What started with Jules Verne’s postulation of Earth’s Core, in the name of Science Fiction, has now delved into something much deeper. Literally.
How Did We Come Up with The Present Idea of Earth’s Core?
In 1864, Jules Verne published Journey To The Center of the Earth, which was, and still is one of the most critically acclaimed science fiction still in publication. The book deals with a Professor and his nephew’s journey into a large system of volcanic conduits, accessible from the crater of the Icelandic volcano Snæfellsjökull. The story then revolves around how they descended through the descended through the sedimentary layers of the crust into its foundation. About 87 miles beneath the surface they discovered an underground sea occupying a cavern, roughly the size of Europe, hollowed in the granite of the lower crust.
This book was the result of the amalgamation of research, creativity and imagination. It is claimed that the book may have been base on the works of of geologists like Alcide d’Orbigny, who classified rock strata by their fossil content, Charles Sainte-Claire Deville, who studied volcanoes and Elie de Beaumont, who worked on the origin of mountain ranges.
What started as a fascination to understand geology and seismology has evolved into a much bigger idea now!
In Verne’s book, the characters used the empty volcanic conduit as an entrance into Earth’s interior. It was a very popular belief at that point in time, that once a volcano erupts and is devoid of the lava, it could connect a volcanic crater to magma chambers which would be buried deep into the ground. However, this notion was dismissed in the modern times as research proved that such conduits are way too small to allow for human movement, as they even have a lot of solid rocks acting as obstructions.
Even though Verne’s book has elements which seem so real that it gets difficult to differentiate between fact and fiction, not all of it seems false after all. He may have been right when he talked about finding a chamber full of crystals underground. It’s a known fact that crystals grow in the right condition and require a lot of time. So it could be possibly true, as it’s very rare that perfect conditions to grow a crystal are usually met. Yet, the only place which does provides for such perfect conditions is in the Cueva de los Cristales, located in the Naica Mine, Chihuahua (Mexico).
Not just this, but in 1828, when the mine of Naica was opened to mine for silver, lead and zinc ore, almost a century later in 1910, a natural cave was discovered. Named Cueva de las Espadas, there were almost three-foot long blade-like gypsum crystals covering the walls of the cave. Cueve de las Espadas does mirror most of Verne’s description. Which leads to the assumption that it is probably possible to find the largest crystal at the core of Earth’s centre.
Earth’s solid inner core could have a hidden inner layer that we do not have the knowledge of. Research has shown that the core, which is a ball of superhot iron and nickel alloy, displays a crystalline structure. Yet, the exact nature of this aspect is still as mystery. There are approximations and expectations of what it could be like, for example, it would be largely relating to do with changes in the structure of iron under extreme temperatures and pressure.
The Earthquake Mapping
Even though the first hint that there is a possibility of finding something interesting at the inner core lurked in around 1980s, there was no way of conducting research or gaining material evidence on what exactly it is about, as the temperature inside, soars up to that of the sun’s! Yet, scientists use earthquake waves to draw images of the core. During an earthquake, waves appearing on one side of earth, are detected on the other side, carrying slight changes, which the scientists pick up on and use to recreate of images of what they’ve passed through.
Strangely, when waves pass through the core from north to south, they travel faster than waves passing through the core parallel to the Earth’s equator. No one knows why this is. Mostly, this just represents how even though we’ve set out on a conquest to conquer the moon, and discover different planets; we’re probably unsure of our own!