Journey to the Centre of the Earth

Kate Roach

November 2004

In Channel 4's Journey to the Centre of the Earth, British explorer Monty Halls follows in the footsteps of his hero Jules Verne, who wrote the classic of the same name. Halls is a genuine fan, and like Verne, he gets help from the brightest minds and the latest scientific innovations to plan the 4000-mile trip to Earth's core. Whereas Verne's explorers enter a dormant volcano to find giant mushrooms, dinosaurs and living fossils inside Earth, Halls finds an altogether less hospitable environment. Beyond the caves and the mines into which he descends lies bubbling magma, boiling rock and compressed molten iron.

The journey to the centre of Earth is an 8000-mile (12,875km) round trip into the unknown. We know less about the ground under our feet than we know about the skies above our heads. At present, a few adventurous tourists are kitting themselves out for the journey of a lifetime into space – they, at least, have some idea about what they will meet. Professional astronauts regularly travel hundreds of thousands of miles into space and yet the measly 4000 miles (6467km) under our feet remains uncharted territory. If it's your fancy to be the first to plunge to the depths, then read on …

No-one has ever been as far as you intend to go so you'll need the best tourist guides that money can buy. The people you need are not your average type of holiday guides. And if they don't seem to put your comfort first, give them the benefit of the doubt because they do know more than anyone else does about your destination. They are Earth scientists, geologists, seismologists, vulcanologists, petrologists and microbiologists. Listen hard to what they have to say before you leave because you're going to be exposed to temperatures and pressures that are unimaginably, horrifyingly large. Pressures at Earth's core are four million times greater than they are on the surface and the temperature is a whopping 7000°C.

Your Earth craft must tunnel as it goes, and in order to survive the crushing pressures it must be reinforced with diamond. As you descend, the temperature will rocket sky high by 30°C or so for every mile you go down. You must have a seriously advanced cooling system to cope with this. Pipes made from the latest technological advances in carbon nanotubes might be strong enough to withstand the battering. These will continually deliver coolant down to your craft at its deepest reaches and return the liquid to the surface, bringing with it the searing heat that threatens to fry you in your seat.

If this hasn't put you off and you're still up for the trip, before you step into your craft and prepare for your journey to the centre of Earth, take some time out to follow the guides below.

Earths crust

The outermost layer of Earth is called the crust. You might imagine something that's thin and crispy, but no, you have 22 miles (35km) of hard drilling to do to get through this crust. And however many days, weeks or months this might take you, bear in mind that the crust makes up only 0.1% of Earth's total volume – this will be one long journey!

First, where to start? The world's deepest cave system only extends about a mile downwards. The Taratoga gold mines of South Africa could take you close to the 2-mile mark, but your best bet is to start tunnelling from the Mariana Trench. This is the deepest ocean trench, plunging 7 miles (11km) down under the Pacific Ocean. You won't be the first to visit – in 1960, Swiss ocean engineer Jacques Picard and US Navy Lieutenant Donald Walsh took the deep-sea submersible Trieste into the trench. They lived to tell the tale. Will you? Take a look at the links below and learn as much as you can before you leave.

Earth's mantle

The mantle runs from 22 miles (35km) at its boundary with the crust down to about 1802 miles (2900km), where it meets the core. Now you'll have to battle through a 1780-mile (2865km) stretch of searing hot molten rock. On this leg of the journey you will have to be careful not to be swept up by the enormous tide-like forces of moving liquid rock. These vast convective systems are so powerful they can literally move mountains – you'll be face-to-face with the agent of continental drift. You must also plot a careful course through the numerous hot plumes of rising superheated magma that are being thrust up through Earth's crust miles above you. This is the hot lava that regularly comes spewing out of the mouths of active volcanoes and massive mid-ocean ridges. Not a pleasant journey. Check out the links below and chart your course carefully.

Earth's core

If you've survived the mantle seas, prepare for an even rougher ride. You will meet the outer liquid core at about 1802 miles (2900km). This is molten iron. Providing your craft holds up, not least your cooling system, you'll be able to study the source of Earth's magnetic field at first-hand. Humans have made use of it ever since the invention of the magnetic compass in the 12th century. Zoologists think that many animal migrations are also guided by the silent push and pull of magnetic north. The spectacular Northern Lights, the Aurora Borealis, are a product of charged particles from the sun interacting with Earth's magnetic field. Whilst scientists believe that the magnetism arises from convection currents in the liquid iron outer core, no-one really knows for certain. This is your chance to find out!

Finally, at about 3170 miles (5102km), you will meet the inner core. Solid, compressed, hot, crystallised iron. I hope you make it back safely.

Discover more about what you might expect to see by reading the links below.

Find out more

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Books

	Journey to the Centre of the Earth by Jules Verne (Oxford University Press, 2004) Classic 19th century French novel consistently praised for its style and its vision of the world. Professor Lidenbrock and his nephew Axel travel across Iceland, and then down through an extinct crater toward a sunless sea where they enter a living past and are confronted with the origins of man. Get this book
	20,000 Leagues Under the Sea by Jules Verne (Signet Classics, 2001) Verne's classic tale of Captain Nemo and the submarine Nautilus has hugely influenced 20th century popular culture. Its themes are universal, its style humorous and grandiose and its construction masterly. Get this book
	Earth by Douglas Palmer (Dorling Kindersley, 2003) Provides a perspective on our planet's apparently infinite range of natural features and the system of interlinking forces that formed and continue to change them. Get this book
	The Earth: An intimate history by Richard Fortey (HarperCollins, March 2004) Tells the geological story of planet Earth for the general reader with a guided tour around a number of geological sites with which the author is personally familiar, such as the Grand Canyon, the European Alps and Mount Vesuvius. Get this book
	Earth Story: The shaping of our world by Simon Lamb and David Sington (BBC Books, 2003) Unravels the fascinating history of Earth from its formation to the dawn of human civilisation. Get this book
	Essentials of Geology: Portrait of Earth by Stephen Marshak (W W Norton, 2003) An introduction to geology that weaves the theory of plate tectonics and the concept of Earth systems science into its narrative from the beginning. This book strives to create a modern, coherent image of our planet. Get this book