Underland

I haven't said much thus far about the book I am reading aloud in the car. It is really fascinating, and unusual as well. It is Underland by Robert McFarlane. McFarlane has devoted much of his adult life to exploring what is underground. He has gone all over the world seeking out both natural and man-made subterranean rifts, caverns, tunnels, chambers, caves, catacombs - you name it, he's visited it. For example, in our reading, we are currently beneath the city of Paris. I guess we all know about the sewers from Victor Hugo's Les Miserables. But they are pretty tame stuff. Paris sits on a vast field of limestone. For over a century, that limestone was mined to build the city above the ground, creating hundreds of miles of tunnels and hundreds of small and large chambers on many levels, all below ground. The mining was unregulated until sinkholes developed which would suddenly swallow up whole neighborhoods: buildings, people, horses and all. They stopped mining, but left the spaces that had already been created. After a while, it was realized that all that space could solve a huge above-ground problem: too many dead bodies and too few cemeteries. Literally millions of remains were exhumed and stored underground, sometimes carefully, sometimes haphazardly, creating a vast labyrinth of catacombs. Eventually, that was sealed off to the public except a small bit for the tourist trade. (I remember seeing ads for tours of the catacombs when I was in Paris). Little did I know! Today it is illegal to go into the catacombs, but adventuresome urban explorers have no trouble finding ways in and keeping ahead of the police. McFarlane has joined them for some memorable explorations. It requires skill, daring, and a tolerance for claustrophobia. But there is a world to be explored under Paris, tunnels have names, chambers have names, maps have been made and are closely guarded, and there are surprises.

A scene in the Paris catacombs We have also learned about vast potash/salt mines in England that reach both under the mainland and far out under the sea. In one corner of those mines is a laboratory, the Boulby Undergroud Laboratory, where scientists are "trying to pinpoint material known as dark matter, which is believed to permeate the universe in the form of weakly interacting massive particles – or wimps. Incredibly, around 85% of the universe's mass is now thought to be made up of wimps. These particles permeate the space around us, flying through normal matter but only rarely interacting with it." Trillions of particles of dark matter are passing through our bodies constantly, and they are also penetrating deep into the earth. "At the location of the Boulby Underground Laboratory there is 1,100 metres of rock overhead. This makes it an ideal place for research because that 1,100 metres of rock results in a reduction in the rate of natural cosmic rays of a factor million compared to surface levels. With this, and with the surrounding rock salt being low in natural background radioactivity, Boulby makes an ideal site for ultra-low background and deep underground science projects." In simple terms, deep in the earth, the glow created by the collision of particles is more likely to be caused by dark matter than by other particles. Scientists are patiently waiting to see the afterglow of such a collision. McFarlane takes you on a tour of the mine and the lab and you get to meet some of the people there.

A schema of the Boulby Laboratory and a scene in the lab.