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  • Deep in western Russia, the frigid desert contains the remnants of one of the most ambitious

  • scientific experiments ever performed. It's a ruin now, a wasteland of jagged metal and

  • crumbling concrete.

  • If you search around long enough, you will find a rusted disc, bolted to the earth. So

  • unassuming that you might even try to pick it up. But you won't be able to.

  • It's the welded-shut cap of a borehole that plummets more than twelve kilometers into

  • the earth, deeper than the deepest depths of the ocean. It's the deepest hole on earth.

  • It's called the Kola Superdeep Borehole, and its existence has nothing to do with petroleum

  • exploration. Rather, when drilling began in 1970, Soviet scientists hoped to eventually

  • drill down to fifteen thousand meters in order to gain a better understanding of the nature

  • of the Earth's crust. Because the truth is, we know less about what's under our feet than

  • what's on the other side of the solar system.

  • They drilled on and off for twenty-four years, and though they didn't quite reach their goal

  • when work came to a halt in 1994, the engineers had reached a record depth: 12,262 meters,

  • a record that still stands today.

  • Two decades later, the Kola Borehole remains a remarkable technological and scientific

  • acheivement. To drill it, engineers devised a new method by which only the drill bit at

  • the end of the shaft was rotated, the lubricant, in this case, pressurized drilling mud, was

  • pumped down through a custom drill bit, allowing it to spin. Instruments had to be invented

  • to take measurements at the bottom of the hole.

  • What did we learn by drilling a third of the way through the Baltic continental crust?

  • For one, there's water down there, at depths scientists didn't believe water could be found.

  • They suspect that the water formed from hydrogen and oxygen that were squeezed out of rock

  • crystals due to crazy high levels of pressure that far down.

  • Unlike groundwater, this water originated from the rock minerals themselves. Never before

  • had this been observed. Also surpising, how about microscopic fossils discovered by Russians

  • at depths of up to 6.7 kilometers?

  • Researchers catalogued twenty-four species of single-cell plankton microfossils over

  • the course of the project, and they weren't found in the kinds of deposits we're used

  • to finding them, like limestone and silica.

  • These were covered by organic carbon and nitrogen compounds, preserved thanks to those high

  • pressures and high temperatures so far below the surface. As for those temperatures, by

  • the time the engineers broke through the twelve kilometer mark, where rock samples were dated

  • at 2.7 billion years old, the heat became a major issue.

  • Researchers thought the temperature of the rocks would be about 100 degrees Celsius.

  • What they found were temperatures in excess of 180 degrees. It was this heat that caused

  • the drilling to come to a stop. Engineers described the rocks at 12 kilometers as acting

  • more like plastic than rock.

  • Of course, as astonishing as this project was, the Kola Superdeep Borehole only made

  • it through a tiny fraction of the Earth's layers. 12 kilometers is three times as deep

  • as humans have ever gone, but the eath's mantle desn't even begin until about 35 kilometers

  • below the surface.

  • The mantle then continues for another twenty-eight hundred kilometers; the center of the inner

  • core: more than sixty-three hundred kilometers below the surface.

  • Put another way, this borehole which took 24 years to drill, made it roughly 0.002 percent

  • of the way to the middle of the Earth. It's a big planet, you guys.

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  • fascinating depths of the cosmos.

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Deep in western Russia, the frigid desert contains the remnants of one of the most ambitious

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