During the cold war, while the Space Race pitted the Soviet Union against the United States to conquer the skies, the two countries were also vying to drill as deep as possible into the earth.
The USSR embarked on drilling a hole in 1970 on the Kola Peninsula located east of Finland. By 1983 the project, named the Kola Superdeep Borehole, had reached a depth of 12,000 meters (39,000 ft). The project was then halted for a year to celebrate the milestone achievement. When drilling resumed, the drill went 66 further meters until a 5,000-meter section of drill string (interconnected lengths of pipe) twisted off and was left in the hole.
After the first hole was botched, drilling began again at 7,000 meters, in a new hole called SG-3. In 1989, 19 years after researchers had broken ground, the project reached 12,262 meters (40,230 ft = 7.6 mi). Although the original plan was for the hole to be drilled to 15,000 meters (49,000 ft), the project was unable to proceed due to the temperatures encountered. In recent years a few longer boreholes have been drilled, but the Kola Superdeep Borehole still holds the record for the deepest artificial point on earth.
The Soviet drilling project revealed just how little we know about our own planet. The temperature at this depth was predicted to be 100°C (212°F). Instead, they found temperatures reaching 180°C (356°F). The drilling project was ended due to the higher-than-expected temperatures. The material being drilled out of the hole reportedly had a plastic-like consistency, and came out of the hole “boiling” with hydrogen. If the project was to continue to its original goal of 15,000 meters, it would have encountered temperatures of approximately 300°C (570°F) where the equipment would be inoperable.
It had been assumed that the earth’s crust increased in density with depth. The hole instead revealed highly-fractured rock that was saturated with water. Until then it was assumed that water could not be found underneath the impermeable layers of rock. Researchers believe that the extreme temperatures and pressures at this depth caused atoms of oxygen and hydrogen to decouple from surrounding minerals and form into water. Apparently, it is possible to squeeze water from a stone.
Perhaps one of the most important findings from the project was the discovery of 24 species of microscopic single-cell plankton fossils. The plankton, normally encased in limestone or silica, were instead found in organic compounds. Even more surprising was how, despite the extreme temperatures and pressure, the fossils had remained intact for 2.7 billion years.
The project discontinued drilling operations in 1992 and was closed down in 2005 due to lack of funding. Equipment for drilling and research has since been scrapped and the site abandoned in 2008. The borehole itself remains, with a metal cap drilled and welded to seal off the hole.
The drilling endeavor had remained largely secret and managed to inspire urban legends in the U.S. about a “well to hell” located in an unidentified area in Siberia. In 1989 rumors had spread to U.S. airwaves that, after drilling to a depth of 14,400 m, the drill bit spun wildly as though it had reached a pocket of hollow space below. Researchers supposedly lowered a heat-sensitive microphone into the hole and heard what sounded like the muffled sounds of the damned, to which half of the crew fled the site. The legend even had a resurgence in the late 1990s after alleged audio from the well to hell surfaced.
The Kola Superdeep Borehole may not have reached hell itself, but it went further than any drill has to date. The data collected from the project is invaluable and demonstrates how little we know about what lies under our feet.