Kola Superdeep Borehole.
The deepest hole in the world is under this welded-shut cap in an abandoned structure in Russia. Called the Kola Superdeep Borehole, this 9-inch diameter hole goes deeper than the bottom of the sea.
Read that again: This hole goes deeper than then lowest known point in the ocean. Challenger Deep, at the bottom of the Mariana Trench, is 36,201 feet below sea level. The Kola Borehole goes over 4,000 feet deeper.
All of this of course begs the question: Why dig such a deep hole? Russian scientists hoped to learn more about the continental crust, which is the layer of rock that forms the continents and their continental shelves. They made it 7.6 miles, or about a third of the way through the Baltic Shield crust. (Keep in mind that the distance to the center of the Earth is 3,958 miles, so in comparison, it barely pricked the surface.)
Drilling began in 1970. A 200-foot tall superstructure was built to house the enormous pipes that made up the “drill string” which connected the drill to the surface. As the drill reached lower and lower, sections of pipe were strung together like the world’s longest necklace and then lowered into the hole. In 1984, a 3-mile section of this drill string twisted off and ended up blocking the hole. They had to start again with a new hole four miles down.
Some of the cool things that they discovered included water below an impermeable layer of rock (formed from oxygen and hydrogen molecules being literally squeezed out of minerals) and a high quantity of hydrogen gas. They also discovered fully intact fossils of microscopic single-cell plankton, over 2 billion years old!
In 1992 drilling finally stopped, as they encountered higher-than-expected temperatures at this depth (up to 356 degrees Fahrenheit).
With the end of the Soviet Union in 1995 came the abandonment of the site. Garbage is now strewn across one of the greatest human achievements of the 20th Century.
If you do ever visit the Kola Borehole, please don’t open it up. You wouldn’t want to drop anything important down there.
Read that again: This hole goes deeper than then lowest known point in the ocean. Challenger Deep, at the bottom of the Mariana Trench, is 36,201 feet below sea level. The Kola Borehole goes over 4,000 feet deeper.
All of this of course begs the question: Why dig such a deep hole? Russian scientists hoped to learn more about the continental crust, which is the layer of rock that forms the continents and their continental shelves. They made it 7.6 miles, or about a third of the way through the Baltic Shield crust. (Keep in mind that the distance to the center of the Earth is 3,958 miles, so in comparison, it barely pricked the surface.)
Drilling began in 1970. A 200-foot tall superstructure was built to house the enormous pipes that made up the “drill string” which connected the drill to the surface. As the drill reached lower and lower, sections of pipe were strung together like the world’s longest necklace and then lowered into the hole. In 1984, a 3-mile section of this drill string twisted off and ended up blocking the hole. They had to start again with a new hole four miles down.
Some of the cool things that they discovered included water below an impermeable layer of rock (formed from oxygen and hydrogen molecules being literally squeezed out of minerals) and a high quantity of hydrogen gas. They also discovered fully intact fossils of microscopic single-cell plankton, over 2 billion years old!
In 1992 drilling finally stopped, as they encountered higher-than-expected temperatures at this depth (up to 356 degrees Fahrenheit).
With the end of the Soviet Union in 1995 came the abandonment of the site. Garbage is now strewn across one of the greatest human achievements of the 20th Century.
If you do ever visit the Kola Borehole, please don’t open it up. You wouldn’t want to drop anything important down there.