Earth’s surface barely scratched: Why no one’s ever reached the planet’s core

Produced by: Manoj Kumar

Crust Limit

The deepest humans have drilled is 12.2 km at the Kola Superdeep Borehole in Russia—less than 0.2% of the way to Earth’s center. The crust alone extends tens of kilometers.

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Heat Barrier

Temperatures at Kola reached 180°C. At the core, it’s around 6,000°C—comparable to the Sun’s surface. Most materials and electronics can’t survive long under those conditions.

Pressure Wall

The deeper you go, the higher the pressure. At the core, it’s over 3 million times atmospheric pressure—crushing anything we currently know how to build.

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Kola Roadblock

Drilled between 1970 and 1989, the Kola project had to stop despite decades of work due to rock instability, temperature extremes, and equipment failure—not lack of will.

Flowing Rock

Deep Earth rock isn’t solid like surface stone—it flows, shifts, and collapses under pressure. That means drilled holes often close up or collapse from the stress.

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Energy Sink

Deeper drilling requires exponentially more energy and resources. Even narrow boreholes cost hundreds of millions—and deliver diminishing returns past certain depths.

No Risk Yet

Concerns about “drilling too deep” triggering disasters are hypothetical. We’ve never approached magma chambers or tectonic boundaries at sufficient depth to cause such events.

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Seismic Solution

Instead of digging, scientists use seismic waves from earthquakes. Changes in wave speed and direction help map Earth’s internal layers, including the molten outer core and solid inner core.

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Core Modeling

With lab tools like diamond anvil cells and computer simulations, geophysicists replicate deep-Earth conditions to study materials and make educated guesses about what lies below.

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