THE SHORT ANSWER
The deepest hole ever dug, the Kola Superdeep Borehole, goes down 12,262 m. That sounds deep, but the centre of the Earth is 6,371 km below us, so we've dug about 0.2% of the way.
Big facts, for scale
- The deepest mine, Mponeng in South Africa, goes over 4 km down, and the rock there can reach about 66 °C.
- The Kola hole in Russia is only about 23 cm wide, about as wide as a dinner plate. Drilling stopped in 1992 when the rock reached about 180 °C.
- If you could drill straight through the planet and jump in, the fall would take about 38 minutes.
- The inner core is about as hot as the surface of the Sun: roughly 5,400 °C, crushed under more than 3 million times the air pressure we feel.
Watch the episode
Tiny Human vs. the Earth's Core goes out on TikTok, Instagram, Facebook and X. Times are shown in yours.
For grown-ups and teachers
Great for primary units on Earth's structure. Ask: if the Earth were an apple, how thick would the part we've dug through be? (Thinner than the skin.) Why does it get hotter as you go down?
Sources
- NASA: Earth facts (the Earth's radius, 6,371 km)
- Kola Superdeep Borehole drilling records (USSR, 1970–1992): 12,262 m
- Klotz, "The gravity tunnel in a non-uniform Earth", American Journal of Physics, 2015 (about 38 minutes)
- Inner-core temperature: most estimates fall between about 5,000 and 6,000 °C
Facts last checked 4 November 2026. Tiny Human's art and voices are made with AI tools; every fact is checked by a person against the sources above.
