Could you really dig a hole to China?
Generations of American kids were told that if you dug deep enough you’d reach China. Here’s where you’d actually come out, and why nobody will ever make the trip.
If you grew up in the United States, someone probably told you that a deep enough hole in the backyard would come out in China. It’s a great image. It’s also wrong, by a few thousand kilometers.
Where a tunnel from the US really goes
The point directly opposite you on the globe, your antipode, is found by flipping your latitude from north to south and swinging your longitude around by 180°. Do that for the lower 48 states and almost every spot lands in the southern Indian Ocean, somewhere southwest of Australia.
- New York comes out about 1,000 km off the coast of Western Australia.
- Kansas, right in the middle of the country, comes out about 1,500 km from the nearest land, the remote French Southern and Antarctic Lands.
- Bermuda gets surprisingly close to dry land: its tunnel ends about 55 km off the coast of Western Australia, near Perth.
A few parts of the US do hit land. Hawaii comes out in the Kalahari in Botswana. The far north of Alaska comes out in Antarctica. See every state on our US states map.
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So who can dig to China?
To come out in China, you’d have to start in Argentina or Chile. Santiago, Córdoba, Rosario and Mendoza all tunnel straight through to China. Buenos Aires just misses: its tunnel ends in the Yellow Sea, about 130 km off China’s coast.
Even then, most of China’s exact opposite side is open water in the South Pacific. Only about a quarter of it is land. See the full breakdown on the Can you dig to China? page.
Fun fact: Córdoba, Spain and Hamilton, New Zealand are almost perfect opposites, only about 13 km off.
Why nobody will ever do it
Set geography aside and the trip is still impossible:
- Distance. A tunnel straight through the center is about 12,740 km long. The deepest hole humans have ever drilled, the Kola Superdeep Borehole, reached 12.3 km, about 0.2% of the way to the center.
- Heat. Rock gets hotter the deeper you go. The bottom of the Kola hole was already around 180 °C. The inner core is around 5,000–6,000 °C, about as hot as the surface of the Sun.
- Pressure. At the center, the pressure is about 3.6 million times the air pressure at the surface. No tunnel wall could survive it.
- Liquid metal. About 2,900 km down you’d hit the outer core, an ocean of molten iron and nickel more than 2,000 km deep.
The fun part: falling through
Physicists love this thought experiment anyway. Imagine a perfect tunnel with no air and no friction. Jump in and gravity pulls you faster and faster until you fly through the center, then slows you down until you pop out at the far end, just as you come to a stop.
The whole trip would take about 38 minutes. If Earth had the same density all the way through, it would take about 42 minutes. Because the dense core pulls harder than the light rock above it, the real trip is a few minutes faster. (Here’s the full physics.)