@absurdlyexact: Dig a hole straight through the Earth and jump in. The textbook answer is 42 minutes, and it doesn't matter where the tunnel goes. The real Earth is faster: 38 minutes 11 seconds straight through, because its iron core is about five times denser than the rock on top. We computed the numbers from the Preliminary Reference Earth Model (PREM), a model of Earth's density built from seismic data. Our result matches Alexander Klotz's 2015 paper. The London to Paris tunnel is drawn larger than scale. Sources A. R. Klotz, "The gravity tunnel in a non-uniform Earth", Am. J. Phys. 83, 231 (2015): https://arxiv.org/abs/1308.1342 A. M. Dziewonski & D. L. Anderson, "Preliminary reference Earth model", Phys. Earth Planet. Inter. 25, 297 (1981) #shorts #physics #science #whatif

Absurdly Exact

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Wednesday 07 October 2026 19:54:14 GMT