Entry 06 · Trilogy 2 · Planetary geometry
The 42-Minute Earth: The Planet’s Heartbeat
In 1966 Paul Cooper asked a simple question. If one could drill a tunnel through Earth, how long would the fall take?
The answer, in the simple gravity-tunnel problem, is about 42 minutes, the same as a low-orbit half-period in the same toy model.
It is a calculation, not a pulse you can auscultate. The Book keeps the toy model honest and still lets the heartbeat image stand as living language.