> a nuclear submarine could use it to make an ultra-accurate map of the world based on variations in the gravitational constant g I believe in the book version

> a nuclear submarine could use it to make an ultra-accurate map of the world based on variations in the gravitational constant g I believe in the book version of the Hunt for Red October by Tom Clancy, they mention that the Soviets did something similar but using a magnetometer. Super cool to see the newest versions of this are going from sci-fi to fact.