There are a few things in this cosmos that are truly universal. The fundamental laws that govern reality apply everywhere and at all times. The fundamental constants that determine the masses, charges, and interaction strengths between particles are universal as well. Today, there are four known fundamental forces: electromagnetism, gravitation, the strong nuclear force, and the weak nuclear force, plus whatever “dark energy” ultimately turns out to be. Electromagnetism is, in many ways, the best-measured of all the fundamental interactions, and its strength is known to better than 1-part-in-a-billion from precision laboratory experiments. But gravitation, despite being the first fundamental force ever discovered, remains only extremely poorly known: to only 1-part-in-a-few-thousand, where the uncertainty shows up in the fourth significant digit. Part of the reason is due to its incredible weakness; the gravitational attraction between two electrons is more than forty orders of magnitude smaller than the electrostatic repulsion between two electrons. But part of the reason is that even with our most precise and accurate measurements that lead to a determination of the gravitational …