What do distant quasars have to do with improving GPS accuracy? A 2019 article from the NASA Technology Transfer Program explains: “In the 1960s, NASA used a network of radio telescopes and a technique called very large baseline interferometry (VLBI) to capture images of quasars in distant galaxies. In the following decade, scientists reversed the process to determine the precise locations of the telescopes, painting a picture of Earth’s shape and orientation in space. Today, an evolution of that technology supports another location-based system that has arguably become the world’s most important communication infrastructure: the Global Positioning System (GPS).” [Ariel Waldman]