NASA Wants to Track Earth’s Gravity With a Cloud of Floating Atoms in Space

Buckle up, nerds: NASA is building the first quantum gravity sensor for space—a suitcase-sized instrument that could soon be measuring everything from subterranean water to hidden reserves of petroleum, all by watching how clouds of atoms act under the force of gravity. Researchers at NASA’s Jet Propulsion Laboratory (JPL), along with several partners, are developing the project, dubbed the Quantum Gravity Gradiometer Pathfinder (QGGPf). As its name indicates, QGGPf is a gravity gradiometer, which measures how the acceleration of one object compares to that of another nearby object; the difference in the objects’ acceleration corresponds to gravitational strength acting on each object. When gravity is stronger, the objects—a.k.a. test masses—fall faster. Earth’s gravity isn’t constant—it changes subtly all the time as mass shifts around the planet. Geological processes like tectonic activity, glaciers calving, or aquifers draining can slightly nudge gravitational forces in one area o ... Read full article.