NASA Refines Earth’s Center‑of‑Mass Measurements, Reducing Uncertainty to Fractional Inches

NASA’s Jet Propulsion Laboratory has unveiled a new ultraprecise satellite‑tracking method that pinpoints Earth’s center of mass with a precision of fractions of an inch. By combining GPS data with observations from low‑Earth‑orbit satellites and accounting for crustal deformation, the technique halves the previously estimated seasonal swing of the planet’s mass center. The study, published in Geophysical Journal International, shows that snow buildup in North America and Eurasia shifts the center about 3 mm toward the North Pole, while Amazon rainwater moves it 2. 2 mm toward South America, and monsoon water adds a smaller shift in Southeast Asia. These movements, driven by oceans, atmosphere, and continental water, are now measured with millimeter‑scale accuracy, matching GRACE‑FO observations. The refined reference point will enhance satellite navigation, elevation measurements, and global positioning systems used in shipping, agriculture, and mapping.