NASA develops ultra-precise method to track millimeter shifts in Earth’s mass center
NASA researchers have quantified seasonal millimeter-scale movements of Earth’s center of mass using laser-ranged satellites, GPS and gravity data.
Geoscientist Donald Argus and colleagues at JPL introduced a refined approach for monitoring Earth’s center of mass, which oscillates a few millimeters as seasonal water, ice and atmospheric mass relocate. The method combines laser ranging of the 1976 and 1992 LAGEOS satellites with GPS tracking and data from low-Earth-orbit satellites, while also modeling crustal deformation caused by shifting loads. This reduces the previous uncertainty gap of 0.27 inches between 2017 and 2023 estimates.
The analysis attributes the annual shift to three reservoirs—oceans, atmosphere and continental water—with notable contributions from March snow in North America, April Amazon river water, November Southeast Asian monsoon, and August-October Pacific meltwater. Seasonal atmospheric density moves the mass center toward Arabia in winter and toward South America in summer. Findings match independent GRACE-FO gravity observations and support the upcoming GRACE-C mission planned for late 2028. Accurate knowledge of these tiny shifts underpins global navigation, mapping and precision agriculture.
Why it matters
Accurate tracking of Earth’s shifting mass improves satellite navigation and climate-related measurements worldwide.
In this story
