NASA study reveals seasonal shifts in Earth's center of mass

New research led by NASA’s Jet Propulsion Laboratory (JPL) has provided a more precise understanding of how Earth’s center of mass, or geocenter, shifts due to the movement of water, ice, and the atmosphere. Using a hybrid technique that combines GPS data with low-orbit satellite tracking, scientists found that these seasonal shifts are approximately half of what previous estimates suggested.

The redistribution of mass is driven by three primary factors: oceans, the atmosphere, and continental water. Significant seasonal movements occur due to snow accumulation in the Northern Hemisphere, ocean current changes, and heavy rainfall. For instance, during the Amazon Basin's rainy season in April, the accumulation of approximately 2,400 gigatonnes of water can shift the Earth's center of mass by about 2.2 millimeters toward South America.

While these millimeter-scale oscillations are imperceptible to humans, they are critical for high-precision technologies. Accurate geocenter data is essential for satellite navigation, GPS accuracy, digital mapping, and altitude calculations, as satellites orbit the planet's center of mass rather than its geometric center.