Earth’s center of mass is moving, and scientists just found something surprising

Key Points:

• Earth's center of mass, crucial for GPS and satellite navigation, shifts annually by several millimeters due to factors like snowmelt, ocean currents, and air movement, but new research shows this shift is about half as large as previously estimated eight years ago.
• Previous estimates varied significantly, with a 7-millimeter discrepancy between 2017 and 2023 measurements, nearly as large as the motion being measured, prompting a new study led by NASA's Jet Propulsion Laboratory to refine the data.
• The study improved accuracy by incorporating GPS data, low-orbit satellite tracking, and accounting for Earth's crust bending under water and ice weight, allowing a detailed breakdown of seasonal mass shifts caused by snow, rain, ocean changes, and atmospheric pressure.
• Seasonal shifts include snow accumulation pushing the center of mass northward in March, Amazon basin rainfall moving it southward in April, and ocean swelling in the South Pacific during fall, with atmospheric density changes also contributing to the movement.
• Accurate knowledge of these shifts is vital for precise navigation, sea level monitoring, and mapping technologies, with the study's findings published in Geophysical Journal International highlighting the importance of refining Earth's reference systems.