Comparing models to reality (IMAGE) American Geophysical Union Caption Here, the researchers compare the observed polar motion (red arrow, “OBS”) to the modeling results without (dashed blue arrow) and with (solid blue arrow) groundwater mass redistribution. The model with groundwater mass redistribution is a much better match for the observed polar motion, telling the researchers the magnitude and direction of groundwater’s influence on the Earth’s spin. Credit Seo et al. (2023), Geophysical Research Letters Usage Restrictions Credit to paper License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.