Geomagnetic storms caused by solar wind might be more extreme than previously thought

The severity of geomagnetic storms — magnetic disturbances in Earth’s outer atmosphere — is widely understood to reach an upper limit as the strength of the solar wind increases. But this upper limit is an illusion that results from uncertainty in the measurement of solar-wind strength as the true value regresses towards the mean. Regression to the mean explains away the apparent limit to geomagnetic disturbances linked to strong solar winds.