A faint electric field has been detected in Earth's atmosphere, confirming a long-held scientific theory. This ambipolar electric field, measured at just 0.55 volts, may play a crucial role in shaping atmospheric evolution and supporting life. Glyn Collinson, an atmospheric scientist at NASA's Goddard Space Flight Center, led the Endurance rocket mission, which successfully captured this measurement in May 2022 above Svalbard, Norway.
The field is believed to explain the polar wind phenomenon observed for decades. When sunlight interacts with upper-atmospheric atoms, it causes negatively charged electrons to escape into space while heavier, positively charged oxygen ions remain. To maintain electrical neutrality, the faint electric field forms, preventing electron loss and providing energy to lighter ions like hydrogen, which can then escape Earth's gravity and contribute to the polar wind.
This discovery may have significant implications for understanding planetary habitability. David Brain, a planetary scientist at the University of Colorado Boulder, suggests that examining how such electric fields vary across planets could clarify why Earth remains habitable compared to Mars and Venus. While both Mars and Venus possess electric fields, their lack of a global magnetic field has led to substantial atmospheric loss, potentially altering their climates.
NASA has approved a follow-up mission with the rocket Resolute, expected to launch soon. Collinson emphasizes that further research into planetary electric fields could provide insights into the conditions that allow Earth to support life while other planets do not.