"Something had to be drawing these particles out of the atmosphere."
Ambipolar Seltzer
An international team of scientists at NASA and other institutions say they've discovered a weak, planet-wide electric field wrapping the Earth that was first hypothesized by researchers decades ago.
As detailed in a new paper published in the journal Nature, the team used observations from NASA's Endurance mission to make its discovery. The suborbital rocket launched in May 2022, reaching an altitude of 477 miles while measuring minute changes in the electric charge.
The discovery of the Earth's "ambipolar electric field" may have played an important role in our planet's evolution and could help us in the search for remote and potentially hospitable planets beyond our star system.
Electric Feel
The energy field was first hypothesized by researchers in the late 1960s. At the time, spacecraft crossing our planet's poles detected an outflow of charged particles, a phenomenon scientists later called the "polar wind."
These particles were cold despite traveling at supersonic speeds, puzzling scientists at the time.
"Something had to be drawing these particles out of the atmosphere," said lead author and Endurance principal investigator Glyn Collinson in a NASA statement.
Thanks to technical limitations, detecting the hypothesized electric field remained impossible — until now.
NASA's Endurance rocket launched a few hundred miles from the North Pole in an archipelago called Svalbard to give the team the best chance of finding proof of this field.
"Svalbard is the only rocket range in the world where you can fly through the polar wind and make the measurements we needed," said coauthor and University of Leicester space physicist Suzie Imber in a statement.
The rocket's instrument needed to be extremely sensitive to changes in the electric potential.
"A half a volt is almost nothing — it’s only about as strong as a watch battery," Collinson explained. "But that’s just the right amount to explain the polar wind."
The team found that particles were launched into space at supersonic speeds, experiencing an outward force of over ten times the pull of gravity.
The scientists suggest that the ambipolar field enhances the far edge of the Earth's ionosphere, a protective barrier of electrons that ward off much of the Sun's radiation in the upper atmosphere.
The findings also hint at the presence of similar electric fields wrapped around other planets like Venus and Mars.
"Any planet with an atmosphere should have an ambipolar field," Collinson said. "Now that we’ve finally measured it, we can begin learning how it’s shaped our planet as well as others over time."
More on the ionosphere: NASA Discovers Strange Spectral Formations High Over the Earth
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