Invisible electric field discovered surrounding Earth is "as crucial as gravity"

Observations from a NASA suborbital rocket have enabled an international group of experts to measure a global electric field that surrounds Earth for the first time ever.

According to scientists, this ambipolar electric field is thought to be just as crucial to Earth as gravity and magnetism.

The finding stems from data captured by NASA’s Endurance mission, which targeted a zone in the upper atmosphere associated with the escape of air into space.

Earth’s ambipolar electric field

Scientists first proposed over half a century ago that this planet-wide field played a part in shaping how particles leave Earth’s atmosphere through the North and South Poles.

The measurement of this phenomenon, called the ambipolar electric field, helps reveal the forces behind what researchers have described as the “polar wind.”

Glyn Collinson is the principal investigator of Endurance at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the paper recently published in the journal Nature.

Puzzling polar outflow

In the late 1960s, spacecraft over Earth’s poles detected a steady trickle of air streaming away from our planet. Theorists called it the “polar wind” and wondered how cold particles could travel at supersonic speed without apparent heating.

Scientists suspected an undetected force was at work. “Something had to be drawing these particles out of the atmosphere,” said Collinson.

Many expected some outflow from the Sun’s influence, but the persistent polar wind suggested an additional explanation.

Researchers reasoned that a subtle electric field might be the culprit, but previous instruments could not detect it.

The Endurance mission was designed to settle the debate once and for all. By focusing on the upper atmosphere where these flows become most pronounced, the team hoped to see how weak charges can affect enormous scales.

How to find Earth’s electric field

The mission team settled on Svalbard, a Norwegian archipelago, as the launch site.

“Svalbard is the only rocket range in the world where you can fly through the polar wind and make the measurements we needed,” said Suzie Imber, a space physicist at the University of Leicester, UK, and co-author of the paper.

The region’s location made it possible to intersect key pathways where energized particles exit Earth’s protective layers.

On May 11, 2022, Endurance soared to a peak of 477.23 miles (768.03 kilometers) before returning to the Greenland Sea 19 minutes later. Throughout a 322-mile stretch of its ascent, the rocket registered a mere 0.55 volts of electric potential.

“A half a volt is almost nothing – it’s only about as strong as a watch battery,” Collinson said. “But that’s just the right amount to explain the polar wind.”

The extremely thin air at those altitudes, combined with the rocket’s specialized instruments, made it possible to witness phenomena that remained undetected for decades.

Earth, electric fields, and supersonic winds

Hydrogen, the main ingredient in this outflow, experiences a pull from this newly confirmed field that is 10.6 times stronger than Earth’s gravity.

“That’s more than enough to counter gravity – in fact, it’s enough to launch them upwards into space at supersonic speeds,” said Alex Glocer, Endurance project scientist at NASA Goddard and co-author of the paper.

Oxygen ions also get lifted, weighing half as much when immersed in that slight voltage. These movements occur without requiring noticeable heating, which puzzled researchers until now.

Endurance’s data showed an increase in the ionosphere’s density at higher altitudes by 271%, suggesting that this faint electric field steadily pushes substantial amounts of our air beyond Earth’s boundary.

“It’s like this conveyor belt, lifting the atmosphere up into space,” Collinson added.

Researchers believe this interplay between charged particles and electric fields has existed for much of Earth’s past, quietly altering the composition of the sky overhead.

Atmospheric escape and particle loss

Atmospheric escape happens on any world with enough energy to lose particles over time. On Earth, the puzzle centers on how both hot and relatively cool ions break free.

While solar radiation was long assumed to be the main culprit, the newly measured ambipolar field offers an additional key. It acts across vast distances, even when the individual charges involved are incredibly weak.

By studying these subtle processes, scientists gain clues about the evolution of gases that form our protective envelope.

Over millions of years, small but persistent leaks could change how the atmosphere balances essential ingredients like oxygen and hydrogen.

Piecing together these details helps reveal how our planet has maintained conditions suitable for life.

What does all of this mean?

To sum it all up, researchers solved the long-standing puzzle of how cold ions break free from the atmosphere by measuring this slight voltage across Earth’s poles.

Scientists see this field as an important key for unraveling how other planets lose air into space. The same physical processes may apply to places like Mars and Venus, where subtle electric forces could be influencing the thickness and composition of their skies.

Studying these effects on different worlds might even shed light on the potential for life elsewhere in our solar system.

Experts emphasize that this newly confirmed electric field surrounding Earth stands alongside magnetism and gravity as a fundamental feature of our planet.

“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.”

The full study was published in the journal Nature.

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