NASA has confirmed the existence of an ambipolar electric field in Earth's atmosphere, a force that has been theorised for decades. The research, published in Nature, suggests this field plays a role comparable to gravity and magnetism in shaping atmospheric behaviour.
Since the 1960s, scientists have observed cold air particles escaping Earth’s upper atmosphere at supersonic speeds, a phenomenon known as the polar wind. The process lacked a clear explanation until researchers identified the influence of a weak electric field.
On 11 May 2022, NASA's Endurance mission launched a sounding rocket from Norway to measure this field. At an altitude of 477 miles (768 km), the instruments recorded a steady electric potential of 0.55 volts, confirming its existence.
This small voltage is enough to lift hydrogen and oxygen ions into space, overcoming Earth’s gravity. The field acts as a slow but continuous force, allowing light elements to escape over time.
NASA’s data showed a 271% increase in ion density at higher altitudes, indicating that the electric field actively contributes to atmospheric loss. The process does not rely on solar radiation or heat but operates steadily over long periods.
This gradual escape of particles influences the composition of Earth's atmosphere over geological timescales. Scientists believe the ambipolar field has been shaping atmospheric conditions for millions or even billions of years.
If Earth has an ambipolar electric field, other planets with atmospheres, such as Mars and Venus, may have similar mechanisms affecting their atmospheric stability. Understanding this process could help scientists assess planetary habitability beyond Earth.