Scientists have discovered an invisible, ambipolar electric field around Earth for the first time, new study reveals

For the first time, scientists have successfully detected and measured an invisible electric field surrounding Earth. This field, known as the ambipolar field, was first theoretically described more than 60 years ago, and its discovery represents a significant advance in our understanding of the dynamics of Earth’s atmosphere. Glyn Collinson, an astronomer at NASA’s Goddard Space Flight Center, and his team achieved the breakthrough, opening up new avenues for studying how such fields affect planetary atmospheres and potentially shape other celestial bodies.

Understanding the ambipolar field

The hypothesis posits that an ambipolar field exists about 250 kilometers (155 miles) above Earth’s surface, in the ionosphere—a region of the atmosphere ionized by sunlight and ultraviolet radiation. The field is created by interactions between negatively charged electrons and positively charged ions. When ultraviolet rays ionize atmospheric atoms, they create a mix of free electrons and ions. The ambipolar field acts to balance these particles, with electrons trying to escape into space and ions trying to return to Earth, creating a stabilizing force.

How the field was detected

The field was detected by the Endurance rocket, which was launched in May 2022. The rocket rose to an altitude of 768.03 km (477.23 miles), then returned to Earth with valuable data. The mission aimed to measure the weak changes in electric potential associated with the ambipolar field. Despite the weak field strength, only a change of 0.55 V was detected, comparable to the charge of a watch battery. This small measurement was enough to confirm the presence of the ambipolar field and its effect on the polar wind.

The significance of the discovery

The ambipolar field plays a key role in regulating the density and composition of the atmosphere. It helps control the height at which ions escape into space, affecting the overall structure of the atmosphere. Detecting this field provides insight into how Earth’s atmosphere maintains charge neutrality and how molecules are transported away from the planet. It also affects the polar wind—the outflow of molecules from Earth’s atmosphere observed at the poles.

Implications for future research

While the immediate results are promising, this discovery is just the beginning. The broader implications of the ambipolar field are still being explored. Scientists want to understand how long the field has been around, how it affects atmospheric evolution, and what its potential impact is on life on Earth. Glyn Collinson emphasizes that measuring the field allows scientists to ask new questions about Earth’s atmospheric processes and planetary science more broadly.

With this breakthrough, scientists can now delve deeper into the fundamental mechanisms that govern Earth’s atmosphere and potentially apply these insights to other planets with atmospheres. The discovery of the ambipolar field represents a significant step forward in planetary science, paving the way for future research and understanding of the forces that shape our world.