Scientists have detected the Earth’s ambipolar electric field for the first time

For the first time, scientists have successfully detected and measured an invisible electric field that envelops the Earth. The field, known as the ambipolar field, was first theorized more than 60 years ago, and its discovery marks a major advance in our understanding of Earth’s atmospheric dynamics. Glyn Collinson, an astronomer at NASA’s Goddard Space Flight Center, and his team made 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 ambipolar field was hypothesized to exist about 250 kilometers (155 miles) above the Earth’s surface, in the ionosphere, a region of the atmosphere ionized by solar and ultraviolet radiation. This field is created by the interaction of 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 maintains a balance between these particles, with electrons trying to escape into space and ions retreating toward 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 ascended to an altitude of 768.03 kilometers (477.23 mi) before returning to Earth with valuable data. The mission was intended to measure the weak changes in the electric potential associated with the ambipolar field. Despite the weak strength of the field, only a change of 0.55 volts was detected, comparable to the charge of a watch battery. This tiny measurement was enough to confirm the presence of the ambipolar field and its effects on the polar wind.

Significance of the discovery

The ambipolar field plays a crucial role in regulating the density and composition of the atmosphere. It helps control the height at which ions escape into space, which affects the overall atmospheric structure. Detecting this field provides insight into how Earth’s atmosphere remains charge neutral and how particles are swept away from the planet. It also affects the polar wind, an outflow of particles from Earth’s atmosphere that is observed near the poles.

Implications for future research

While the immediate findings are promising, this discovery is just the beginning. The broader implications of the ambipolar field are still being explored. Researchers are keen to understand how long this field has existed, how it affects atmospheric evolution, and what its potential impact is on life on Earth. Glyn Collinson stresses that measuring this field will allow scientists to ask new questions about Earth’s atmospheric processes and planetary science in general.

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 major step in planetary science, paving the way for future exploration and understanding of the forces that shape our world.