For the first time, scientists have successfully detected and measured an invisible electric field enveloping Earth. This field, known as the ambipolar field, was first theorized more than 60 years ago and its discovery marks a significant advance in our understanding of Earth’s atmospheric dynamics. Glyn Collinson, an astronomer at Agency’s Goddard Space Flight Center, and his team have made this breakthrough, opening new avenues for studying how these fields influence planetary atmospheres and potentially shape other celestial bodies.
Understanding the ambipolar field
The ambipolar field is hypothesized to exist about 250 kilometers (155 mi) above the Earth's surface, within the ionosphere, a region of the atmosphere ionized by solar and ultraviolet radiation. This field arises due to the interaction between negatively charged electrons and positively charged ions. When UV rays ionize atmospheric atoms, they create a mixture of free electrons and ions. The ambipolar field acts to balance these particles, as electrons try to escape into space and ions head toward Earth, creating a stabilizing force.
How the field was detected
The field was detected by the Endurance rocket, which launched in May 2022. The rocket climbed to an altitude of 768.03 kilometers (477.23 mi) before returning to Earth with valuable data. The mission aimed to measure the weak electrical potential changes associated with the ambipolar field. Despite the weak intensity of the field, only a change of 0.55 volts was detected, comparable to the charge in a watch battery. This tiny measurement was enough to confirm the presence of the ambipolar field and its effects on the polar wind.
Importance of the discovery
The ambipolar field plays a crucial role in regulating the density and composition of the atmosphere. It helps control the altitude at which ions escape into space, affecting the overall atmospheric structure. Detecting this field provides insight into how Earth's atmosphere maintains charge neutrality and how particles are carried away from the planet. It also affects the polar wind, an outflow of particles from Earth's atmosphere observed at the poles.
Implications for future research
Although the immediate results are promising, this discovery is just the beginning. The broader implications of the ambipolar field are still being explored. Researchers are interested in understanding how long this field has been present, how it influences atmospheric evolution, and its potential impact on life on Earth. Glyn Collinson highlights that measuring this field allows 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 this knowledge to other planets with atmospheres. The discovery of the ambipolar field represents a significant step in planetary science, paving the way for future exploration and understanding of the forces that shape our world.