https://ninkilim.com/articles/we_live_inside_an_electric_circuit/en.html
When people hear the phrase space weather, they might think of solar flares disrupting satellites or aurora shimmering in the polar night. At its core, though, space weather is nothing more exotic than the behavior of charged particles streaming outward from the Sun.
The Sun’s outer layers are a seething plasma: so hot that electrons and protons no longer remain bound in atoms but move freely. Like a colossal filament in a vacuum tube, the Sun constantly emits this electrically conductive fluid as the solar wind. It flows outward through the solar system at hundreds of kilometers per second, carrying with it electrons, protons, alpha particles, and tangled magnetic fields.
Spacecraft at the L1 point - a million kilometers upstream of Earth - measure the solar wind in real time. They tell us how many electrons, protons, and heavier ions are arriving, and how fast. Under quiet conditions, the wind tends to have a slight excess of electrons, so interplanetary space carries a faintly negative charge background.
When a coronal mass ejection (CME) bursts from the Sun, the balance shifts. Huge bubbles of plasma and magnetic field sweep through space and collide with Earth’s magnetic shield. At the poles, some of this energy funnels downward along magnetic field lines, exciting oxygen and nitrogen atoms into glowing curtains of green and red: the aurora borealis in the Northern Hemisphere, the aurora australis in the Southern.
Earth has been bathed in this environment for billions of years. Conductive bodies immersed in plasma do not remain neutral; they accumulate charge. Over geological time, Earth has settled into a slightly negative electrical potential relative to its space environment.
This realization is our transition from space to sky: if Earth is negative, and space above is bathed in electrons and protons, how does the charge balance play out in the atmosphere itself? The answer is the ionosphere.
The ionosphere begins around 50 km up and extends into the hundreds. There, solar ultraviolet light and incoming particles knock electrons free of atoms, leaving a dilute gas of ions. To us on the ground, the air seems an insulator. But with altitude, ionization increases rapidly, and conductivity rises by many orders of magnitude.
The ionosphere was discovered in the 1920s, not by physicists but by radio engineers. Edward Appleton and colleagues noticed that radio waves sometimes traveled far beyond the horizon. Signals were bouncing off a conductive layer high above - what we now call the E and F layers of the ionosphere. This “mirror in the sky” made global broadcasting possible, and Appleton’s work earned him a Nobel Prize.
But beyond radio, the ionosphere has deeper significance. Imagine Earth as a conductive sphere carrying negative charge, and the ionosphere as a positively charged shell tens of kilometers up. Between them lies the atmosphere: not a perfect vacuum, not a perfect insulator, but a leaky dielectric. Together they form a spherical capacitor, charged to about +250,000 volts.
At the ground, this potential appears as the fair-weather atmospheric electric field: about +100 to +300 volts per meter, directed downward. In other words, the positive ionosphere pulls electrons upward, leaving the surface relatively negative. Because air becomes more conductive with altitude, most of this voltage drop occurs in the lowest 10–15 km - the troposphere, where all clouds and weather reside.
In calm conditions this field is steady, modulated only by the global rhythm of all the world’s storms - a daily cycle called the Carnegie curve. This quiet baseline, however, sets the stage for the drama of thunderstorms.
Inside a growing cumulonimbus cloud, trillions of ice particles and droplets collide. Each carries ions: the H⁺ and OH⁻ constantly present in water. The ambient electric field biases how these charges move. Small ice crystals tend to acquire positive charge and are carried upward by updrafts, while heavier graupel collects negative charge and falls to mid-levels.
The result is a tripole structure:
This separation mirrors a famous 19th-century experiment. In 1867, Lord Kelvin - best known for the thermodynamic temperature scale - built a device using only dripping water, rings, and buckets. The Kelvin water dropper exploited tiny ionic imbalances in falling drops. With clever induction, those fluctuations reinforced until sparks thousands of volts long leapt from the apparatus.
Kelvin’s tabletop contraption was a thunderstorm in miniature. Clouds are simply larger versions of the same charge factory, powered by gravity, convection, and collisions.
Most lightning we see comes from the negative mid-level discharging to the ground. But sometimes the upper positive region releases its charge. These positive lightning strokes are far more powerful, carrying larger currents and reaching tens of kilometers sideways - the infamous “bolts from the blue.” Rare but deadly, they are the inverse of the fair-weather field: the cloud’s positive top discharging directly to the Earth.
Each thunderstorm thus acts as a generator, pumping positive charge upward to the ionosphere and negative charge downward to the ground. Collectively, Earth’s ~2,000 active storms maintain the global 250 kV potential, replenishing what would otherwise leak away. Thunderstorms are not just weather events; they are the power stations of the planet’s electric circuit.
For centuries lightning was thought to be confined below the cloud base. But the circuit runs both ways. Storms also discharge upward, into the ionosphere, sometimes all the way into near space.
In the 1990s, satellites looking for cosmic gamma-ray bursts detected something unexpected: millisecond flashes of gamma radiation from Earth itself. These Terrestrial Gamma-Ray Flashes (TGFs) are produced when storm-top electric fields accelerate electrons to near-relativistic speeds, slamming them into air molecules and emitting gamma rays. A thunderstorm becomes a natural particle accelerator, rivaling man-made machines.
Long before satellites confirmed this, high-altitude pilots whispered about strange lights: red glows, blue cones, halo-like rings above storms. U-2 pilots in the 1950s may have been among the first to see them, but their reports were dismissed as optical illusions. Only in the late 20th century did cameras catch them:
Together, these are Transient Luminous Events (TLEs) - the sky’s hidden lightning, connecting storms to the ionosphere. They prove thunderstorms are not local but global actors, injecting energy and particles upward, perturbing radio propagation, satellite orbits, even radiation belts.
We began with space weather as something imposed on Earth. Now we see the reverse: Earth itself generates space weather, through the work of its storms.
By now the outline is clear: Earth, ionosphere, and space are bound in a global electric circuit. Yet this topic falls awkwardly between disciplines.
The result is that atmospheric electricity slips through the cracks. Standard weather reports give temperature, pressure, wind, and humidity - but not the static atmospheric field, even though it can be measured with a simple field mill.
We already have models. Lightning networks (Blitzortung, ALDIS, EUCLID) show storm activity in real time by tracking sferics, the radio pulses of lightning. Why not build the same for static electric fields?
Such a network could:
Many observatories already measure atmospheric electricity, but the data is scattered and hidden. A coordinated global effort called GLOCAEM (Global Coordination of Atmospheric Electricity Measurements) was launched only a few years ago, linking together ~20–30 stations from Europe, Asia, Africa, and the Americas. Some of these sites - like the Conrad Observatory in Austria, Lomnický Štít in Slovakia, and Eskdalemuir in Scotland - have long histories of continuous potential-gradient monitoring.
But unlike lightning networks such as Blitzortung, these data streams remain largely in the hands of researchers. Real-time plots exist, but they are not widely publicized or designed for public use. For most people - even physics students - the atmospheric field is still invisible.
That is the gap: not measurement, but accessibility. What is needed is the translation of scientific archives into public dashboards and open APIs, the same way that sferic networks made storm activity something anyone could watch unfold live. A citizen-science layer on top of existing research networks could close the loop - turning hidden observatory charts into a living “fifth weather variable.”
We live inside an electrical circuit. The Earth is the negative plate, the ionosphere the positive, and thunderstorms the generators. Lightning is only the most visible symptom. Sprites, jets, gamma rays, and fair-weather currents are the rest.
Bringing this hidden dimension of weather into public view - by opening data and building networks - would complete our understanding of the sky. It would give us better forecasting tools, new insights into climate and health, and restore a sense of wonder: the realization that the world we walk on is not just spinning in space, but glowing, humming, and sparking inside a planetary-scale electric machine.