Dr Charles Bruce was a specialist in high-voltage electrical engineering and a Fellow of the Royal Astronomical Society. In the 1940s, he advanced a remarkable proposal that remains largely overlooked by mainstream astronomy: that many energetic phenomena in space are electrical in nature.

Bruce identified cosmic jets, solar flares, magnetic fields, and extreme temperatures as manifestations of electrical discharge processes. In doing so, he offered an early and important foundation for the electrodynamic view of the universe.

"And even if one regards the electric fields as merely another postulate, it has the great advantage that it is the one postulate which, in my view, renders all the others unnecessary."
C. E. R Bruce, Electric Fields in Space, Penguin Science, 1968

Bruce also interpreted the striking bipolar planetary nebula shown in the heading image above as an electrical phenomenon.

Don Scott is a retired Professor of Electrical Engineering with a long-standing interest in astronomy and cosmology.

Published in late 2006, The Electric Sky presents the principles of plasma cosmology and the electrodynamic view of the universe in a clear and accessible style. Combining sound science with straightforward explanations, it is a book that can be appreciated by both newcomers and experienced readers alike. It also provides a thoughtful challenge to the conventional view that gravity alone is responsible for shaping the cosmos.

Update (2022): Don Scott's latest book, The Interconnected Cosmos, is also available.

One of the most accessible laboratory analogues for compact energetic behaviour in space is the plasma focus device (often referred to as a "plasma gun"). In such a device, a bank of capacitors drives a discharge between coaxial electrodes, forming a self-organised plasma structure called a plasmoid. Under the right conditions, these plasmoids collapse and emit tightly collimated plasma flows along the axis.

This behaviour — filaments, pinches, plasmoids and jets — is a natural outcome of electromagnetic structure in plasmas, and is observed across scales from laboratory devices to astrophysical jets.

"Active galactic nuclei (AGNs) release vast amounts of energy, whose ultimate source is a supermassive black hole in the galactic nucleus. In so-called radio-loud AGNs, two relativistic jets of plasma emanate from the nucleus, presumably along the rotational axis of the black hole."
Denise C. Gabuzda, Matt Nagle, Naomi Roche — The Jets of AGN as Giant Co-axial Cables

Even within mainstream astrophysics, plasma jets are recognised as fundamental structures. What differs is the interpretation of their source.

For a fuller discussion of how plasma focus behaviour, plasmoids, and electromagnetic structure relate to the conventional concept of black holes — and why this matters for interpreting compact energetic objects in the sky — see:

Black Holes — Plasma Focus and the Problem of Interpretation

Understanding plasma mechanisms is a key part of interpreting the true nature of compact energetic structures in the universe.

Advances in astronomical imaging have revealed remarkably faint structures linking galaxies within the Virgo Cluster. Researchers describe them as cocoons, plumes, and streamers — delicate features that appear to trace previously unseen connections between neighbouring galaxies.

From the perspective of plasma cosmology, these structures are particularly intriguing. They resemble the filamentary plasma sheaths and Birkeland currents long predicted by electrodynamic models of the universe. Could these observations represent large-scale plasma circuits linking galaxies across intergalactic space?

In laboratory plasmas, the pinch effect naturally organises current-carrying plasma into filaments. These filaments can attract, repel, twist around one another, and transport energy over great distances. Plasma cosmology proposes that similar processes may operate on vastly larger scales, influencing the formation and evolution of galaxies.

If so, the faint structures now being observed may be more than streams of diffuse gas. They could offer a glimpse of an interconnected universe in which galaxies are linked not only by gravity, but also by electromagnetic processes.

NASA's Interstellar Boundary Explorer (IBEX) has revealed another unexpected feature at the edge of our solar system. Researchers discovered a narrow "ribbon" of highly energetic particles encircling the heliosphere — a structure that was not anticipated by conventional models and remains the subject of ongoing investigation.

From Physics World, October 2009:

"The instruments measure and count particles known as energetic neutral atoms. These arise from an area called the interstellar boundary. This zone, undetectable by normal telescopes, is where electrically charged particles flowing from the sun, called the solar wind, pass far beyond the planets and plow into the gas and dust of the larger galaxy ... We expected to see small, gradual spatial variations at the interstellar boundary,” McComas told physicsworld.com, a website of the London based Institute of Physics. Scientists think the finding doesn’t fit with the accepted model of the heliosphere, thought to be shaped like a com­et by the collision of the outgoing solar wind and a greater galactic wind."

Within the plasma cosmology framework, however, such ribbon-like structures are not necessarily unexpected. They may be interpreted as manifestations of large-scale electrical currents and filamentary plasma interactions. From this perspective, the IBEX ribbon could represent evidence of our solar system's electrical connection with the surrounding galactic environment.

Whether this interpretation ultimately proves correct remains a matter for continued observation and investigation. Even so, discoveries such as the IBEX ribbon remind us that nature is under no obligation to conform to our theoretical expectations. When observations challenge accepted models, alternative explanations deserve careful consideration.

The discovery of Herbig–Haro objects, sometimes described as “jetted stars”, continues to present intriguing questions for astronomers. The Astronomy Picture of the Day for 3 February 2006 observed:

“Though such energetic outflows are well known to be associated with the formation of young stars, the exact cause of the spiralling structures apparent in this case is still mysterious.”

Why should enormous jets of gas remain so remarkably narrow and coherent over distances of many light years? Why do so many exhibit spiralling filaments, regularly spaced “beads”, and characteristic kink or sawtooth instabilities?

From the perspective of plasma physics, these are natural questions to ask.

In the near vacuum of space, an unconfined stream of gas would be expected to disperse rapidly. Yet plasma carrying an electric current generates its own magnetic field, allowing it to become self-confining and self-organising. Laboratory plasmas routinely display the same kinds of filamentation, spiralling, beading, and kink instabilities observed in many astrophysical jets.

This is not merely a laboratory analogy. In 2011, Kronberg and colleagues reported the first direct determination of a galactic-scale electric current, measuring a current of approximately 10¹⁸ amperes flowing along the kiloparsec-scale jet of the galaxy 3C303. Their analysis concluded that the jet's energy flow was predominantly electromagnetic.

Could these similarities be telling us something important?

Plasma cosmology suggests that such structures may not be incidental, but signatures of electromagnetic processes operating on a cosmic scale. If so, gravity alone may not provide the whole story of how these remarkable objects form and remain stable over such immense distances.

As Hannes Alfvén repeatedly warned, elegant mathematics is no guarantee that nature will behave accordingly:

“The underlying assumptions of cosmologists today are developed with the most sophisticated mathematical methods and it is only the plasma itself which does not ‘understand’ how beautiful the theories are and absolutely refuses to obey them.”

Electrical circuits are often explained using fluid analogies. Current becomes water flowing through a pipe, voltage becomes pressure, and electrons become particles carried along with the stream.

These analogies are useful — up to a point.

The difficulty is that electrical energy does not simply travel through a wire in the way water travels through a pipe. The electrons within a conductor have a comparatively slow drift velocity, while changes in the electromagnetic field propagate through a circuit at a substantial fraction of the speed of light.

The distinction is captured mathematically by the Poynting vector, named after the English physicist John Henry Poynting. It describes the direction and rate of electromagnetic energy flow. In a simple circuit, the energy is associated with the electric and magnetic fields in and around the conductors and is directed into components where that energy is transferred, stored, or dissipated.

The wire therefore guides and constrains the electromagnetic interaction, but it should not be imagined simply as a pipe carrying electrical energy inside it.

"The energy merely streams round the outside of the conductor..."
John Henry Poynting, 1884

The familiar conveyor-belt analogy for electrons can also be useful. A small movement of charge at one point in a circuit can be associated with a rapid effect elsewhere, even though the individual electrons themselves drift slowly. But, like the water-pipe analogy, the conveyor belt remains only an analogy.

When a circuit branches, how does the electrical energy "know" which path to follow — the electrical equivalent of deciding whether a signal travels to a finger or a toe? Individual electrons make no such decision. As electromagnetic disturbances propagate through the network, the geometry, resistance, capacitance, inductance and other electrical properties of the circuit determine how fields, currents and energy are distributed between the branches.

The behaviour is therefore a property of the electromagnetic system as a whole, not a procession of individual electrons finding their way through a maze of wires. The Poynting vector gives us a powerful mathematical description of that energy flow, but the underlying physical picture remains less intuitive than the familiar image of electricity as something simply flowing through a pipe.

Nor does the conveyor-belt picture tell us what an electron ultimately is. Its charge, mass and spin can be measured with extraordinary precision, yet no internal structure has ever been detected. Whether the electron is genuinely fundamental or represents some deeper physical structure remains an open question.

See the discussion of the electron on the Æther page.

The same distinction becomes even more important in plasma. A current-carrying plasma filament is not simply the cosmic equivalent of a copper wire with electrons flowing through it. Electric and magnetic fields surround and help structure the filament, while electromagnetic energy can be transported along and around the structure as Poynting flux. In astrophysical plasmas, jets and filaments may therefore act as conduits for energy over enormous distances without requiring individual charged particles to travel from one end of the system to the other.

This offers a rather different way of viewing large-scale plasma filaments: not merely as streams of matter, but as parts of extended electromagnetic systems capable of transferring energy across space.

This is a recurring problem in electromagnetic theory. Words such as flow, current, pressure, lines and waves are enormously useful because they allow us to visualise unfamiliar processes through familiar experiences.

But the map is not the territory.

Electromagnetism remains extraordinarily successful mathematically while retaining deep conceptual mysteries about fields, charge, energy, and the physical nature of apparently empty space.