The history of modern physics is often told principally through gravity, relativity and quantum mechanics. Yet running alongside it is another, remarkably persistent thread — one concerned with electricity, magnetism, fields, currents and plasma.

From Faraday's lines of force and Maxwell's electromagnetic field, through Heaviside, Steinmetz and Tesla, to Birkeland, Langmuir, Alfvén and Peratt, successive generations explored electromagnetic phenomena and their implications for our understanding of nature.

The path was rarely straightforward. Ideas that appear obvious in hindsight were often resisted when first proposed because they challenged the accepted physical picture. Faraday's lines of force replaced action at a distance with something more physically immediate: a field extending through space. Maxwell then transformed that insight into a mathematical theory in which electricity, magnetism and light became manifestations of the same underlying phenomenon.

Such episodes illustrate a recurring feature of scientific change. As Thomas Kuhn would later argue, established paradigms do more than organise existing knowledge; they also influence which questions are considered important, which explanations appear reasonable, and sometimes which possibilities are taken seriously at all. A new idea may therefore struggle not simply because the evidence is weak, but because it does not fit comfortably within the prevailing conceptual framework.

Electromagnetism itself provides a striking example. Concepts once regarded as speculative or difficult to accept became foundations of modern physics. The lesson is not that unconventional ideas are necessarily correct, but that consensus at any particular moment should never be confused with the final word.

The figures below did not form a single school, nor did they necessarily share the same theories. What connects them is something broader: the recognition that electricity and magnetism are fundamental physical phenomena whose consequences extend far beyond the laboratory.

Faraday → Maxwell → Heaviside → Steinmetz → Tesla →
Birkeland → Langmuir → Alfvén → Peratt

"The phenomena of electrical discharge are exceedingly important, and when they are better understood they will probably throw great light on the nature of electricity as well as on the nature of gases and of the medium pervading space."
James Clerk Maxwell,
Treatise on Electricity and Magnetism.

While we now recognise electricity and magnetism as inseparable aspects of electromagnetism, this relationship only became clear during the nineteenth century.

Michael Faraday transformed the subject experimentally. His work on electromagnetic induction showed that a changing magnetic environment could generate an electric current, while his concept of lines of force encouraged a radically different way of thinking about physical interaction. Forces need not simply act mysteriously across empty space; the field itself could be physically significant.

James Clerk Maxwell subsequently placed Faraday's insight into a unified mathematical framework. Electricity, magnetism and light emerged as different aspects of the same electromagnetic phenomenon.

Maxwell's achievement was more than mathematical elegance. His theory described electromagnetic energy as something capable of existing and propagating through space. For Maxwell and many of his contemporaries, the field was not merely an abstract calculation but represented a physical process occurring in an underlying medium.

Oliver Heaviside is remembered today largely for reformulating Maxwell's cumbersome original equations into the compact vector form familiar to physicists and engineers. Yet his interests extended considerably further.

In 1893, more than two decades before Einstein's General Theory of Relativity, Heaviside published A Gravitational and Electromagnetic Analogy. Dissatisfied with the idea of gravity acting instantaneously across empty space, he asked whether gravity might possess a field structure analogous to electromagnetism.

The comparison was striking. Just as electric charge produces an electric field, mass produces a gravitational field. And just as moving electric charge produces magnetic effects, Heaviside proposed that moving matter should produce an additional gravitational effect analogous to magnetism.

"Now what is there analogous to magnetic force in the gravitational case? And if it have its analogue, what is there to correspond with electric current?"
Oliver Heaviside, 1893

Heaviside constructed gravitational equations closely resembling Maxwell's electromagnetic equations, including a field associated with the motion — or "flux" — of matter. He also explored the possibility that gravitational disturbances propagated at a finite velocity rather than acting instantaneously across space.

He did not demonstrate that gravity was electromagnetic, nor did his formulation require it to be. The source of his gravitational field remained mass rather than electric charge. What he demonstrated was that Maxwellian field concepts could be extended remarkably far into gravitational physics.

What makes the episode particularly interesting in hindsight is that modern physics does recognise an analogous phenomenon. Today it is known as gravitomagnetism, appearing in the weak-field, slow-motion limit of General Relativity.

Heaviside had reached remarkably similar mathematical territory in 1893.

Perhaps equally significant was the physical picture underlying his reasoning. Following Maxwell, Heaviside did not regard space as simply empty. He considered an underlying medium capable of carrying energy and transmitting physical effects.

"Now what is there analogous to magnetic force in the gravitational case?"
Oliver Heaviside

Another important link in the electromagnetic tradition was Charles Proteus Steinmetz, one of the great electrical engineers of the late nineteenth and early twentieth centuries.

Steinmetz helped turn the rapidly developing science of alternating current into a practical engineering discipline. His work on magnetic hysteresis explained energy losses in electrical machinery, while his use of complex mathematics greatly simplified the analysis of alternating-current circuits.

He was also deeply interested in electrical transients — sudden, short-lived surges of voltage and current produced when an electrical system changes state. Lightning, switching events, oscillations and high-voltage discharges all belonged to a world in which electricity behaved dynamically rather than as a simple static force.

This distinction is important. Electricity in nature is rarely confined to stationary charges. Real electrical systems involve moving charge, changing fields, oscillations, currents and feedback between electric and magnetic effects.

Steinmetz therefore occupies an interesting position between Maxwell's theoretical unification and the extraordinary high-frequency experiments of Nikola Tesla. He helped establish the mathematical and engineering language through which complex electrical behaviour could be analysed in the real world.

Nikola Tesla pushed electrical experimentation into still more unusual territory. Working with extremely high voltages and high-frequency alternating currents, he produced spectacular electrical discharges, explored resonance and wireless transmission, and repeatedly questioned conventional assumptions about how electrical energy propagated through space.

Tesla's ideas were often unconventional and not all of them were demonstrated successfully. Yet his experimental work emphasised something that would become increasingly important in plasma physics: under sufficiently strong electrical stress, gases cease to behave as ordinary neutral gases and become electrically active, luminous and structured.

Tesla's laboratory was therefore exploring phenomena that today would be recognised as electrical discharge and plasma behaviour decades before plasma became a distinct scientific discipline.

His work also retained the older Maxwellian conviction that space itself could possess physical properties capable of transmitting energy. Tesla never accepted the idea that apparently empty space was literally nothing.

For a fuller discussion of Tesla's work, see the Nikola Tesla page.

Seen in isolation, Birkeland's electrical universe, Alfvén's cosmic plasma and Peratt's later plasma simulations can appear to be departures from the mainstream history of physics. Seen against the longer history of electromagnetic research, they look rather different.

They belong to a continuing tradition stretching back through Tesla, Steinmetz and Heaviside to Maxwell and Faraday — a tradition in which fields, currents and electrical processes were regarded not merely as laboratory curiosities, but as fundamental features of the physical world.

The next decisive step was to take those ideas beyond the laboratory.

Kristian Birkeland proposed electric currents connecting the Earth with space. Irving Langmuir gave ionised matter its modern name — plasma — and explored its complex laboratory behaviour. Hannes Alfvén then carried plasma physics into astrophysics and cosmology, arguing that laboratory plasma behaviour could not simply be ignored when interpreting the heavens.

Those three figures form the central plasma lineage described in History I. Anthony Peratt would later extend that tradition still further, using particle-in-cell computer simulations to investigate the behaviour of enormous current-carrying plasma structures on galactic scales.

Plasma is not merely an ionised gas. It carries electric currents, generates magnetic fields, forms double layers, and naturally organises itself into cellular, filamentary, and spiral structures. If the visible universe is overwhelmingly plasma, why does gravity continue to dominate almost every cosmological explanation?

The answer is not that astronomers deny plasma. Quite the opposite. Modern astrophysics routinely studies plasmas, magnetic fields, and charged particles. The real question is why electrodynamics so often plays a supporting role, while gravity remains the principal actor. The answer lies partly in history, partly in mathematics, and partly in the way scientific paradigms evolve.

A Historical Detour

Kepler and Newton could hardly have incorporated plasma physics into their models. Their achievements were extraordinary, but they were necessarily products of their time. The foundations they laid were gravitational because the electron, electromagnetic field, plasma and even the electrical nature of matter itself had yet to be understood.

By the beginning of the twentieth century that situation had changed dramatically. Electricity and magnetism had become unified, the electron had been discovered, electrical engineering was transforming society, and laboratory experiments were revealing increasingly complex behaviour in ionised gases.

For a time it seemed entirely reasonable to ask whether electrical processes might also operate on astronomical scales. Birkeland's auroral research and terrella experiments pointed directly in that direction.

Yet twentieth-century cosmology ultimately followed another path. Relativity revolutionised gravity and quantum mechanics transformed atomic physics. Plasma physics flourished in laboratories, engineering and eventually space science, while cosmology became increasingly gravitational in emphasis.

Electricity never disappeared from astronomy. It simply ceased to occupy centre stage.

The Map and the Territory

A good equation is a map. It may be astonishingly accurate. It may guide spacecraft, predict eclipses, and describe patterns with extraordinary precision. But a map is not the territory. When a model repeatedly requires invisible substances, unobserved energies, or idealised assumptions to preserve itself, we should ask whether nature is becoming more complicated — or whether the model is being protected from revision.

Electrodynamics versus Fluid Dynamics

Another common habit is to describe electrodynamic phenomena in terms more appropriate to fluid dynamics. "Electron rains", "ion storms", "solar wind", and "magnetic ropes" are familiar examples. These phrases are convenient, but convenience can come at a cost. They may obscure the current systems and electromagnetic forces that organise plasma at every scale.

So-called magnetic ropes are more properly understood as current-carrying plasma structures — Birkeland currents. They are not merely shapes in a magnetic field. They are electrical structures sustained by moving charge.

Bad Astronomy versus Good Science

Phil Plait, the self-proclaimed Bad Astronomer, has long been a critic of the Electric Universe. In 2007, on his website badastronomy.com, he argued that astronomy does not ignore magnetic fields. But this misses the central point. The issue is not whether astronomy mentions magnetic fields. The issue is whether it properly acknowledges the electrical currents that generate and sustain them.

"Magnetism is a very important topic in astrophysics (despite some pseudo-scientists lying and saying this force is ignored), but it’s not well-understood. It’s fiendishly complex, so much so that it’s a joke in astronomy."
Phil Plait, The Bad Astronomer

The admission is revealing. Magnetism is acknowledged, but not fully understood. The missing piece is often the electrical current. Magnetic fields do not arise in isolation. They are produced by moving charge.

"In order to understand the phenomena in a certain plasma region, it is necessary to map not only the magnetic but also the electric field and the electric currents."
Hannes Alfvén, Nobel Laureate

In other words, magnetism cannot be viewed in isolation. To map only the magnetic field while neglecting the electric field and current system is to describe the shadow while ignoring the object casting it.

Plasma cosmology does not ask us to abandon gravity. It asks us to restore electricity to the role it has occupied since Maxwell unified electromagnetism. The universe appears not merely gravitational, but electrical. Recognising that possibility is not the abandonment of science. It is an invitation to follow the evidence wherever it leads.

"Newton was unaware of plasma. Today his disciples spend years in training learning when and how to shut their eyes to it."
Mel Acheson

"Never attribute to malice that which can be adequately explained by stupidity, but don't rule out malice."
Heinlein's Razor

"Facts do not cease to exist because they are ignored."
Aldous Huxley

The history of plasma physics reveals a recurring tension between mathematical elegance and experimental complexity. Real plasmas display currents, filaments, double layers, instabilities, oscillations and sharply differing particle temperatures — behaviour that does not always lend itself to simple mathematical treatment. This helps explain why plasma physics has often occupied a secondary role in mainstream cosmology, despite plasma constituting more than 99 per cent of the visible universe.

Australian physicist Wal Thornhill drew attention to this historical divide between the experimental study of electrical discharges and the more mathematically attractive attempt to extend the kinetic theory of ordinary gases to ionised matter:

"Plasma physics started along two parallel lines. One of them was the hundred-year-old investigation into what was called 'electric discharges in gases'. To a high degree, this approach was experimental and phenomenological, and only very slowly did it reach some degree of theoretical sophistication. Most theoretical physicists looked down on this field which was complicated and awkward. The plasma exhibited striations, double layers, and an assortment of oscillations and instabilities. The electron temperature was often found to be one or two orders of magnitude larger than the gas temperature, with the ion temperature intermediate.

"In short, it was a field which was not well suited for mathematically elegant theories. The other approach came from the highly developed kinetic theory of ordinary gases. It was thought that, with a limited amount of work, this field could be extended to include ionized gases. The theories were mathematically elegant and claimed to derive all of the properties of a plasma from first principles. In reality this was not true. Because of the complexity of the problem, a number of approximations were necessary which were not always appropriate. The theories had very little contact with experimental physics: all awkward and complicated phenomena observed in the laboratory were simply neglected... Theories about plasmas, at the time called ionized gases, were developed without any contact with laboratory plasma work. In spite of this — or perhaps because of this — belief in the theories was so strong that they were applied directly to space. One of the results was the Chapman-Ferraro theory (for a review see Akasofu and Chapman, 1972) which became accepted to such an extent that Birkeland's approach was almost completely forgotten. For thirty or forty years, Birkeland's results were often ignored in textbooks and surveys, and all attempts to revive and develop them were neglected.

"The crushing victory of the theoretical approach over the experimental approach lasted only until the theory was to make experimentally verifiable predictions. From the theory, it was concluded that in the laboratory, plasmas could easily be confined in magnetic fields and heated to such temperatures as to make thermonuclear release of energy possible. When attempts were made to construct thermonuclear reactors, a confrontation between the theories and reality was unavoidable — the results were catastrophic. Although the theories were generally accepted, the plasma itself refused to believe them. This is not to say that Juergens' theory that the sun is an anode is valid. His observation was that the sun appears to violate the 2nd law of thermodynamics in that the heat transfer is the wrong way. My friend Leroy, if I recall correctly, once attempted to explain this by an analogy of a man with a cigarette lighter in his extended arm. Neither suggestion is correct as the sun is not a collection of ordinary gas. It is a collection of matter in the plasma form and, as such, the temperature of the electrons is orders of magnitude higher than the rest of the body (a normal condition for a plasma).

"The approach which Alfvén suggested must ignore the elegant and simplistic ordinary gases theory as the electromagnetic forces within a plasma dominate."

The significance of this history extends beyond plasma physics. Mathematical models are indispensable, but a model necessarily simplifies the physical system it describes. When those simplifications become embedded in an established theoretical framework, there is a danger that inconvenient observations are treated as complications to be averaged away rather than clues to missing physics.

Alfvén repeatedly warned against precisely this tendency. His approach was grounded in laboratory plasma behaviour: begin with what plasma actually does, then ask whether the same processes can operate on larger scales. The distinction is subtle but important. Instead of forcing plasma to behave like an idealised gas, the laboratory evidence is allowed to determine which approximations are physically justified.

The history also provides another example of the scientific inertia discussed earlier. Birkeland's electrical interpretation of the aurora was marginalised for decades, only for spacecraft measurements eventually to confirm the existence of the field-aligned currents he had proposed. The lesson is not that mathematics is the problem. It is that mathematical elegance can never substitute for physical evidence.

And as astronomy opened new observational windows onto the universe, evidence for the importance of charged particles and electromagnetic processes became increasingly difficult to overlook.

The nineteenth-century development of electromagnetism was closely connected with the idea of an underlying medium. Faraday's fields, Maxwell's electromagnetic waves, and the later work of Heaviside, Lodge and others were developed in a physical picture in which apparently empty space possessed structure and could transmit energy.

The æther was eventually displaced from mainstream physics following the rise of Special Relativity, although the historical story is considerably less straightforward than is sometimes suggested. Researchers including Dayton Miller continued to report positive æther-drift results, while Einstein himself acknowledged that confirmation of such results would require fundamental revision of relativity.

Questions surrounding the æther, Michelson-Morley, Miller, Einstein, electromagnetic waves, the quantum vacuum and the physical nature of space are explored in greater detail on the dedicated æther page.

One issue remained particularly relevant to the relationship between electromagnetism and gravity. In 1998, physicist Tom Van Flandern published a paper in Physics Letters A arguing that Lorentz's interpretation of relativity — which retained an underlying preferred frame — was physically preferable to Einstein's formulation. Van Flandern also argued that gravitational influence propagates far faster than light, closer to the effectively instantaneous behaviour assumed in Newtonian celestial mechanics.

Whatever one makes of that conclusion, the broader question remains significant. If gravity, electromagnetism and the properties of space are ultimately related, then the nineteenth-century search for a physical medium may not have been quite the intellectual dead end it is often portrayed as being.