The night of 11-12 December marks 100 years since Edward Appleton’s historic experiment in Oxford, using radio waves to investigate the layers of charged particles in the Earth’s ionosphere; Department of Physics alumnus Timothy Baker shines a light on Oxford’s role in the Nobel laureate’s discovery.

Appleton had recently arrived at King’sCollege, London. With his graduate student Miles Barnett, he came to what was then the Electrical Laboratory (now the Townsend Building, it was then separate from the Clarendon Laboratory), to set up his receiver. Appleton’s host, who helped with the experiment, was Walter Gill, a specialist in radio technology. Until shortly before, Appleton had been researching thermionic valves and the effect of lightning on radio transmissionsat the Cavendish Laboratory, Cambridge.

Earlier in 1924 Appleton had set Barnett to measure the strength of radio signals received at Cambridge from the BBC’s ‘2LO’ Wireless Station in London. They found that the signal was more variable at night, with repeated ‘fading’, than in the day. Appleton thought the fading was caused by interference between a direct ground wave and a sky wave reflected from an ionised layer in the upper atmosphere that was influenced by the Sun.

Balfour Stewart had theorised in the 1860s that daily changes in the Earth’s magnetic field had a solar cause. In 1901 Guiglelmo Marconi’s transmission of radio signals from Cornwall to Newfoundland led to questions about how the radio waves could bend around the surface of the Earth. Oliver Heaviside, Edward Kennelly, and Willam Eccles explained these phenomena by theorising that there was an ionised conducting layer in the atomosphere, but no one had as yet proved its existence.

Appleton suggested doing so by receiving a pulsed signal whose frequency was regularly varied around a mean value. From the mean frequency, the frequency of the modulation, and the frequency of the beats in the received signal, the difference in the distance travelled by the ground and sky waves could be calculated, and thence, by triangulation, the altitude of the reflecting layer.

The BBC agreed to provide an experimental pulsed signal from its transmitter after it had finished broadcasting, but it could not do so from 2LO, so it offered its ‘6BM’ station at Bournemouth instead. For a clear signal, the strength of the ground and sky waves needed to be equivalent, and Cambridge was too far from Bournemouth to achieve this – hence why Appleton decided to set up his receiver at Oxford.

The experiment was arranged for after the BBC had gone off-air on 11 December 1924. The set-up complete, as they waited expectantly for the broadcast to finish, Barnett said: ‘And I always thought I liked dance music’. Eventually, just before midnight, they received a telephone call from Bournemouth to stand by, and shortly afterwards, in the small hours of 12 December, they started to obtain clear evidence of beats which pointed to an altitude of about 100km for the reflection.

There remained the possibility that the interference came from a signal reflected at ground level by hills, so in early 1925 Appleton and Barnett conducted further experiments at Oxford, using both a looped aerial and a vertical antenna, which showed that part of the signal arrived at a steep angle from the sky. And so the existence of the Kennelly-Heaviside (E) layer of charged particles in the ionosphere was proved, by refraction through and reflection from which, as the ion density and thus refractive index changes, radio waves are able to travel round the curvature of the earth.

The experiment was the first use of radio waves for distance measurement. It prompted Appleton’s further extensive exploration, at King’s College and at his experimental stations near Peterborough, in London, and at Slough, of the ionosphere and its behaviour, with far-reaching consequences for both physics and technology. He found that the E layer broke up at dawn, discovered the higher-level Appleton (F) layer of charged particles, by which radio waves are reflected during the day, and found the D layer, split off beneath the E layer later in the day, and that the F layer also splits in certain conditions.He measured the altitude of the E layer at 50 miles and the F layer at 170 miles, and variations in the ionisation of different layers of the atmosphere through the day. On the basis of regular reports from a worldwide network of ionospheric observatories, he identified magnetically induced variations in the heights of the ionised layers,and the electric currents induced by the tidal movement of their particles through the Earth’s magnetic field. For this work, which assisted the determination of the best wavelengths for radio transmission, Appleton won the Nobel Prize for Physics in 1947.

Appleton suggested in 1924 that high frequency, short wavelength radio waves should be less subject to absorption and attenuation than long waves,and he went on to use these waves to probe the ionisation of the atmosphere, and identify the point at which it becomes transparent to radio waves:the ‘window’ that is used for radio astronomy. Appleton also perfected the pulse technique that Robert Watson-Watt used, with higher power and shorter pulses, for radar.

Radar in turn was destined to become the driving force for the emergence of the Clarendon Laboratory, by now a physics powerhouse, as a leader of microwave research during and after the Second World War. Walter Gill had already, in 1922, along with Clarendon Laboratory demonstrator and Oxford brewer James Morrell, researched the relationship between oscillating frequency and electrode characteristics: one of the foundations of the development of magnetrons as microwave generators.

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LINK:  https://nevillewright.com/wp-content/uploads/2025/01/Operation-Fishbowl.mp4?_=1  

In the early 1960s,a highly classified operation called Operation Dominic was launched, marking a bold attempt to test humanity’s boundaries in the quest for space exploration and nuclear capabilities. However, what seemed like a routine series of missile tests quickly spiraled into something much more mysterious. These tests, which involved shooting 31 missiles straight into the sky,weren’t just a simple scientific experiment—they raised questions about the very nature of our atmosphere and the limits of human reach.

The Unexpected Discovery: A Barrier in the Sky

As the missiles shot up, the results were not as expected.Rather than effortlessly cutting through the sky, the missiles began to explode in mid-air.At first, these explosions appeared to be the result of typical technical malfunctions,but further analysis suggested something far stranger was at play. The missiles seemed to be interacting with something other than just the air—a field of electromagnetic phenomena,or as some theorists suggest, a kind of “plasma field.”

This field appears to have fluid-like properties, responding to the missiles as they passed through different layers of electromagnetic forces. As the missiles ascended, they encountered what seemed like a kind of invisible barrier. Upon hitting this force field, the missiles didn’t just explode randomly. They dispersed and sought equilibrium, interacting with the varying electromagnetic layers as if hitting an impassable wall. It was almost as though the missiles were not just being stopped by air resistance but by an unseen, impenetrable force.

The Firmament Theory: A Barrier to Escape

This anomaly leads to an intriguing theorythat has gained traction in certain circles: the idea of a firmament. The concept of a firmament, a solid barrier above the Earth, (Just as the Bible Says) has been around for centuries, but it gained renewed attention after these missile tests. Some believe that the missiles were not just hitting a force field or electromagnetic layers—they were attempting to breach the firmament, a layer separating our world from whatever exists beyond.

The theory posits that no matter how advanced our technology becomes, this firmament—whether a literal or metaphysical boundary—cannot be crossed. It’s a limit, a wall of sorts that we cannot seem to penetrate.In this view, the firmament represents more than just an atmospheric layer; it’s a boundary, a metaphorical and physical ceiling to human ambition.The firmament doesn’t just stand as a physical barrier; it also implies that there are boundaries to human understanding and technological advancement,a concept that many believe is being revealed through these tests.

The Implications: Testing the Limits of Human Knowledge

Why were these tests conducted? On the surface, Operation Dominic was an effort to test missile technology and the effects of nuclear explosions in space. However, if we consider the possibility that these missiles were hitting a barrier, it could mean that the operation was not merely about testing nuclear weapons but about exploring the boundaries of the Earth’s atmosphere—or beyond. Perhaps these tests were the beginning of humanity’s efforts to understand the very limits of our physical world.

This idea challenges many of the assumptions we have about space, the sky, and the nature of the universe. It suggests that, despite all of our technological advancements, there may be limits to how far we can push beyond the Earth’s atmosphere. The explosions captured on footage seem to suggest a struggle against a force that no technology, no matter how advanced, can yet conquer.

What’s Going On? A Cosmic Puzzle

The real question is: What’s going on? Could it be that we are truly bound by a firmament above?Is it possible that no matter how high we go, we are inherently limited by some natural force or cosmic law? Or is the phenomenon the result of something we still don’t fully understand—something about the electromagnetic layers or plasma fields that we have yet to properly study and define?

One thing is certain: the events of Operation Dominic are far from being just another forgotten chapter in the history of missile testing. They raise deep questions about the nature of our existence and the physical laws that govern our world.And whether or not you subscribe to the theory of a firmament, the very fact that these tests revealed such unusual results suggests that there is still so much about our universe that we have yet to comprehend.

So, the next time you look up at the sky, consider this: Are we truly free to reach beyond, or are there limits—both physical and metaphysical—that we have yet to understand? The journey to answer that question may just be the key to understanding our place in the cosmos.

The timeframe for Operation Dominic and Operation Fish Bowl is as follows:

• Operation Dominic: Planning began in October 1961,with the first test planned for October 1961,but the first  test was delayed until June 1962.The tests were conducted from April to November 1962. 

• Operation Fish Bowl: The first test attempt was delayed until June 1962,and the tests were conducted from June to December 1962. 

  These operations were part of the larger Operation Dominic program, which included numerous atmospheric nuclear tests conducted by the United States.The tests were aimed at evaluating the destructive mechanisms and effects of high yield explosions against ballistic missile ranges and to gather further weapons effects data on high-altitude phenomena. 

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The Firmament? Operation Fishbowl- The Day They Tried to Bomb Heaven

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Jodrell Bank Observatory celebrates 70 years of radio astronomy

Published

14 December 2015

The 70th anniversary of an astronomer’s first steps into a “whole new science” at one of Britain’s most important stargazing sites has been marked.

Sir Bernard Lovell began using radio astronomy in 1945 at the opening of the fledgling Jodrell Bank Observatory.

The Cheshire site would later become home to the iconic radio telescope which bears the astrophysicist’s name.

Its director Prof Tim O’Brien said his work had given astronomers the chance to look at “the invisible universe”.

The anniversary has been marked with the launch of a year-long programme of events celebrating “the past, present and future of Jodrell Bank’s science, engineering and heritage”, a spokeswoman said.

In April, the site was chosen as the worldwide headquarters for the Square Kilometre Array project, which will probe the early universe, test the theory of gravity and even search for alien life.

Prof O’Brien said that achievement was a direct result of Sir Bernard’s work, as he pioneered a “whole new science[through which] we discovered a whole new universe out there,full of super massive black holes, exploding stars and the fading glow of the Big Bang”.

Image source,University of Manchester

Image source, Mike Peel/University of Manchester

Sir Bernard, who died in 2012,set up old Army radar equipment on the site to detect cosmic-rays and investigate meteors and began work on 14 December 1945.

The huge Lovell Telescope was completed in 1957and, during its first year, it was the only facility in the West able to track the rocket carrying the Russians’ first satellite, the Sputnik, into space.

It went on to confirm the existence of pulsars –dying stars that send out pulses of electromagnetic radiation – in 1968 and, in 1979, was instrumental in proving Einstein’s theory of relativity for the first time.  (Never been proven, still a theory, and many scientists believe it has been proven wrong.)

In 2006, it was named as Britain’s greatest unsung landmark, external in a BBC poll.

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