Project Greenglow: How Horizon Lost The Message In The Medium

John Eades


Several years ago, I acquired a recording of Sibelius’s fifth symphony. This is one of his best-known works, but the version I received was the original 1915 one rather than the revised 1919 version, which until fairly recently was the only recording ever heard. What I expected were minor changes in orchestration, with perhaps a few passages removed or extended here and there. What I got was the kind of shock you might feel if you met someone in the street you had known all your life and found that he was twenty centimeters taller than he was three weeks last Tuesday and that his hair had turned blue. When I cast a skeptical eye over newspaper, magazine, and television coverage of scientific topics, I often get much the same feeling.1

The medium is the message, a phrase coined in the 1960s by the Canadian philosopher Marshall McLuhan, became what was perhaps the most successful, and least understood, meme of the age. Arguments still rage about what McLuhan really meant, but it seems to me that he may at least have gotten it right about science reporting: the media decide what the message of science is, not the scientists. The requirement that TV science presentations keep the viewer entertained and tuned in means that they can easily wind up as a PR pitch for some supposed future technological miracle, while reality and the true nature of the science involved are largely ignored or obscured.

Making Apples Fall Up

The March 23, 2016, episode in the BBC’s science series Horizon, titledProject Greenglow,” was billed as “the story of an extraordinary scientific adventure—the attempt to control gravity” (Horizon 2016). The episode provides us with a textbook case of real science disappearing in medium-promoted PR.2

In the real world gravity controls us, not the other way around, and scientists talk about measuring or understanding natural forces, not about controlling them. It quickly became clear that “controlling gravity” meant getting it to push things (such as Newtonian apples!) up instead of pulling them down. Extraordinary? What was extraordinary to me was that almost the entire program was devoted to things being pushed upward by forces other than gravity, such as electromagnetism, or to gravitational contraptions that were supposed to push up but didn’t. And the green glow was more like a red light warning the viewer to treat most of what followed with extreme skepticism.

  “Project Greenglow” was, it seems, a 1990s scheme by U.K. defense contractor BAE Systems, which apparently “set about turning science fiction into reality. The episode’s main protagonist was a BAE aerospace engineer named Ron Evans, but neither he nor BAE were alone in this effort. Across the pond, NASA had its own idea about things that glow green, but they called it the Breakthrough Propulsion Physics Project. It involved such things as space applications of “new physics,” “faster-than-light travel,” and “warp drives.” “What new physics?” I wondered, and why hadn’t I heard of it? Has it, as Horizon claimed, “helped change our understanding of the Universe?” And did all this really make “the dream of flying cars and journeys to the stars no longer seem quite so distant?”

Gyroscopes and Gravity

Horizon traced its theme back to a 1990s demonstration at the Royal Society, London, in which gyroscopes appeared to be producing a repulsive gravitational field. The late Professor Eric Laithwaite, who originally promoted this as a real effect, to his credit subsequently admitted that this phenomenon was illusory.

  CERN theorist Professor John Ellis explained why: The forces of nature are well understood in terms of quantum field theory, which, in the electromagnetic case, permits two kinds of electric charge, positive and negative. Just as like electrical charges repel, unlike ones attract. For gravity, the property analogous to electric charge is mass. This is always positive, but in gravitational fields the “likes repel” rule does not hold, and every mass attracts every other. The gravitational pull of all the atoms in the Earth therefore add up to produce what we call weight or the force of gravity.3

Killjoy Academics

Logic would dictate that the entire program end at this point. This would have ruined a good story, so it continued for another forty-five minutes with a number of nonarguments and descriptions of nonworking gadgetry suggesting that some really serious science was forthcoming. Saying things such as: “Academics jump on any antigravity device as being—impossible! Well it’s not impossible it’s just that we don’t how to do it,” is not, however, a scientific argument. Neither is the statement: “It’s like flight in the nineteenth century—in those days anybody who said they could fly was looked upon as a lunatic.” And Evans’s admission that the green rays he added under a drawing of a VTOL aircraft were only put in to make the idea of a working nuts and bolts antigravity machine look plausible did nothing to encourage the critically minded viewer to take what was to follow seriously.

Levitation Experiment Falls Flat

In the late 1990s, Russian chemist Yevgeny Podkletnov claimed to have observed gravitational levitation of a small test object placed over a spinning superconducting disk (his first inkling of this came—and I am not making this up—when he saw the disc levitating tobacco smoke from a colleague’s pipe!). Even if it had been genuine, the claimed effect was tiny, but Podkletnov nevertheless insisted that his device could destroy missiles—remove them from their trajectory. After both BAE and NASA had tried unsuccessfully to replicate his results, they gave up. Podkletnov, by then fearful of prying military eyes and ears, arranged a secret meeting with Dr. Evans in a London hotel, in which he described an improved version of his device. This, he claimed, delivered a gravitational push that was detectable a kilometer away. Evans admitted that he could draw no conclusion from the meeting but nevertheless solemnly remarked, We don’t know with gravity. Gravity is a subject we don’t know about! That’s why we are exploring it .” Experiments at the Technical University of Dresden with a replica of the new device nevertheless failed to show any evidence that gravitational pulses were being propagated, even over short distances within the laboratory.

Nongravitational Apple-Pushers

Much of the program described various devices that did indeed push objects upward, or purported to, but not by gravity. This incongruence apparently troubled neither the producer nor many of the participants. Thus an electromagnetically levitated magnetic disc was shown with the comment, “Wouldn’t it be great if we could get gravity to work in reverse and be able to levitate things with gravity?”, while Roger Shawyer’s EMDrive (Shawyer 2006), which claims to generate a propulsive thrust without an equal and opposite reaction, was discussed at great length. NASA, which would like to send space probes to the stars without the inconvenience of carrying trillions of tons of propellant, displayed a close interest in this microwave oven–like device, but in the face of unconvincing results soon defunded research on all novel propulsion systems.Who cares?said Evans. “If it works it’s up to the theorists to find out why.” Unfortunately, it doesn’t. Further work by the Dresden team that investigated Podkletnov’s device (Tajmar and Fiedler 2015; Koepsell 2015; Tramiel 2015), also found that any thrust produced by the EMDrive was within the experimental margin of error.

Shawyer has now produced a new, improved, bigger EMDrive that, he says, does work. Of course he has never claimed to make apples or anything else fall upward under gravity, only to violate Newton’s third law!

Cosmic Repulsion?

In response to the fact that Podkletnov’s kitchen sink–sized gadget should have generated a gravitational push and didn’t, Horizon simply changed course and talked up the idea that levitation of earthly objects might be achievable by tapping into cosmic energies.

There is in fact a tenuous connection here with the observed acceleration of the expansion of the universe, which is suspected to be caused by a so-called dark energy that fills space and pushes the universe outward. True to form, Horizon highlighted only the most speculative and questionable explanations of this phenomenon. One of these is the concept of negative mass, which at first sight would fit Greenglow’s bill nicely since negative masses would move in the opposite direction to the pull of gravity. Quite how this idea, even if it were correct, might manifest itself in an earthly setting, where no negative mass object has ever been seen, was a can of worms that Horizon chose not to open. Moreover, as University of Southern California physicist Professor Clifford Johnson explained, such notions have huge problems with runaway instabilities, which should be easily detectable but have never been observed anywhere in the universe.

Einstein initially included in the theory of general relativity a form of dark energy—the cosmological constantto hold back gravity and keep the universe static. When Hubble later found that the universe was not static but rather expanding, he removed it. Putting it back in is now generally accepted as the best explanation for dark energy rather than introducing highly problematic negative masses.

Hands-On Dark Energy

Loath to abandon the imagined promise of dark energy, Horizon moved on to dream about stockpiling it. One participant suggested that dark energy has some form of antigravity—we still don’t know whether we can ever harness it” while the background commentary suggested that the idea that the universe has some inherent form of antigravity is tantalizing—if only we could get our hands on it.”

  Well let’s suppose that we could: The density of dark energy has been estimated to be about 0.63 joules per cubic kilometer. A simple calculation shows that the amount contained in a volume the size of the Earth (1012 cubic kilometers) would raise a 2,000-ton vessel, the approximate lift-off weight of a space shuttle, about 330 km into the air—not exactly encouraging news for any idea NASA might have for dark-energy–powered star probes. “Just hilariouswas Prof. Johnson’s understandable reaction to these ideas.

Upward Falling Antimatter and Wobbling Atomic Clouds

In its continued quest to ransack the universe from top to bottom for evidence of repulsive gravitational forces, Horizon then lurched from the cosmic to the atomic scale, misrepresenting certain ongoing experiments on hydrogen and antihydrogen atoms at CERN. These aim to test for any small difference in the free-fall of these matter–antimatter pairs under gravity. This would violate the Equivalence Principle, the modern synthesis of Galileo’s findings at the tower of Pisa. There being good grounds to expect that the principle applies on the atomic as well as the bulk matter scale, the experimenters do not expect to find that antihydrogen falls upward. Even if they did, it would take many thousands of times the age of the universe to collect the 2,000 tons or so of antihydrogen atoms necessary to push a space shuttle–sized payload skyward. And of course, apart from the problem of confining such a gigantic number in a small space, they would annihilate the very payload they were supposed to push.

The final topic concerned a quantum gravity gradiometer, a device that detects small changes in the local gravitational field by their effect on a cloud of ultra-cold atoms. A slight wobble of the cloud as an experimenter moved around was interpreted to mean that the gradiometer was sensitive to the gravitational field of a human being–sized object.4 No justification was presented for this (nor the further claim that the laws of nature as we know them were somehow being broken). Ever the optimist, Dr. Evans saw the wobble as a start on the road to controlling gravity in the future and summed up the entire Horizon episode with the words: “Gravity control is just something we haven’t learned to do—yet …. I’m sure we will one day; it’s just a matter of time.”

A Flagship Science Series?

The message delivered by the medium of television in this episode of Horizon was not a scientific one. Rather it was that one of the world’s most respected media organizations gussied up a collection of smoke-and-mirror arguments as real science under the rubric of what it claims to be its gold-standard science series. The lone voices of mainstream science, Professors Ellis and Johnson, were heard for a total of about three to four minutes during the sixty-minute episode. Given the speculative and handwaving arguments of the accompanying commentary, I was not really surprised to find that it was narrated by an actor from the BBC science-fiction series Doctor Who. Nor was I sure that all the participants realized the extent to which their remarks would be decontextualized and trivialized in the actual broadcast.

  This is not the first time that Horizon has failed to live up to its advertised role as a serious and reliable vehicle for presenting scientific topics to nonscientists (Close 2007). Richard P. Feynman once remarked that for a successful technology, reality must take precedence over public relations, for you cannot fool nature. These wise words seem to have vanished over this particular Horizon.


  1. A similarly titled article with the same theme but a quite different body of material appeared in The Pantaneto Forum (April 2006), available online at
  2. On account of the gadfly nature of this Horizon episode, with contextless soundbites being freely inserted at will and incomplete or nonexistent connecting material between the various topics covered, this article could not always stick to the program’s chronological sequence.
  3. The latest success of field theory in its application to gravitation was spectacularly achieved just weeks before the Horizon broadcast, when the gravitational waves the theory predicts were detected after decades of searching. This great achievement in real science did not even get a mention in the “Project Greenglow” episode.
  4. Gravity gradiometers are quite common devices, with uses in geophysics and geology. The claim about the wobble may be true, but in the absence of any supporting information there was no way of checking it.


  • Close, F. 2007. Fears over factoids. Physics World 20(8): 16–17.
  • Horizon. 2016. Project Greenglow. BBC2 (March 23). Producer’s article available online at
  • Koepsell, D. 2015. From N-rays to EMDrives: When does science become pseudoscience? Skeptical Inquirer 39(6): 14–15.
  • Shawyer, R. 2006. SPR Ltd. Internal document. Available online at
  • Tajmar, M., and D. Fiedler. 2015. Direct thrust measurements of an EMDrive and evaluation of possible side-effects. Available online at
  • Tramiel, L. 2015. Is the EMDrive pseudoscience? Skeptical Inquirer 39(6): 16–17.

John Eades

John Fleck is a science journalist for the Albuquerque Journal. His book The Tree Ring Tales: Understanding our Changing Climate will be published by the University of New Mexico Press in the fall of 2009. His website is available at

Introduction Several years ago, I acquired a recording of Sibelius’s fifth symphony. This is one of his best-known works, but the version I received was the original 1915 one rather than the revised 1919 version, which until fairly recently was the only recording ever heard. What I expected were minor changes in orchestration, with perhaps …

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