Centauri Dreams

“A man hears what he wants to hear and disregards the rest.”

So sang Simon & Garfunkel in their 1968 ballad “The Boxer.” Human nature seems to drive us to look for what we most want to happen. It’s a tendency, though, that people who write about science have to avoid because it can lead to seriously mistaken conclusions. In science itself there is a robust system of peer review to evaluate ideas. It’s not perfect but it’s a serious attempt to filter out our preconceptions. As with the flap about ‘faster than light’ neutrinos at CERN, we want as many qualified eyes as possible on the problem.

Journalists come in all stripes, but of late there has been a disheartening tendency to prove Paul Simon’s axiom. Not long ago we went through a spate of news stories to the effect that NASA was investigating warp drive. True enough — the Eagleworks team at Johnson Space Center, under the direction of Harold “Sonny” White, has been looking at warp drive possibilities for some time, though it could hardly be said to be a well-funded priority of the space agency. The budget for the Eagleworks effort has been small, and Eagleworks is only a small part of Dr. White’s job description, which focuses mostly on his acknowledged expertise in ion thrusters and related technologies.

But many of the recent stories went well beyond the facts, implying that warp drive is a major project at NASA. Numerous sites featured images of what the purported ship would look like, and the implication was that NASA had already produced designs for the vessel, meaning that breakthroughs that would allow faster than light propulsion were in the works. Anyone involved with the breakthrough propulsion community can tell you that this is not the case despite the exultant nature of some of the Internet postings. Dr. White himself has always criticized media hype and has done everything he can to distance himself from it.

Science proceeds through careful experimentation and theorizing. We also need to see well-developed analysis of any experimental apparatus that is producing anomalous results, to see if we can verify what’s going on. If the apparatus has a flaw, those operating it may not realize that effects apparently being generated by their theory are actually artifacts of the equipment being used. Such a result may be developing with regard to the White/Juday Interferometer, the key tool involved in the JSC studies of warp drive physics.

It’s not making any headlines, but a new study from Jeff Lee and Gerald Cleaver (both affiliated with the Early Universe Cosmology & Strings Group, Baylor University) has appeared, bearing a title that makes the paper’s case: “The Inability of the White-Juday Warp Field Interferometer to Spectrally Resolve Spacetime Distortions.” You can find it here. The tool in question is the one being used at Eagleworks to study possible space-time distortions of the sort that might lead one day to a warp drive. About it, the paper has this to say:

The White-Juday Warp Field Interferometer has been demonstrated to be incapable of resolving the minute distortions of spacetime created by both 10⁶ V·m^-1 electric fields and a 1 kg mass.

And this:

Variations in temperature were shown to produce potentially detectable changes in the refractive index of air, which could result in occasional spurious interference fringes. Although a more rigorous model, which considers a time-changing index of refraction gradient along the interferometer arm, would result in a smaller lateral beam deviation, the purpose for which the WJWFI is intended has been shown to be unachievable.

And this:

…were any signals to appear in the White-Juday Warp Field Interferometer, they would most often be attributable to either electronic noise or the classical electrodynamics interaction between the ionized air between the plates and the electromagnetic radiation of the laser.

Note that last point: Noise within the experimental equipment may be what is being observed.

What to make of this? Two things. First, we are trying to learn whether a particular experimental setup can do what its builders hope. Examining the apparatus is key to science, and it’s something that both the experiments and those reviewing the work take as a solemn responsibility. If the White-Juday Warp Field Interferometer doesn’t work as originally expected, this now gives the experimenters the opportunity to use this knowledge to add to their database, and possibly use it in refining future experimental efforts in this area.

Secondly, this entirely natural development of studying the apparatus and working out the implications doesn’t fare well when journalists jump to conclusions. It is entirely normal for ideas to be advanced in the give and take of conferences and scientific papers as researchers proceed with the dogged task of finding the truth. Journalism likes a good story, however, and the temptation to take tentative conclusions and make them sound permanent is irresistible. Thus we get headlines like The Washington Post‘s This is the amazing design for NASA’s Star Trek-style space ship, the IXS Enterprise.

Sonny White, who is the kindest of men, is a friend, and every time I’ve talked to him about these matters he has pointed out to me how much he deplores the hype that accompanies work in these areas. Sonny would like there to be a way to get to a warp drive and so would I, and he may well want to rebut the paper above with a new analysis of his own. So the work proceeds, but it should always do so with the understanding that ideas can be blown far out of proportion in the era of a global Internet and a willingness to go for the big story rather than the considered truth. The truth here is that we are in a process of learning what works and what does not.

Enter the Quantum Vacuum Thruster

So we need to calm down. Over the past few days there has been a flare-up about so-called quantum vacuum thrusters, following a story in Wired that made several bold statements, such as the title: NASA Validates ‘Impossible’ Space Drive. It is true that Eagleworks tested a quantum vacuum thruster device, a ‘propellant-less microwave thruster’ which was developed by Guido Fetta. The work on what Fetta calls the ‘Cannae Drive’ was presented in late July at the 50th Joint Propulsion Conference in Cleveland. Independent of this effort, British scientist Roger Shawyer has been working on a similar thruster for years, one recently tested by a team in China.

I always appreciate it when people send me interesting links, and a number of readers passed the Wired story along. I can certainly understand their interest! For the propellantless thruster seems to violate the principle of conservation of momentum, a very big thing if true, and it’s also true that a drive that could do these things could lead to entirely new designs in propulsion. There is no sense, however, in which NASA could be said to have ‘validated’ this device.

Gizmodo popped up with a headline of its own, making the bald statement: NASA: New “impossible” engine works, could change space travel forever. The article also tells us: “the fact is that the quantum vacuum plasma thruster works and scientists can’t explain why.”

But does it work? To know, we would need to study the experimental apparatus carefully to make sure there were no effects happening within it that could replicate the minute perceived signal. In other words, we may be looking at equipment noise. My sources, which I consider highly reliable, tell me that a review of the equipment used in the JSC quantum vacuum thruster tests has been completed but because it has not yet been released, I cannot make a comment on it beyond saying that it will likewise upgrade our understanding of the kind of experiment that was run, and how valid the results might be.

I would love to see the emergence of a genuine ‘impulse’ engine of the sort that the media have written about and would rejoice in its implications. But we are part way into a complicated story that has reached no conclusion. Fortunately, several media stories have also appeared that have begun to take a more probing look at these matters, such as A New Thruster Pushes Against Virtual Particles!…or is a Lab Error in io9. Mika McKinnon noted that the testing of the Cannae drive was reported in a conference paper and presentation, a setting where preliminary results are often announced on work that is ongoing. Quoting McKinnon:

As someone who has done my fair share of novel research that didn’t go exactly as expected, this conference abstract reads like the researchers were looking for extra eyeballs to figure out what about their testing rig might be flawed — not a grand announcement of a spectacular breakthrough. This has the potential to be cool, but at the moment, about the strongest thing that it’s scientifically responsible to say about these test results is that the researchers need to revise their testing setup.

We also have sound advice in an article called Don’t buy stock in impossible space drives just yet from Ars Technica, and an essay in Popular Science quoting Michael Baine, chief of engineering at Intuitive Machines:

“Whenever you get results that have extraordinary implications, you have to be cautious and somewhat skeptical that they can be repeated before you can accept them as a new theory,” Baine says. “Really, it’s got to come down to peer review and getting that done before you can get any kind of acceptance that something exotic is going on here.”

The Chinese team in Xian claims results that back the quantum vacuum thruster idea. Let’s put their analysis under the same level of scrutiny. We have no choice in this, because finding a hole in conservation of momentum would be a result so unexpected that we can expect any laboratory producing such results to undergo examination about its methodology. We can also expect papers undergoing peer review that defend the findings. All of that would jibe with scientific method aimed at ferreting out the truth. But getting ahead of ourselves when we’re only part way into the story can only lead to confusion. As I said above, other shoes are about to drop on the quantum vacuum thruster story, and when they do, we’ll look at them with equal interest.

I love “The Boxer.” And when I think about how some in the media react to advanced propulsion stories, its lyrics keep coming to mind. Here’s the complete first verse:

I am just a poor boy.
Though my story’s seldom told,
I have squandered my resistance
For a pocketful of mumbles,
Such are promises
All lies and jest
Still, a man hears what he wants to hear
And disregards the rest.

I’m a writer and journalist, not a scientist. But the researchers I talk to are taken aback by the wave of hype that has accompanied many recent advanced propulsion stories. Let’s hope a bit of caution seeps in, for scientific breakthroughs do not come easily. If we are on the edge of one, which I seriously doubt, the matter will resolve itself because more and more data will be accumulated, subjected to review, and put through rigorous testing. What we want to hear is not what’s important. The universe parcels out its answers according to what is true.

Ever wonder what it would have been like to sit in on a great occasion? I used to think about this in relation to a dinner party the painter Benjamin Haydon threw in 1817 at his London studio. At the ‘immortal dinner’ were, among others, William Wordsworth, John Keats and Charles Lamb, leading literary figures of their day. Fortunately, gatherings like these aren’t relegated to the 19th Century. In a piece that ran originally in The New York Review of Science Fiction, Gregory Benford describes an equally extraordinary evening with some of the greatest minds of our time: Martin Rees, Stephen Hawking, and Paul Dirac. A physicist and award-winning science fiction writer, Benford relates the particulars of a Cambridge sabbatical as scientists at the top of their form meet for an evening of bonhomie, whimsy and reflection.

by Gregory Benford

In science one tries to tell people, in such a way as to be understood by everyone, something that no one ever knew before. But in poetry, it’s the exact opposite.

–Paul Dirac

The invitation was on heavy bond in a delicious oyster color. I opened the Trinity College envelope noting it bore no stamp, apparently placed in my Institute of Astronomy mailbox by hand. Flowing script invited my wife Joan and me to evening meal with Professor Martin Rees.

Very good; the full High Table college show, then. In 1976 I was on sabbatical as a visiting fellow in Cambridge, England. I went there to study pulsars where they’d been discovered, but quickly became more interested in the luminous jet just seen in radio frequency maps of M87, the nearest active galaxy.

Martin Rees was then the Plumian Professor of physics and the director of the Institute of Astronomy, appointed just after the departure of Fred Hoyle. He had agreed to host my sabbatical, a stay that began my astrophysics career; I’ve spent the decades hence mostly on pulsars and galactic jets. In Cambridge I learned much more than I anticipated.

Precisely on time Joan and I walked through the Great Gate, the main entrance to the college, leading to the yawning Great Court. In the centre of the court stood an ornate fountain, traditionally fed by a pipe from Conduit Head in west Cambridge, not the unreliable Cam River nearby. A solemn porter in a black bowler hat welcomed us, remarking gruffly on the chilly air, and nodding at the invitation as I presented it. “Ah, the Rees room.”

Image: Cosmologist and astrophysicist Martin Rees, whose books and lectures explore not only astronomy but the bounds of science, philosophy and humanity’s place in the cosmos.

Trinity College undergraduates passed in gowns of dark blue. A statue of the college founder, Henry VIII, greeted us from a shadowy niche above the doorway. Martin Rees stood beside it, a slight man with a hawk nose and incisive gaze, bowing to Joan with a broad smile. I imagined we’d eat at the high table, as I had before for lunch, but instead Martin took us into a private dining room. I walked in with Joan and saw at the table two men and their wives: Paul Adrien Maurice Dirac and Stephen Hawking. Martin had said nothing to alert us.

Newton, Nehru and Maxwell were alumni of Trinity, and Dirac stood in such company; soon, so would Hawking and Rees.

The dining room was small, with room for six at the table. Soft lighting cast glows on the dark wood walls amid the scene of 700 years of academic elitism. The leadened plates stamped with the famed Trinity monogram framed a small salad. The flatware was heavy, dark silver and tall stemmed glasses ranked to the side. The servers wore formal tuxedo styled clothes and professionally disinterested faces. The headwaiter handled all dishes with white gloves and led the two solemn under-waiters.

I said very little through the salad, letting Joan carry our side. She entertained them with stories to adapting to English home appliances, her tinkling laughter softening the atmosphere. I reflected. Dirac had won a Nobel in 1933 for the first relativistic theory of particles, the Dirac equation. “The great papers of the other quantum pioneers were more ragged, less perfectly formed than Dirac’s,” my friend Freeman Dyson had said to me when I was in graduate school. Freeman had taken Dirac’s Cambridge quantum mechanics course as a precocious 19-year-old. Of Dirac’s discoveries, Freeman said, “His papers were like exquisitely carved marble statues falling out of the sky, one after another. He seemed to be able to conjure laws of nature from pure thought.”

This is an evening to keep your mouth shut, I thought, sitting at the centuries-old table and sipping a light Chardonnay (French, of course) served with the salad. Next, a tasty soup arrived, attended in strict silence by the stiff waiters. I noted that the French red wine was older than I was, a 1938 from the Fellows’ Cellar. A Haut Medoc, it was deep and rich with a surprising plum aftertaste.

Famously, Dirac’s wife Manci spoke little, and he even less. His colleagues in Cambridge jokingly defined a conversational unit of a dirac — one word per hour. Rees had related to me already how a while back all the physicists in Cambridge had newborn daughters, and someone said, “There must be something in the air.” Without pause Dirac, who had two daughters, said, “Or in the water.”

Dirac was a slight man and autistic, widely known as hard to draw out. He said this concentration proved crucial to his success as a theoretical physicist, for he could remain focused on a problem for a long time. He also could order information about mathematics and physics in a systematic way, employing his visual imagination and determination. (Decades later, I saw medical practice focus on this supposed disorder, “fixing” it with drugs and therapy. How many geniuses have we lost this way?)

I asked him how he concentrated solely on his research. “I don’t talk,” he said with admirable brevity and a smile. He also said he only stopped work on Sunday, when he took long strolls alone. He had struggled to find the Dirac equation for months, getting nowhere, then took his usual Sunday walk—and the entire solution came to him when he was crossing a small bridge. He hurried to a nearby pub, asked for lunch and wrote the equation on the back of the menu so he would not forget. He seldom looked directly at anyone, but this time he stared me in the eye. “There it was, out of nowhere.”

Image: Nobelist Paul Dirac, a founder of quantum mechanics and quantum electrodynamics, who predicted the existence of antimatter.

“Do you still have the menu?” I asked, eyes wide. When I said it would be a charming historical momento, he dismissively waved his hand. He had used it to start a fire in his chilly college rooms.

The Navy bean soup done, talk moved on. Some mention of English politics arose, at a time when Maggie Thatcher was moving to the fore, Martin squelched with, “I’m entirely infra-red,” which meant something like Trotsky. He had no wife then. Hawking’s wife rolled her eyes at this statement, saying nothing.

As the waiters smoothly placed plates of veal ala brochard before us, Hawking changed the tone of the conversation with his halting words. He wanted to talk about science fiction. Martin had told him I wrote the stuff. I’d had the impression that at Cambridge science fiction was something serious scientists never would do, and seldom discuss — especially at a table where Newton changed the world over bowls of steaming lentil soup—and I said so. Hawking gave a slanted grin. “Fred Hoyle has left us, but he is not forgotten.”

Hawking talked in slurred tones about what we now call his “chronology protection conjecture”. Why does nature apparently abhor a time machine? He said, “It seems that there is a Chronology Protection Agency which prevents the appearance of closed timelike curves and so makes the universe safe for historians.”

Martin pointed out that there was strong experimental evidence in favor of the conjecture — from the fact that we have not been invaded by hordes of tourists from the future. All this discussion Hawking eventually included in a book in the 2000s, along with his fears that our TV broadcasts, would bring ravening aliens to our door. He thought about such speculations in the 1970s, but apparently kept them largely to himself during his climb to fame.

Image: Theoretical physicist Stephen Hawking, famous among many things for his work on black holes and general relativity. Like Dirac, he held Cambridge’s Lucasian professorship of mathematics.

Dirac spoke about the walks he took around Cambridge, relating favorite routes in great detail, but otherwise had no small talk. Slowly Hawking turned the conversation around to what books we read, asking each of us. He then announced that since he was thirteen he had never bothered with the assignments in Literature classes, preferring science fiction. Dirac remarked, “In science one tries to tell people, in such a way as to be understood by everyone, something that no one ever knew before. But in poetry, and I suppose in fiction, it’s the exact opposite.”

To my surprise Rees assented. “But science fiction leads to science,” he said. Dirac was silent and looked puzzled.

Stephen spent a long while relating memories of sf short stories he’d read. Like many fans, Hawking could recall ideas but not authors or titles. He was a big Robert Sheckley fan, I deduced, from what his remembered plots. Rees said he thought science fiction was like a literary dialect. It had its own vernacular and insider terms, its unusual pronunciation patterns and rhythms. A native sf “speaker” uses the argot of an audience, one that knows what Delany later called the sf reader protocols – signals of broader meaning. A good example is, “The door dilated,” implying a changed world. Nods all round, though Dirac said he had read little sf beyond Wells and Brave New World. “Perhaps I should.”

We all agreed that aliens in fiction serve as a distorting mirror to show what humankind is not. Hawking spoke with jerky gestures, fighting the erosions from his Amyotrophic Lateral Sclerosis, which I knew as Lou Gehrig’s disease. His speech was slurred, brief and almost unintelligible, his conciseness a skill that later worked well in A Brief History of Time. Hawking’s fame was rising on his striking research ideas–that empty space wasn’t empty after all, and black holes aren’t black.

His wife, with her tight, focused look, scoffed at ideas like aliens, likening them to imaginary beings. Stephen retorted tartly that so were angels. A sudden silence around the table. I sipped the wine, which was excellent and still blossoming with rich new tones. This incident prefigured the issue of her Baptist faith versus his firm atheism, which eventually split them up.

I recalled this evening lately, looking over notes I made that very evening. My wife Joan died of cancer in 2002. In 2005 Rees was elevated to a life peerage, sitting as a crossbencher in the House of Lords as Baron Rees of Ludlow, a seat in the County of Shropshire. By then Astronomer Royal, he told the British Interplanetary Society, ‘”It is better to read first-rate science fiction than second-rate science; it’s no more likely to be wrong and is far more stimulating than second-rate science. And I think it’s good to read the great classics of science fiction.”

After a five course meal we had the finishing treat: an English, less sweet, version of crème brûlée, known as “Trinity burnt cream.”

Now Martin is master of Trinity College and the best known astronomer in the world. Recently, in Our Final Hour, he predicted that one of the two following outcomes is inevitable for humanity:

Extinction from runaway effects of new technology (nanotechnology, robotics) or else from uncontrolled scientific research; terrorist or fundamentalist violence; or destruction of the biosphere;

or else

Our expansion into space, survival through colonization. He now advocates free markets and believes that the wealthy will push back the frontiers of space.

Not infra-red any longer.

I never saw Dirac again, but have kept up with Hawking and Rees through the decades, visiting Cambridge often. They both use science fiction in their popular writing, whereas in the 1970s that was not the sort of thing you mentioned at High Table. Our world has changed, partly because of those men.

What distinguished them the most, I think, was their quiet verve, their wish to grapple with life. They were eager to deal with whatever came at them. Dirac probed our fundamental understanding of the world in his monk-like solitude. Hawking persevered against his crippling disease to become a major cosmologist. Rees cannily wove his way into great power, urging the Institute for Astronomy to the forefront of the field, becoming Astronomer Royal, and a major figure bringing science to the public as well.

The evening left a deep impression on me. On the walk home, I remarked to my wife that I would probably never have a better evening–at least, with my clothes on. She took that as a challenge and made the evening even more so.

From my time there I gathered background that eventually appeared in my 1980 novel Timescape, which explores how scientists confront the unknown. Cambridge is steeped in tradition, but its scientific culture is radical. I hope it remains so.

Copyright 2013 by Gregory Benford