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Prophecy, Prediction and Starflight

I’m looking forward to the upcoming Starship Congress hosted by Icarus Interstellar, which will take place in Dallas from August 15th to the 18th at the Hilton Anatole. With an audience of physicists, engineers and researchers of all kinds, this is a chance to catch up with old friends and firm up relationships that have in some cases been pursued solely through email. 2013 may be remembered as the year of the conference in interstellar terms, since we had the Tennessee Valley Interstellar Workshop in February, Starship Century in May, Starship Congress coming up in August, then the 100 Year Starship Symposium in Houston from September 19th to the 22nd.


This doesn’t include smaller events like the British Interplanetary Society’s excellent Philosophy of the Starship gathering in late May, and if you’re in range of BIS headquarters in London, it’s worth checking out what’s coming up on their always active schedule. But thoughts of indefatigable activity on the interstellar front always bring me around to Richard Obousy, president of Icarus Interstellar, who appears in a short piece titled Incredible Technology: How to Make Interstellar Spaceflight a Reality, along with Tau Zero Founder Marc Millis. Obousy is, in the best sense, an interstellar optimist.

Image: Richard Obousy, a tireless interstellar advocate now preparing for Starship Congress.

It was in Huntsville for the Tennessee Valley event that I heard Obousy use a phrase he repeated for Space.com’s Mike Wall: “I think a lot of people tend to overestimate what we can accomplish in the short term, in the next five to 10 years. But they also vastly underestimate what we can accomplish in the long term, decades or a century from now.” And that’s right on the money, because when we look ahead just a few years, we often see trends we think will accelerate, but over the long-term it’s often the factors we hadn’t yet considered that make all the difference.

I catch the same optimism in Marc Millis, who as former head of NASA’s Breakthrough Propulsion Physics project knows what it is like to be cut off at the knees by funding problems. Millis thinks the discovery of an Earth-like planet around another star will be a motivator for public engagement with space, resulting in the kind of interest that could spur demand for new exoplanet observatories and, we can hope, funding to support progress in propulsion. Advances in computer technology and the growth of commercial spaceflight, particularly through asteroid mining ventures that will extract resources and return them to Earth, should also help.

Obousy’s observation about underestimating what can happen over the long haul gibes with what David Deutsch argues in The Beginning of Infinity (Viking, 2011). Deutsch distinguishes between ‘prophecy’ and ‘prediction’ when talking about the future, prophecy being the discussion of things that are simply not knowable, whereas prediction involves conclusions that are based on good explanations. When we try to know the unknowable, we create a bias toward pessimism because we cannot know the shape or reach of future knowledge.

The growth of knowledge cannot change that fact. On the contrary, it contributes strongly to it: the ability of scientific theories to predict the future depends on the reach of their explanations, but no explanation has enough reach to predict the content of its own successors – or their effects, or those of other ideas that have not yet been thought of. Just as no one in 1900 could have foreseen the consequences of innovations made during the twentieth century – including whole new fields such as nuclear physics, computer science and biotechnology – so our own future will be shaped by knowledge that we do not yet have. We cannot even predict most of the problems that we shall encounter, or most of the opportunities to solve them, let alone the solutions and attempted solutions and how they will affect events. People in 1900 did not consider the Internet or nuclear power unlikely: they did not conceive of them at all.

Thus it may well be that the solutions we find in 2100 to problems that plague us today will come from directions we have yet to imagine. And I think the Icarus organizers are doing the smart thing by arranging their Starship Congress around time tracks: What can be done in the short-term to accelerate the progress of deep space research? What will be needed 20 to 50 years from now to achieve interstellar goals? And what can we say about longer timescales?

The interface between prediction and prophecy is a challenging place, demanding shrewd analysis and a mind open to possibility. Understanding how short-term prediction can turn into long-term prophecy reminds us of how easy it is to make blanket statements that are invalidated as new knowledge becomes available. Think of Albert Michelson’s address at the University of Chicago in 1894, when he argued that “The more important fundamental laws and facts of physical science have all been discovered, and these are now so firmly established that the possibility of their ever being supplanted in consequence of new discoveries is exceedingly remote… Our future discoveries must be looked for in the sixth place of decimals.”

Thus the view from 1894, with quantum theory and relativity looming in the near future. Deutsch would say that the physics of that year was not able to predict the content of its successors, that in fact it was not capable even of imagining the kind of changes quantum theory and relativity would bring. Comments like Michelson’s should keep us humble as we look ahead.


Millis makes much the same point in Mike Wall’s article. He’s been describing the kind of technologies under investigation for advanced propulsion, which include nuclear fusion, solar and beamed-energy sails, antimatter engines and interstellar ramjets. But as he tells Wall, none of these alternatives other than solar sails are even close to being flight-ready. Even the sails we’ve launched are experimental and far smaller than what would be needed for interstellar flight, nor have we any experience in accelerating actual sails in space through beamed energy.

But we want to move forward, and Millis thus advocates “a reasonable portfolio, a small amount spread over everything from the seemingly simple solar sails to the seemingly impossible faster-than-light [engines], and the things in between.” The goal should be to move forward through a series of achievable milestones to build momentum and attract funding. Or as Lao Tzu once put it, “You accomplish the great task by a series of small steps.”

Image: Interstellar researcher and Tau Zero founder Marc Millis.

We don’t know which propulsion option will be the one to take us to the stars, but as Deutsch would remind us, we don’t even know whether the one that actually succeeds is on our current list, because we may not have conceived of it yet. Something the philosopher Karl Popper once said sticks with me. This is from his The Myth of the Framework (Routledge, 1996):

The possibilities that lie in the future are infinite. When I say ‘It is our duty to remain optimists,’ this includes not only the openness of the future but also that which all of us contribute to it by everything we do: we are all responsible for what the future holds in store. Thus it is our duty, not to prophesy evil but, rather, to fight for a better world.


Comments on this entry are closed.

  • Alex Tolley July 10, 2013, 10:13

    ““I think a lot of people tend to overestimate what we can accomplish in the short term, in the next five to 10 years. But they also vastly underestimate what we can accomplish in the long term, decades or a century from now.””

    Pretty much what Clarke said in Profiles of the Future?. The reason is that humans have difficulty thinking in exponential or geometric progression. For example, I have been quite astounded at the rapid improvement in speed and cost of gene sequencing. I suspect that most commentators underestimate the likely development and impact of 3-D printing and related technologies (unless they are indulging in breathless hype).

    “…Albert Michelson’s address at the University of Chicago in 1894…”

    His timing was impeccably poor. Next year Roentgen discovered x-rays and 4 years later, the Curies discovered Radium. Is physics in a similar position today with the standard model, yet with unexplained (AFAIK) phenomena like dark energy?

  • Mark July 10, 2013, 12:49

    “The growth of knowledge cannot change that fact. On the contrary, it contributes strongly to it: the ability of scientific theories to predict the future depends on the reach of their explanations, but no explanation has enough reach to predict the content of its own successors …”

    I don’t think scientific theories predict the future, at best, they hope to predict the outcome of observations of the processes encompassed by the theory.

  • Astronist July 11, 2013, 4:00

    My own take on this is that it is not plausible to imagine that science and technology are capable of infinite progress. Advances in complexity have historically come in quantum jumps: from chemistry to prokaryotic cells, then later to eucaryotic cells, then later to multicellular life, now to technology-enabled life. (There does exist, however, a contrary view, which points to the acceleration in the timescales, implying that whatever comes after science/technology will come very quickly, as if part of the same exponential curve.)

    We are therefore in danger of making the same mistake that Michelson did. He extrapolated the future from what he knew, and missed the imminent exponential growth in science/technology. We are now tempted to extrapolate from what we know, and assume that the brief burst of exponential growth of the past 300 years will continue indefinitely into the future, or at least until we have powers “indistinguishable from magic”. But if there is a scientific/technological plateau awaiting us, then equally we are unable to predict where that comes, whether we are already decelerating onto the plateau (consider slow progress in controlled nuclear fusion and in commercialising space travel), or whether that plateau will not come until after we have FTL travel, superintelligent computers, personal immortality and a cure for cancer.

    Oxford, UK

  • Ronald July 11, 2013, 4:40

    For some reason, while reading this post, I had to think of the beautiful quote from Jonathan Livingston Seagull:

    “You will begin to touch heaven, Jonathan, in the moment that you touch perfect speed. And that isn’t flying a thousand miles an hour, or a million, or flying at the speed of light. Because any number is a limit, and perfection doesn’t have limits. Perfect speed, my son, is being there.”

    This quote keeps moving me.

  • David Cummings July 11, 2013, 7:32

    I remember reading about a conference sometime in the early 1900’s, not long before the 1905 papers of Einstein, in which a gathering of physicists proclaimed again (possibly echoing Michelson) that all the problems of physics had been solved and that there were only two small clouds in an otherwise bright and sunny sky:

    1. The inability to measure variations in the speed of light as we moved through the ether.
    2. The “black body problem” and the inability to explain that as the object was heated it radiated different colors at different temperatures.

    Of course, the first “small cloud” became Relativity. The second Quantum Mechanics.

    It’s easy for us to look back and laugh now, but it took an Einstein and a Planck to give us the answers.

  • A. A. Jackson July 11, 2013, 8:13

    “His timing was impeccably poor. Next year Roentgen discovered x-rays and 4 years later, the Curies discovered Radium. Is physics in a similar position today with the standard model, yet with unexplained (AFAIK) phenomena like dark energy?”
    I don’t know or have not read a scientist worth his salt , in last 50 year or more, say what Michelson did (actually I don’t think he was alone at the time in holding this opinion.)
    The Higgs Boson has probably been discovered, but we don’t know what kind of Higgs Boson there are several models. In 2015 when the LHC is operating at twice it’s initial energy if we don’t see Super Symmetry particles then theoreticians have a whole new mystery to solve.
    Of course the Standard Model does not contain gravity, the hierarchy problem about that is still a brick wall.
    Dark Mass and Dark Energy are empirically measured, yet physics has no way to really model them.
    So no physicist , today, would utter Michelson’s statement today.

    “People say to me, “Are you looking for the ultimate laws of physics?” No, I’m not… If it turns out there is a simple ultimate law which explains everything, so be it — that would be very nice to discover. If it turns out it’s like an onion with millions of layers… then that’s the way it is. But either way there’s Nature and she’s going to come out the way She is. So therefore when we go to investigate we shouldn’t predecide what it is we’re looking for only to find out more about it. Now you ask: “Why do you try to find out more about it?” If you began your investigation to get an answer to some deep philosophical question, you may be wrong. It may be that you can’t get an answer to that particular question just by finding out more about the character of Nature. But that’s not my interest in science; my interest in science is to simply find out about the world and the more I find out the better it is, I like to find out…”
    — Richard Feynman

  • Jean-Pierre Le Rouzic July 12, 2013, 16:40

    Michelson was wrong but Special Relativity didn’t bring any technology jump either in the years after the 1905 paper. And without Michelson there would never have any Special Relativity as nobody would have found that facts were not in accord with the current theory. Actually SR and GR are not so useful in our modern lives when compared to thermodynamic or solid state physics.

    I believe that all the technologies as well as real science are only created by brilliant experimenters, so what we may need for interstellar exploration is not the so called “armchair theorist” but some hackers, crazy enough to explore uncharted or neglected territories and smart enough to apply the old and trusted scientific method to her/his findings.

  • Ole Burde July 17, 2013, 6:13

    ” I think a lot of people tend to overestimate what we can accomplish in the short term, in the next five to 10 years. But they also vastly underestimate what we can accomplish in the long term, decades or a century”
    This statement could be true or false , depending on what will actualy be acompished in the future. In order for it to become true , the developing comunity of ” space enthusiasts” will have to proove its staying power , its ablity renew itself and grow stronger . In the long run this canot be done without developing effektive and inclusive social intitutions ..perhabs not exacly a political party but more like a ”youthmoovement ” or even better a totally new kind of something-moovement …
    In orde to sucseed we have to use ALL the tool in the box , including even the as-yet nonexact social sciences.

  • Adam July 21, 2013, 1:41

    I too have doubts about whether we can continue the geometric progression of our science and technology, because we’ll hit real-world barriers like limited energy and material resources (on our Earth or in our solar system) and light speed itself. As smart as we become, there may be no getting around the fact that it could take a million years or more to colonize our galaxy and that more distant colonies will be effectively cut off from each other because there will be no practical way to maintain contact across such large distances.

  • ljk July 29, 2013, 19:30

    Faster Than the Speed of Light?

    Michael Stravato for The New York Times

    Harold G. White, a NASA physicist, is working on the concept of warp drive, like on “Star Trek.” Some of the original series’ ideas fit into the new warp field theories, like the round shape of the engines in the rendering.


    Published: July 22, 2013 346 Comments

    HOUSTON — Beyond the security gate at the Johnson Space Center’s 1960s-era campus here, inside a two-story glass and concrete building with winding corridors, there is a floating laboratory.

    Harold G. White, a physicist and advanced propulsion engineer at NASA, beckoned toward a table full of equipment there on a recent afternoon: a laser, a camera, some small mirrors, a ring made of ceramic capacitors and a few other objects.

    He and other NASA engineers have been designing and redesigning these instruments, with the goal of using them to slightly warp the trajectory of a photon, changing the distance it travels in a certain area, and then observing the change with a device called an interferometer.

    So sensitive is their measuring equipment that it was picking up myriad earthly vibrations, including people walking nearby. So they recently moved into this lab, which floats atop a system of underground pneumatic piers, freeing it from seismic disturbances.

    The team is trying to determine whether faster-than-light travel — warp drive — might someday be possible.

    Warp drive. Like on “Star Trek.”

    Full article here:


  • ljk July 30, 2013, 10:18

    Experimental quest to test Einstein’s speed limit

    by Staff Writers

    Berkeley CA (SPX) Jul 30, 2013

    Left to right, Dmitry Budker, Nathan Leefer and Michael Hohensee with their experiment to test Einstein’s speed limit. Photo by Andreas Gerhardus.
    Albert Einstein’s assertion that there’s an ultimate speed limit – the speed of light – has withstood countless tests over the past 100 years, but that didn’t stop University of California, Berkeley, postdoc Michael Hohensee and graduate student Nathan Leefer from checking whether some particles break this law.

    The team’s first attempt to test this fundamental tenet of the special theory of relativity demonstrated once again that Einstein was right, but Leefer and Hohensee are improving the experiment to push the theory’s limits even farther – and perhaps turn up a discrepancy that could help physicists fix holes in today’s main theories of the universe.

    “As a physicist, I want to know how the world works, and right now our best models of how the world works – the Standard Model of particle physics and Einstein’s theory of general relativity – don’t fit together at high energies,” said Hohensee of the Department of Physics. “By finding points of breakage in the models, we can start to improve these theories.”

    Full article here: