Like many geeks of the post-Sputnik generation, I grew up hoping that space travel would be common by the time I reached middle age. Weaned on a youthful diet of speculative fiction by the likes of Ray Bradbury and Arthur Clarke, raised on Star Trek and The Outer Limits, and thrilled by real-life hero Neil Armstrong’s “one small step” onto the gravelly surface of the Moon when I was in elementary school, it never occurred to me that humankind’s manifest destiny in the stars would be undone by changing political winds, disasters like the Challenger explosion, and a mountain of debt to pay for misguided military adventures like the War in Iraq.
It’s true that, in some ways, we’re living in a new golden age for space nerds. Bard Canning’s gorgeously enhanced footage of Curiosity’s descent to Mars — made instantly available by the global network we built instead of a Hilton on the Moon — certainly beats grainy snippets beamed down from Tranquility Base. A newly discovered exoplanet that “may be capable of supporting life” seems tomake headlines every few months. Cassini’s ravishing closeups of Saturnregularly put the fever dreams of ILM’s animators to shame. But wasn’t I supposed to be “strolling on the deck of a starship” by now, as Paul Kantner’s acid-fueled hippie space epic Blows Against the Empire promised me when it was nominated for a Hugo award in 1971?
The problem, it turns out, isn’t just a loss of political will to finance manned space flight. Rocket science turns out to be rocket science — not easy, and constrained by some very real limitations dictated by material science, the physics of acceleration, and the unwieldy economics of interstellar propulsion. Until a real-life Zefram Cochrane comes along to invent a practical warp drive, I may not be sightseeing on any Class M planets anytime soon.
One of the best briefings on the state of the art of interstellar exploration is Lee Billings’ essay “Incredible Journey,” recently reprinted in a wonderful new anthology called The Best Science Writing Online 2012, edited by Scientific American’s Bora Zivkovic and Jennifer Ouellette. I’m very honored to have a piece in the anthology myself: my NeuroTribes interview with John Elder Robison, author of the bestselling memoir of growing up with autism, Look Me in The Eye, and other books. When SciAm’s editors suggested that each author in the book interview one of the other authors, I jumped at the chance to interview Billings about his gracefully written and informative article about the practical challenges of space flight. Billings is a freelance journalist who has written forNature, New Scientist, Popular Mechanics, and Seed. He lives outside New York City with his wife, Melissa.
Steve Silberman: Before we even get into the meat of your piece, I want to mention how impressed I was by the power and lyricism of your writing. Phrases like “the cosmos suddenly becomes less lonely” and “the easiest way the Daedalus volunteers found to fuel their starship was, in effect, the industrialization of the outer solar system” make vast and highly abstract concepts immediately comprehensible and visceral to lay readers. What made you want to become a science writer, and who are your role models for writing, in any genre?
Lee Billings: My attraction to science preceded my attraction to the act of writing, perhaps because, like every child, I was intensely curious about the world around me. Science, more so than any other source of knowledge I could find, seemed to change the world into something at once eminently understandable and endlessly mysterious.
I became interested in science writing, science journalism, at approximately the same time I realized I would make a poor scientist. I was midway through my college prerequisites, thinking I was on a path to a career in neuroscience. I’d been having a lot of trouble with the more quantitative courses — calculus, organic chemistry, and so on. Many of my friends would ace their assignments and tests after sleeping through lectures and rarely cracking a book. I would study hard, only to receive poor grades. Meanwhile I was breezing through courses in English, literature, history, and art. After a particularly fervent all-night cram-session for a final exam that I still almost flunked, I decided if I wasn’t destined to excel within science itself, perhaps I could instead try to make my mark by helping communicate the world-changing discoveries scientists were making. So I switched my academic emphasis from neuroscience to journalism, and became something of a camp follower, scavenging and trailing behind the gifted few at the front lines of research. I’ve never looked back, and have no regrets. The job never gets old: Rather than being at best a mediocre, hyper-specialized bench worker, being a science writer lets me parachute in to varied fields on a whim, and invariably the brilliant individuals I find upon landing are welcoming and happy to talk to me.
As for influences… I still have a long way to go, but if my writing ever comes to possess a fraction of Carl Sagan’s charisma and elegance, John McPhee’s structure and eye for detail, Richard Preston’s depth of focus and cinematic flair, Stanislaw Lem’s imagination and analytic insight, or Ray Bradbury’s lyrical beauty, I will be a happy man.
Ray Bradbury’s “The Martian Chronicles”
Silberman: Several times a year now, we hear about the discovery of a new exoplanet in the “Goldilocks zone” that could “potentially support life.” For example, soon after he helped discover Gliese 581g, astronomer Steven Vogt sparked a storm of media hype by claiming that “the chances for life on this planet are 100 percent.” Even setting aside the fact that the excitement of discovering a planet in the habitable zone understandably seems to have gone to Vogt’s head at that press conference, why are such calculations of the probability of life harder to perform accurately than they seem?
Billings: The question of habitability is a second-order consideration when it comes to Gliese 581g, and that fact in itself reveals where so much of this uncertainty comes from. As of right now, the most interesting thing about the “discovery” of Gliese 581g is that not everyone is convinced the planet actually exists. That’s basically because this particular detection is very much indirect — the planet’s existence is being inferred from periodic meter-per-second shifts in the position of its host star. The period of that shift corresponds to the planet’s orbit as it whips from one side of the star to the other; the meter-per-second magnitude of the shift places a lower limit on the planet’s mass, but can’t pin down the mass exactly. So that’s all this detection gives you — an orbit and a minimum mass. That’s not a lot to go on in determining what a planet’s environment might actually be like, is it?
Now, get up and walk around the room. You’re moving at about a meter per second. Imagine discerning that same rate of change in the motion of a million-kilometer-wide ball of plasma, a star many light-years away. Keep in mind this star’s surface is always moving, in pounding waves and swirling eddies, in rising and falling convection cells, in vast plasmatic prominences arcing above the surface, often at many kilometers per second. At any particular moment, all that stellar noise can swamp the faint planetary signal. Only by building up hundreds or thousands of careful measurements over time can you get that crucial periodicity that tells you what you’re seeing might be a planet. So the measurement is quite statistical in nature, and its interpretation can change based on the statistical assumptions being used. This is further complicated by the fact that planets are rarely singletons, so that any given stellar motion may be the product of many planets rather than one, requiring careful long-term study to tease apart each world’s contribution to the bulk signal. It’s also complicated by the instability of astronomical instruments, which must be kept carefully, constantly calibrated and stabilized lest they introduce spurious noise into the measurements. In the case of Gliese 581g, not everyone agrees on the putative planetary signal actually being caused by a planet, or even being real at all — the signal doesn’t seem to manifest equally in the handful of instruments purportedly capable of detecting it.
So it’s very difficult to just detect these things, and actually determining whether they are much like Earth is a task orders of magnitude more difficult still. Notice how I’m being anthropocentric here: “much like Earth.” Astrobiology has been derisively called a science without a subject. But, of course, it does have at least one subject: our own living planet and its containing solar system. We are forced to start from what we know, planting our feet in the familiar before we push out into the alien. That’s why we, as a species, are looking for other Earth-like planets — they probably offer us the best hope of recognizing anything we might consider alive. It’s not the strongest position to be in, but it’s the best we’ve got. Calculating the probability of life on an utterly alien world outside the solar system for which we know only the most basic information — its mass, its orbit, maybe its radius — is at this stage a very crude guess. The fact is, we still don’t know that much about how abiogenesis occurred on Earth, how life emerged from inanimate matter. There are very good physical, chemical, thermodynamic reasons to believe that life arose here because our planet was warm, wet, and rocky, but we really don’t yet know all the cogent occurrences that added up to build the Earth’s earliest organisms, let alone our modern living world. A warm, wet, rocky planet may be a necessary but not a sufficient condition for life as we know it to form and flourish.
Lee Billings with planet hunter Geoff Marcy
This is really a chicken-and-egg problem: To know the limits of life in planetary systems, we need to find life beyond the Earth. To find life beyond Earth, it would be very helpful to know the limits of life in planetary systems. Several independent groups are trying to circumvent this problem by studying abiogenesis in the lab — trying to in effect create life, alien or otherwise, in a test tube. If they manage to replicate Earth life, the achievement could constrain just how life emerged on our own planet. If they somehow manage to make some single-celled organism that doesn’t use DNA, or that relies on silicon instead of carbon to build its body, or that prefers to swim in liquid ethane rather than liquid water, that gives us a hint that “Earth-style” biologies may only be one branch in a much larger and more diverse cosmic Tree of Life.
Silberman: Going deeper than the notion of the cosmos feeling “less lonely” – as well as the fact that we all grew up watching Star Trek and Star Wars and thinking that aliens are frickin’ cool (as long as they’re not the mama alien fromAlien) — why do you think people are so motivated to daydream about extraterrestrial life? What need in us do those dreams fulfill?
Billings: I don’t really think most people are necessarily motivated to daydream about just any sort of extraterrestrial life. It will probably take more than a microbe or a clam to excite most of our imaginations, even if that microbe happens to be on Venus or that clam happens to be on Mars.
I do think humans are motivated to daydream about extraterrestrial intelligence, and, to put a finer point on it, extraterrestrial “people.” They are motivated to dream about beings very much like them, things tantalizingly exotic but not so alien as to be totally incomprehensible and discomforting. Maybe those imagined beings have more appendages or sense organs, different body plans and surface coverings, but they typically possess qualities we recognize within ourselves: They are sentient, they have language, they use tools, they are curious explorers, they are biological, they are mortal — just like humans. Perhaps that’s a collective failure of imagination, because it’s certainly not very easy to envision intelligent aliens that are entirely divergent from our own anthropocentric preconceptions. Or perhaps it’s more diagnostic of the human need for context, affirmation, and familiarity. Why are people fascinated by their distorted reflections in funhouse mirrors? Maybe it’s because when they recognize their warped image, at a subconscious level that recognition reinforces their actual true appearance and identity.
More broadly, speculating about extraterrestrial intelligence is an extension of three timeless existential questions: What are we, where do we come from, and where are we going? The late physicist Philip Morrison considered SETI, the search for extraterrestrial intelligence, to be the “archaeology of the future,” because any galactic civilizations we could presently detect from our tiny planet would almost certainly be well more advanced than our own. It’s unlikely that we would ever receive a radio message from an alien civilization in the equivalent of our past Stone Age, and it’s unlikely Earth would ever be visited by a crewed starship that powered its voyage using engines fueled by coal or gasoline. Optimists consider this, and say that making contact with a superior alien civilization could augur a bright future for humanity, as it would suggest there are in fact solutions to be found for all the current seemingly intractable problems that threaten to destroy or diminish our species. It’s my opinion that most people think about aliens as a way of pondering our own spectrum of possible futures.
I’m inclined to believe some of the things Billings has to say in that it’s doubtful we’ll build anything like a starship in the near future and folks ( taxpayers ) just won’t fund those kinds of projects. Entrepreneurs such as Elon Musk, James Cameron and Peter Diamandis could in the future fund projects such as starprobes and starships – only if they prove profitable.
IMO it looks like stronger telescopes both on Earth and in space will be the only human built machines exploring the closer solar systems for any signs of life and extant civilizations because they can be economically constructed – and if they found anything interesting, the items are still a safe distance away.