If the Phone Doesn’t Ring, It’s Me

The line in the title above is from a Jimmy Buffett song. A friend who knows all Buffett songs line by line uses it on his answering machine, invariably provoking a chuckle when I ponder the implications. If the phone doesn’t ring, just what kind of message is being sent? Or is any message being sent at all? Thus does the singer capture the bewildered funk of romantic attachments, which can make hash out of all our logic. Like the dog that doesn’t bark (think Sherlock Holmes), the phone that doesn’t ring carries its own meaning, one we must now try to parse.

For the SETI phone isn’t ringing. If extraterrestrial civilizations are out there, is their silence a way of sending us a message? Alan Tough created a Web site with the express purpose of offering a communications venue to any nearby alien probes, spacecraft designed to study us and report home. The Invitation to ETI contains a number of essays explaining the project and more or less asking for participation by ET (Paul Davies’ contribution is titled If You’re Out There, ET, Log On!), but David Brin jogged my memory yesterday on a mailing list when he mentioned his own essay on Tough’s site, called An Open Letter to Alien Lurkers.

Wonderfully, what physicist and science fiction author Brin did in this essay is to discuss the reasons why ET might choose to remain silent. If the phone doesn’t ring, it may be because the species in question has a non-interference policy:

If you’ve monitored our TV, radio — and now our internet — perhaps you have a policy of noninterference for a different reason… in order to spare us and our culture from some harm that might come as a result of contact. An erosion of our sense of free will? Or our sense of having a high culture? We can understand this notion, too. Certainly the history of first contact between human cultures tells that the one with lower technology and sophistication often suffered ill effects.

If mercy motivates your reticence, we grasp the concept. Yet, this provokes a question — are you absolutely sure? Can you be certain we’re so fragile? Is it possible you might be mistaken? Or (again) perhaps rationalizing a decision that you made for other reasons?

A Safer Solution for Contact?

A solution would be not to phone but try the Internet, a safe course of inquiry because it can be performed via e-mail or anonymous participation in online discussion groups. Eccentricity would hardly be a drawback, for any such overtures would be met, at best, with amused tolerance, some people playing along with such messages out of curiosity and gamesmanship. Perhaps it’s happening today, opines Brin, or possibly ET writes science fiction stories under a pseudonym, hoping to tease our imaginations. If the latter is the case, the sad diminution is the number of well-paying short story markets for science fiction is grounds for concern.

Spiral galaxy

On the other hand: “Perhaps you even lace these works with special clues that can only be deciphered by purchasing and carefully reading every one of the purported author’s books…In hardcover, yet.” All of which gets across the tone of this delightful piece, one that confronts the SETI silence in provocative ways. Is the phone not ringing because any alien probe in our system is damaged and incapable of sending? Or because the extraterrestrial race is waiting for us to pass a particular milestone of development? If the latter, we could certainly use a hint.

Image: The spiral galaxy NGC 4414. Would alien astronomers within such galaxies search nearby stars for other civilizations, or would they look closer to home? Credit: NASA, The Hubble Heritage Team, STScI, AURA.

Brin lists eleven reasons for non-contact in all, including the possibility that the universe is dangerous enough to house berserker world-destroyers that might be programmed to make an end of civilizations on the rise. All the listed reasons go to the question of how little we know about the beings we hope one day to make contact with. If a SETI signal is ever received, should a response be sent immediately? The history of contact here on Earth between less technologically advanced cultures and those with superior tools has seldom ended well for those on the way up. So maybe the best strategy is considered silence until we work out the potential ramifications.

Exopsychology and Its Chances

Nonetheless, with powerful messages being sent to nearby star systems from the Evpatoria Planetary Radar in the Ukraine, NASA’s Deep Space Network sites in California, Spain and Australia, and the European EISCAT system in Svalbard (the latter to contain a Doritos ad!), the question of contact could conceivably be upon us before we have developed a widely accepted mechanism for response. And if Dr. Tough is right and a smart probe may have already been attracted to our area by radio, TV and radar signals pushing into interstellar space, then the phone that doesn’t ring becomes a psychological puzzler.

Exobiology is a science currently without specimens to study. In the same way, exopsychology is a perhaps hopeless but profoundly entertaining attempt to trace out alien motivations. I say hopeless because we bring all the assumptions grafted into our bipedal species over aeons of evolutionary development to the challenge. Can we hope to understand the assumptions a species with an entirely different line of growth would make as it confronts a civilization far beneath it technologically?

Perhaps not. Actual contact between humans and extraterrestrials may be so profoundly strange that we will have no real understanding of what has happened when and if the chasm is bridged. But then, the alien race may feel quite the same way. Brin’s eleventh and final reason for non-contact is that alien species might simply find us too weird to work with. All of which brings Leo Szilard’s response to Fermi when the latter asked his famous question to mind. Where are they? “They are among us,” said Szilard, “but they call themselves Hungarians.”

A Long-Term Bet on an Artifact

Contact or no, we do, at least, know where Allen Tough comes down on this. The Toronto-based researcher, now pursuing his interests in extraterrestrial life and the human search for meaning full-time, has an extensive background in both psychology and education that illuminates his thoughts on alien encounters. Tough has placed a bet on the Long Bets site that our first encounter with alien species or their artifacts will occur here in our Solar System. He makes no bones about the benefits of what we humans call a Bracewell probe:

“Most SETI scientists agree that any ETI we detect will likely be thousands or millions of years ahead of us (because our sun and our science are so young). Such an advanced society will likely have the capacity to build and launch cheap smart autonomous probes to explore the galaxy. Also, an advanced society will likely be motivated to send out exploratory probes. If such a probe were sent a few centuries ago to explore Earth, it will likely be here by now… I am betting that extraterrestrial intelligence, in one form or another, has already reached our solar system and will be confirmed first.”

The SETI League’s Paul Shuch is on the other side of the bet, not because he thinks Tough is necessarily wrong about those alien probes, but because detecting them will be so difficult if, indeed, they are there. “It’s a matter of instrumentation,” says Shuch, “and though we’ve gotten very good at intercepting electromagnetic waves, our record for detecting even nearby natural space debris is not too stellar (pun completely intentional).”

Those of us who suspect intelligent life is vanishingly rare in this or any other galaxy think this is a bet that may take quite a long time to be resolved, but searching for anomalies in the Solar System nonetheless makes good sense (maybe, as Hungarian-born Szilard implies, we should start the search in Budapest). After all, we’re completely in the dark when it comes to potential alien motivations or accomplishments. Thinking through what they might be, and the possibilities of a result close to home, is simply a matter of prudence and thoughtful engagement with the universe. If any of David Brin’s reasons for non-contact do apply, I for one want to find out which one it is.

Organics, Water in Protoplanetary Disk

We have interesting news coming up this week with regard to the first detection of methane in the atmosphere of an exoplanet, of significance because it demonstrates that we can detect organic molecules using spectroscopy in ways that will one day help us study the atmospheres of terrestrial worlds around other stars. More on this later in the week, after a NASA teleconference scheduled for the 19th. Today, though, let’s talk about another kind of detection in the circumstellar disk of a young star.

At work in the latter is the Spitzer Space Telescope‘s infrared spectrograph, which is being put to use to look at the composition of protoplanetary disks. Specifically, John Carr (Naval Research Laboratory) and Joan Najita (National Optical Astronomy Observatory, Tucson) have been examining gases in the planet forming region around the star AA Tauri, using refined methods that have allowed them to find the spectral signatures of three organic molecules: Hydrogen cyanide, acetylene and carbon dioxide, along with water vapor. Of some significance is the fact that these organics are more plentiful in the disk than in the cloud of interstellar gas from which the disk itself was formed. Says Carr:

“Molecular clouds provide the raw material from which the protoplanetary disks are created. So this is evidence for an active organic chemistry going on within the disk, forming and enhancing these molecules…Now that we can identify these molecules and inventory them, we will have a better understanding of the origins and evolution of the basic building blocks of life — where they come from and how they evolve.”

Data from AA Tauri disk

Image: This plot of infrared data shows the signatures of water vapor and simple organic molecules in the disk of gas and dust surrounding a young star. The data on the top line were captured by NASA’s Spitzer Space Telescope’s spectrograph, which collects light and sorts it according to color, or wavelength. In this case, infrared light from gases around the star AA Tauri was broken up into the wavelengths listed on the horizontal axis of the plot. The sharp spikes are called spectral lines, and each molecule has its own unique pattern, much like a fingerprint. The pattern of spikes reveals the signature of water vapor along with carbon dioxide, hydrogen cyanide, and acetylene–some of the basic building blocks of life. Credit: NASA/JPL-Caltech/Naval Research Laboratory.

450 light years from Earth, AA Tauri is thought to be less than a million years old. Carr and Najita are studying the region within three AU of the star, with results suggesting that water vapor is abundant in the inner part of the protoplanetary disk, which is where terrestrial planets may one day form. Meanwhile, a team at the California Institute of Technology has used Spitzer to examine two young stars, following up their observations with data from the Keck II telescope in Hawaii. Of that recently published work, Geoffrey Blake (Caltech) has this to say:

“While we don’t detect nearly as much water as exists in the oceans on Earth, we see essentially only the disk’s surface, so the implication is that the water is quite abundant. This is a much larger story than just one or two disks. Spitzer can efficiently measure these water signatures in many objects, so this is just the beginning of what we will learn.”

Thus the composition of planet-forming disks comes into greater focus in ways that may help us understand life’s potential for development. The AA Tauri paper is Carr and Najita, “Organic Molecules and Water in the Planet Formation Region of Young Circumstellar Disks,” Science Vol. 319. no. 5869 (14 March 2008), pp. 1504-1506 (abstract). The Caltech work, which has focused on the T Tauri stars AS 205A and DR Tau, is Salyk et al., “H2O and OH gas in the terrestrial planet-forming zones of protoplanetary disks,” slated to appear in the March 20 Astrophysical Journal (abstract).

Human Outcomes Among the Stars

Does transhumanism have a serious objective? The question resonates oddly yet provocatively given the stakes being considered. Augmenting the human frame potentially expands our powers, while the goal of uploading consciousness seems to offer a kind of immortality. These are surely desirable steps, but some versions of a posthuman future seem to point toward triviality, an existence within a simulated reality within a computational matrix, an awareness that sees no need to explore when simulation and observation can suffice. Can we avoid such a result?

I have a visceral, non-digital sense that a ‘singularity,’ if it occurs, will not include pushing minds evolved over eons to cope with a physical biosphere into digital frameworks. I doubt seriously that a human consciousness could make the adaptation — madness is the likely result. Hardly an expert on any of the relevant disciplines, I could well be wrong, but I noted Athena Andreadis’ thoughts on this issue in a recent entry on her Starship Reckless site. Here’s she’s talking about the first starship crews, surmising they may not represent a social or mental elite:

…the first generation of humans adjusted to starship living are far likelier to resemble Peter Watts’ marginalized Rifters or Jay Lake’s rabid Armoricans, rather than the universe-striding, empowered citizens of Iain Banks’ Culture. Such methods and outcomes will not reassure anyone, regardless of her/his position on the political spectrum, who considers augmentation hubristic, dehumanizing, or a threat to human identity, equality or morality. The slightly less fraught idea of uploading individuals into (ostensibly) more durable non-carbon frames is not achievable, because minds are inseparable from the neurons that create them. Even if technological advances eventually enable synapse-by synapse reconstructions, the results will be not transfers but copies.

Copies. The idea that I will be immortal fades with the thought that my human existence will end more or less the same way that of my ancestors’ did, either by accident or disease. The alternate take, that I may somehow cheat death through breakthrough advances in the science of medicine, makes more sense, but I suspect that even such long-term survivors will run into the limits of augmentation, which are imposed not by science but by evolutionary history.

I admit to remaining fascinated with the question despite my skepticism, and hadn’t thought it through from the space travel angle in quite the way Athena has. Do we have a human, biological future in interstellar space? If so, it surely must involve one of two things. Either we do develop a breakthrough technology for single-lifetime travel between the stars, or we take a lead from transhumanism by finding out just how far people can be altered to make potentially millennial journeys bearable. Such an outcome involves something Freeman Dyson has often written about, speciation. Widespread colonies lose contact with each other and breeding pools become isolated. The species changes over time, adapting anew as biological intelligence moves outward star by star.

I see that as an interesting and positive result, what Athena calls “…a Plurality of sapiens species and inhabited worlds…” In fact, I’m not sure the transhumanist community would necessarily disagree with that outcome, although I don’t see any great enthusiasm for space travel in much of what I read. Why travel to the stars when you can create an existence around your own star that becomes so computationally rich that any experience you might choose to have is within your grasp?

The answer is that our species is hardly monolithic, and as we move outward, it is less and less likely to be so. There was always some young dreamer in the average 18th Century port ready to sign up for a trip to the other side of the world, even if every friend he had planned to stay home. Sometimes he was the son of an admiral, planted there to gain experience for the naval career that awaited him. Other times he was a three-time loser on the run from problems imagined or real.

If we find a way to manage interstellar voyaging, will the scenario be any different? True augmentation of the species should emphasize its essential richness. We are dreamers and thieves and speculators and scholars, and some of us are travelers, at times unknowingly working for a common outcome that involves making life better even as we push outward. Ever the optimist, I have a sense that our species will survive in many forms, and that some of them will look back on our Solar System from a distant vantage indeed.

Time, Tides and Habitability

Keep your eye on Gliese 581. Not that the news is necessarily good for our hopes for habitability around that star — in fact, a recent paper suggests quite the opposite. The red dwarf exploded into the public consciousness with the announcement that one of its planets — Gl 581 c — could conceivably support clement temperatures and water at the surface, at least in places. But in exploring that possibility, we’re getting a case study of world-class science at work, analyzing data, offering hypotheses, broadening options. It’s an exciting process to watch.

Gl 581 d is now being analyzed for habitability, while Gl 581 c begins to appear less and less likely as a home to life. It may take decades and new space-based observatories for the issue to be resolved, but we now have a new take on Gl 581 c, embedded in a broader study of tidal evolution as planetary systems evolve. The study has implications not just for rocky worlds but for planetary formation in many scenarios.

The work of Brian Jackson, Richard Greenberg and Rory Barnes (University of Arizona) draws on a key fact: A planet’s orbit can be greatly affected by tides that the planet raises on its star, and on the tides the star raises on the planet. In fact, tidal distortion and orbital evolution work together, tidal forces producing internal heating at the expense of orbital energy. Thus many close-in planets probably formed further out from their host star than their present position. In a typical case, say the authors, tidal heating increases as a planet moves inward and then decreases when the tides circularize the orbit and shut down the heat mechanism.

But each case will be different, the strength and timing of these effects determining a planet’s properties. The team’s intention is to construct heating histories for planets whose radii have been measured, sometimes with results that vary from theory. And that gets me back to Gl 581 c, for in terms of planets with masses less than ten times Earth’s, such heating could have played a role in the planet’s geophysical development. The Arizona team finds that the contribution of tidal energies on two ‘super Earths’ — Gl 581 c and GJ 876 d — should produce a heat flux with profound implications:

Among terrestrial-scale planets, we find that tidal heating may have dominated the geological and geophysical evolution of the planets and control their current character. The tidal heating rate for GJ 876 d may be orders of magnitude greater than the magnitude considered by Valencia et al. to be geophysically significant. For Gl 581 c tidal heating may yield a surface flux about three times greater than Io’s, suggesting the possibility of major geological activity.

Three times that of Io? Gl 581 c looks less hospitable all the time. The case of GJ 876 d is even more extreme. This ‘super-Earth’ of 5.89 Earth masses hasn’t been in the habitability picture because its two-day orbit keeps it far too close to its star for liquid water to exist. But while the planet has been considered vulnerable to tidal stresses, I don’t think anyone was prepared for what the Arizona team found:

…radiogenic heating of GJ 876 d might have been adequate to initiate plate tectonics, but our results indicate that tidal heating may have been a major contributor to the geological and geophysical character of the planet. Tidal heat has provided an important component of the heat budget for this planet, perhaps the dominant component during at least the past ~108 yr. The tidal heating rate would be so large, in fact, that GJ 876 d is unlikely to be a solid, rocky body.

I’ve only focused on two super-Earths here, but the paper also offers interesting takes on planets like HD 209458 b, whose radius is larger than predicted, and HAT-P-2 b, whose radius is well below prediction. Tidal heating histories may help us understand these apparent anomalies. The paper is Jackson, Greenberg and Barnes, “Tidal Heating of Extra-Solar Planets,” accepted by the Astrophysical Journal (abstract).