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The Ethics of Directed Panspermia

Interstellar flight poses no shortage of ethical questions. How to proceed if an intelligent species is discovered is a classic. If the species is primitive in terms of technology, do we announce ourselves to it, or observe from a distance, following some version of Star Trek’s Prime Directive? One way into such issues is to ask how we would like to be treated ourselves if, say, a Type II civilization – stunningly more powerful than our own – were to show up entering the Solar System.

Even more theoretical, though, is the question of panspermia, and in particular the idea of propagating life by making panspermia a matter of policy. Directed panspermia, as we saw in the last post, is the idea of using technology to spread life deliberately, something that is not currently within our power but can be reasonably extrapolated as one path humans might choose within a century or two. The key question is why we would do this, and on the broadest level, the answer takes in what seems to be an all but universal assumption, that life in itself is good.

Image: Can life be spread by comets? Comet 2I/Borisov is only the second interstellar object known to have passed through our Solar System, but presumably there are vast numbers of such objects moving between the stars. In this image taken by the NASA/ESA Hubble Space Telescope, the comet appears in front of a distant background spiral galaxy (2MASX J10500165-0152029, also known as PGC 32442). The galaxy’s bright central core is smeared in the image because Hubble was tracking the comet. Borisov was approximately 326 million kilometres from Earth in this exposure. Its tail of ejected dust streaks off to the upper right. Credit: ESA/Hubble.

How Common is Life?

Let’s explore how this assumption plays out when weighed against the problems that directed panspermia could trigger. I turn to Christopher McKay, Paul Davies and Simon Worden, whose paper in the just published collection Interstellar Objects in Our Solar System examines the use of interstellar comets to spread life in the cosmos. An entry point into the issue is the fi factor in the Drake Equation, which yields the fraction of planets on which life appears.

We need to know whether life is present in any system to which we might send a probe to seed new life forms – major problems of contamination obviously arise and must be avoided. If we assume a galaxy crowded with life, we would not send such missions. Directed panspermia becomes an issue only when we are dealing with planets devoid of life. To the objection that everything seems to favor life elsewhere because we couldn’t possibly live in the only place in the universe where life exists, the answer must be that we have no understanding of how life began. Abiogenesis remains a mystery and the cosmos may indeed be empty.

We live in the fascinating window of time in which our civilization will begin to get answers on this, particularly as we probe into biomarkers in exoplanet atmospheres and conceivably discover other forms of life in venues like the gas giant moons. But we don’t have such answers yet, and it is sensible to point out, as the authors do, that the Principle of Mediocrity, which suggests that there is nothing special about our Solar System or Earth itself, is a philosophical argument, not one that has been proven by science. We have no idea if there is life elsewhere, even if many of us hope it is there.

Protecting existing life is paramount, and the authors point to the planetary protection issues we face in terraforming Mars, the latter being a local kind of directed panspermia. They cite the basic principle: “…planetary protection would dictate that life forms should not be introduced, either in a directed mode or through random processes, to any planet which already has life.”

I like the way McKay, Davies and Worden present these issues. In particular, assuming we picked out a likely planet in the habitable zone of its star, would there ever be a way to demonstrate that life does not exist on it? The answer is thorny, it being impossible to prove a negative. This gives rise to the possibilities the authors consider when evaluating whether directed panspermia could be used. From the paper:

1. Life might exist on a target planet in low abundance and be snuffed out by seeding.

2. Alien life might be abundant on a planet but present unfamiliar biosignatures yielding a false negative.

3. A comet might successfully seed a barren target planet but go on to contaminate others that already host life, either in the same planetary system or another. The long-term trajectory of a comet is almost impossible to predict.

4. Even if terrestrial life does not directly engage with alien life, it may be more successful in appropriating resources, thus driving indigenous biota to extinction by starvation

There are ways around these issues. Snuffing out life would not be likely if we seeded a protoplanetary disk rather than a fully formed world, which would also remove objection 2, for there would be no biosignatures to be had. A planet that turns out not to be barren might be saved from our seeding efforts by using some kind of ‘kill switch’ that is available to destroy the inoculated life. But all these issues loom large, so large that directed panspermia collapses unless we establish that numerous habitable but lifeless worlds do exist. If life is vanishingly rare, then a kind of galactic altruism can be invoked, seeing our species as gifted with the chance to spread life in the galaxy.

Off on a Comet

All this is dependent on advances in exoplanet characterization and research into life’s origins on Earth, but the questions are worth asking because we may, relatively soon as civilizations go, begin to learn tentative answers. It seems natural that the authors would turn to interstellar comets as a delivery vehicle of choice. Here’s a passage from the paper, examining how spores from a directed panspermia effort could be spread through passing comets by the injection of a biological inoculum into comets whose trajectories are hyperbolic or could otherwise be modified. Such objects need not impact another planet but could be effective simply passing through their stellar system:

These small particles are subsequently shed as the comet passes through systems that have, or will form into, suitable planets, such as protostellar molecular clouds, planet-forming nebulae around stars, and recently formed planetary systems. The comets themselves are unlikely to be gravitationally captured or collide as they move through star systems… but the small dust particles released by the comet—as observed in 2I/Borisov—will be captured. Particles measuring a few 10s to 100s microns in radius are large enough to hold many microorganisms but small enough to enter a planetary atmosphere without significant heating.

Image: This artist’s impression shows the first interstellar object discovered in the Solar System, `Oumuamua. Note the outgassing the artist inserts into the image as a subtle cloud being ejected from the side of the object facing the Sun. Credit: ESA/Hubble, NASA, ESO, M. Kornmesser.

The focus on comets is natural in the era of ‘Oumuamua and 2I/Borisov, and the expectation is widespread that we will be learning of interstellar objects in huge numbers moving through the Solar System as we expand our observing efforts. Why not hitch a ride? There is every expectation that the inoculum injected into a comet could survive the journey, to one day settle into a planetary atmosphere. Thus:

One meter of ice reduces the radiation dose by about five orders of magnitude… In a water-rich interstellar comet, internal radiation from long-lived radioactive elements (U, Th, K) would be expected to be less than crustal levels on the Earth. In such an environment, known terrestrial organisms might remain viable for tens to hundreds of millions of years. We can also take into account advances in gene editing and related technologies that might enable psychrophiles, which are able to very slowly metabolize and repair genetic damage at temperatures as low as-40°C…, to ‘‘tick over,” although slowly, at still lower temperatures. That would enable them to remain viable for even longer durations.

The time scales for delivering an inoculum to an exoplanet are mind-boggling, on the order of 105 to 106 years just to pass near another stellar system. The authors point out that given the hyperbolic velocity of 2I/Borisov, it would take the comet approximately 40,000 years to travel the distance to Alpha Centauri, and 500 million years to travel the distance of the Milky Way’s radius. Indeed, the most likely previous encounter of ‘Oumuamua with another star occurred 1 million years ago.

Perhaps orbital interventions when seeding the comet could alter its trajectory toward specific stars, to avoid the random nature of the seeding program. And I think they would be necessary: Random trajectories might well take our comet into stellar systems with living worlds that we know nothing about. Thus the authors’ point #3 above.

The Rhythms of Panspermia

Clearly, directed panspermia by interstellar comet is for the patient at heart. And as far as I can see, it’s also something a civilization would do completely out of philosophical or altruistic motives, for there is no conceivable return from mounting such an effort beyond the satisfaction of having done it. I often address questions of value that extend beyond individual lifetimes, but here we are talking about not just individual but civilizational lifetimes. Is there anything in human culture that suggests an adherence to this kind of ultra long-range altruism? It’s a question I continue to mull over on my walks. I’d also appreciate pointers to science fiction treatments of this question.

There is an interesting candidate for directed panspermia close to the Sun: Epsilon Eridani. Here we have a youthful system, thought to be less than a billion years old, with two debris belts and two planets thus far discovered, one a gas giant, the other a sub-Neptune. If there is a terrestrial-class world in the habitable zone here, it would be a potential target for a life-bearing mission. So too might a Titan-class world, which raises the interesting question of whether different types of habitability should be considered. We may well find exotic life not just on Titan but also under the ice of Europa, giving us three starkly different possibilities. Would a directed panspermia effort be restricted to terrestrial class worlds like Earth?

Whatever our ethical concerns may be, directed panspermia is technologically feasible for a civilization advanced enough to manipulate comets, and thus we come back to the possibility, discussed decades ago by Francis Crick and Leslie Orgel, that our own Solar System may have been seeded for life by another civilization. If this is true, we might find evidence of complex biological materials in comet dust. We would also, as the authors point out, expect life to be phylogenetically related throughout the Solar System, whether under Europan ice or on the surface of Mars or indeed Earth.

Always complicating such discussions is the possibility of natural panspermia establishing life widely through ejecta from early impacts, so we are in complex chains of causation here. We’re also in the dense thicket of human ethics and aspiration. Let’s assume, as the authors do, that directed panspermia is out for any world that already has life. But if life is truly rare, would humanity have the sense of obligation to embark on a program whose results would never be visible to its creators? We cherish life, but where do we find the imperative to spread it into a barren cosmos?

I’ll close with a lengthy passage from Olaf Stapledon, a frequent touchstone of mine, who discussed “the forlorn task of disseminating among the stars the seeds of a new humanity” in Last and First Men (1930):

For this purpose we shall make use of the pressure of radiation from the sun, and chiefly the extravagantly potent radiation that will later be available. We are hoping to devise extremely minute electro-magnetic “wave-systems,” akin to normal protons and electrons, which will be individually capable of sailing forward upon the hurricane of solar radiation at a speed not wholly incomparable with the speed of light itself. This is a difficult task. But, further, these units must be so cunningly inter-related that, in favourable conditions, they may tend to combine to form spores of life, and to develop, not indeed into human beings, but into lowly organisms with a definite evolutionary bias toward the essentials of human nature. These objects we shall project from beyond our atmosphere in immense quantities at certain points of our planet’s orbit, so that solar radiation may carry them toward the most promising regions of the galaxy. The chance that any of them will survive to reach their destination is small, and still smaller the chance that any of them will find a suitable environment. But if any of this human seed should fall upon good ground, it will embark, we hope, upon a somewhat rapid biological evolution, and produce in due season whatever complex organic forms are possible in its environment. It will have a very real physiological bias toward the evolution of intelligence. Indeed it will have a much greater bias in that direction than occurred on the Earth in those sub-vital atomic groupings from which terrestrial life eventually sprang.

The paper is McKay, Davies & Worden, “Directed Panspermia Using Interstellar Comets,” Astrobiology Vol. 22 No. 12 (6 December 2022), 1443-1451. Full text.

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{ 54 comments… add one }
  • Stephen Lang December 16, 2022, 13:46

    There was an episode of Star Trek The Next Generation called “The Seeeders” that was about Directed Panspermia. In that episode, they found fossilized DNA that was billions of years old that contained a code that led them to a Dead Planet and then the fossilized DNA was placed into a medical tricorder and activated a program that made a holographic projection of the intelligent Species who “seeded” several planets along with an audio message.

  • Alex Tolley December 16, 2022, 14:40

    I am going to take a Devil’s Advocate position on our diffidence to directed panspermia and the invocation of a “Prime Directive”.

    The idea of non-interference is a result of our European post-colonial guilt of what we did to indigenous cultures. The Spanish missionaries spread catholicism at the point of a sword, the extraction of precious metals using local slaves. The horrors of the last and greatest colonialists, the British, have mostly been expunged from the British mindset and is only now being appreciated. The genocide of indigenous Americans to make way for the European White Christian culture seems often regarded as a successful creation of a new omelet made with a regrettably few broken eggs. Bradbury’s “The Martian Chronicles” is an allegory of the American expansion, but where the indigenous Martians died out not with violence, but conveniently simply by the presence of the colonists.

    Clearly, our regrets over colonialism are a modern sentiment and certainly not one shared by previous civilizations. Genocide and mass slavery were common, even suggested as “God’s will” in religious texts. But in the regrets of the few, do we really not prefer the results of the Roman civilizing of the world, or the European civilizing later? If Europe, led by the USA, as a technological civilization is to colonize space and the galaxy, could this be achieved in an alternate history where the Americas were not colonized and the indigenous cultures allowed to continue uncontaminated? Our culture has created new ideas and artifacts that we cannot deny have improved the lives of individuals. We live in a post-Malthusian world, and while we are far from creating a utopia, we are surely Slouching Towards Utopia.

    In summary, brutal as it may be, colonization by Europeans has had a net benefit in humanity’s “manifest destiny” to colonize space.

    But what about life? In Star Trek II: The Wrath of Khan, the use of the Genesis Device was predicated on the idea that existing life was not be harmed. In teh parlance of the script, Dr. Carol Marcus states that there must not be even a particle of pre-animate matter on Alpha Ceti 6 or the experiment is canceled. As McCoy later confirms, the GD can destroy existing life and replace it with its own matrix. This is the “Prime directive” taken to its logical conclusion.

    But is it a flawed policy? Darwinian evolution is a natural mechanism that replaces the “less fit” with the “fitter”. That has resulted in the wonderful history of life on Earth. Like it or not, some magnificent species have come and gone. Humanity is speeding up this process in the Anthropocene. It is this Darwinian evolution by natural selection that was taken as an analogy by the eugenics movement to usher in some unnatural selection and justify the history of European colonization of the “less fit” indigenous species, as well as the weaker members of the European culture. The horrors of Nazism were the result, and as Hitler noted, the creation of an Aryan superman race was based on the American experience. Today the eugenics movement has morphed into the idea that the wealthy are the fittest (and smartest) and the poor that they help to create should die by their own devices. History seems to have taught us little in this regard. But humanity, as a whole, has done much the same to the planet. Ecosystems are ravaged, species are driven to extinction, and where the mass of animals on the planet is now 98% human and domesticated animals. There is clearly a loss here, but on the plus side, the number of human minds has increased to 8 billion-plus, the global economy is at an all-time high, and we contemplate it getting much larger to support our spacefaring future.

    If we accept natural evolution will replace species, even whole groups of organisms, and that as Clarke suggests, that mind is the most precious thing in the universe, then isn’t it our duty, as the “old ones” did, to farm teh galaxy to enhance the creation of mind, and “sadly weed out” the failures? One can see the religious analogy with the Catholic missionaries, but is the argument wrong? I don’t believe so.

    The last thread before justifying directed panspermia that might change existing planetary biospheres is this. If comets are a natural mechanism to harness panspermia, isn’t it likely that it was already naturally doing the same process? If so, the same effect was occurring – biospheres were changed as the fitter life was introduced naturally and replaced the extant life. If the introduced life was less fit, it would fail, but at the same time, the comet might well sweep up this fitter life in the system and this life would become the new dominant form. IOW, comets became the mechanism to harness Darwinian evolution in the galaxy and beyond.

    If this last is true, then why worry about preserving a “less fit” life? We should be sending both procaryote and eucaryote life everywhere and if it successfully colonizes a living planet, then this means we have achieved useful unnatural selection that will eventually bring forth new minds, rather than be stuff at pre-mind life.

    In practical terms, we know that procaryotes were the only forms of life on Earth for perhaps 2 billion years or more. It took the evolution of eucaryotes to achieve complex life and mind. Directed panspermia can short circuit that transition on multitudes of planets still in the procaryote-only stage. And worlds that have eucaryote life will either prove fitter than terrestrial life and remain uncolonized or will be replaced.

    In summary, we need not be overly concerned about destroying extant life by introducing our own. The fittest survive, and that is a good algorithm to increase mind and all that entails for the future of life in the universe.

    • Project Studio December 17, 2022, 2:42

      Quite a lot to unpack there. For one, the notion that evolution leads to a ‘fitness’ that inevitably leads to the development of mind. In our universe, environments change chaotically and what is fit to survive at one moment is unfit at another. Western technology’s colonization of space and the galaxy is far from a fait accompli, and we may find the fourth industrial revolution leads to a dark age dystopia instead of a trans human expansion across the solar system. The old ones of our indigenous cultures have long laid claim the ability to navigate a multiverse that western science only dimly senses as an abstraction. After all, who were the first to discover the companion white dwarf Sirius B? Who will be waiting for us when we arrive there?

      • Alex Tolley December 17, 2022, 14:44

        (…) notion that evolution leads to a ‘fitness’ that inevitably leads to the development of mind.

        We only have one example, terrestrial evolution. There is a clear increase in relative brain size to body mass indicating that brains are a fitness enhancer on Earth. With brains comes mind. Now Clarke may have wanted the mind to be ever-improving with technology to accompany it, but the mind does appear to come with brains. [Consciousness is another matter.]

        There is certainly no guarantee that humanity continues to advance technologically and colonize space. Just as ancient civilizations collapsed, so might our current global civilization. I would hope that this isn’t something intrinsic to intelligence, or to our particular form of intelligence so that we can manage our future.

        As for The Sirius Mystery… :-D

        • Project Studio December 20, 2022, 21:13

          We’re learning that there are many different types of intelligence. The western analytic mind, lost in abstraction and reduction, lost the capacity for inductive and holistic intelligence. While the term ’emotional intelligence’ can be a bit vague, the ind of intelligence which gets us out of our own skin and lets us see things, and ourselves, from a point of view other than our own is essential to the objectivity that western science claims but consistently fails to live up to (confirmation bias). Looking in to appreciating the subjective nature of every experience as well as the relative double-slit impossibility of seeing from a single objective vantage point in any humanly meaningful frame of reference is not in the tradition of western science, but needs help from eastern philosophical references to begin building a corresponding mind. Of course this came from two of many cultures that were oppressed by western colonization and gunboat diplomacy. We needn’t double-down on repeating the same methods in the vain hope of achieving different results.

          An sci-pulp fiction TV series a few years back promoted an alternative vision of future human evolution, somewhat akin to that of HG Wells, where speed, viciousness, and herd coordination prove more fit than intelligence. Meet the ‘Abby’ (aberration) from Wayward Pines:
          https://www.imdb.com/title/tt2618986/

    • Jer December 17, 2022, 13:29

      Though I enjoy the Philosophy of Ethics as much as the next skywatcher, it is a navel-gazing exercise at best (and I certainly disagree with all past ‘guilt’ associations). As with most things, the devil is in the details. Our approach to any conundrum, be it the experimentation on animals or the introduction of basic income or capital punishment can only be realized by gathering the detailed data and engaging the best analysis at that time, which could even be the current monetary value of a human life (known and never infinite). As with any profession, especially those governed by ethics councils serving the public, such as engineering, medical, law, etc., ask only that, for the most part, we act reasonably. We act as it would be expected of a knowledgeable, experienced, and competent ‘reasonable’ professional practitioner of that art. We need not be perfect, infallible, or prescient. We need only use the current state of technology, understanding, and risk assessment; thus reporting it precisely and comprehensively. Divergence of solutions is not an excuse. This is common and the field is mature. Several academic papers are available. Whether the public can be swayed by such ‘rational’ conclusions is, of course, another matter, hence, perhaps, private enterprise. The bottom line is that observations will improve, theories will solidify, options will increase; we needn’t be burdened by commitments beyond our expertise or past actions; this too is data.
      That all being said: it would be interesting to see a précis of all known academic indicators of exo-life and current ideas of engaging such environments.

      • Alex Tolley December 17, 2022, 21:32

        One of the benefits of “guilt” for past actions has been Germany’s strong adherence to preventing a resurgence of nazism. There are nazis in Germany, particularly in the East, but the government takes active measures to suppress it. In contrast, Britain has conveniently forgotten about its support of slavery and its more brutal colonialism, and the US allows active suppression and whitewashed history to quell any suggestion of guilt over the genocide of the native population as well as a Southern economy once based on slavery. At least California is thinking seriously about reparations for slavery. It is a start, although I expect a lot of pushback.

        • Robert December 19, 2022, 13:37

          I personally benefited from German reparations over the Holocaust. I think some form of reparations over slavery should be at least debated. My idea is college or some equivalent education.

          Even so, I’m not sure suppression of political ideas is the right path. That could ultimately lead to a backlash and resurgence. As could the gradual erosion of free speech and ideas in Western societies.

          • Michael December 23, 2022, 9:15

            Why don’t you ask the Romans as well or their descendants for a few quid while you’re at it or the Arabs who sold the slaves. Perhaps you should also have a good look at what the liberalwashing left have done on the social media sites, twitter is one of many I bet. IMO we should stick to space and technology discussions rather than ‘apologism’ as that is reason I like this site so well, little to no politics.

            We can’t change the past but we can learn from it.

      • Jer December 18, 2022, 11:25

        Though essential to have a good working methodology or approach to assessing targets, perhaps also having a compelling and rational value system to inform conclusions may help. For better or worse, the Earth is using economic valuations, though some items are certainly ‘externalities’ as the verbiage goes, but numbers are assigned just the same and do have a certain equilibrium that indicates rareness, sentimentality, and academic interest ‘well over’ the re-sell cost of its parts – such as great art or great ‘natural’ location.
        As some may have intended in this comment section, I propose Complexity. Often suggested, but typically ill-defined, it could encompass sentience or even intelligence of the One, a grouping or community, an eco-system, or a service life, or a cluster of essential components with limited interaction but critical combination. The calculations would not be straight-forward: is the presence of the human brain more ‘complex’ valuable than 100 square miles of dense jungle eco-system? is the presence of a lake filled with the only water serving thousands of local animals more ‘complex’ valuable than the semi-conductor plant, with cooling needs, providing electronics for many computers, cars, and phones? It might be thought that such a calculation may have a series of terms that resemble the Fermi Surmise/ Question.
        In any event, an excellent example of a methodology for assessing intervention of a unique environment can be found through Fish and Wildlife, via ESA at:
        https://www.federalregister.gov/public-inspection/2022-27225/endangered-and-threatened-species-tiehms-buckwheat

        • Ron S. December 18, 2022, 14:39

          Don’t play that game. It is possible to promote both the environment and the economy. It is vested interests that game the system to maximize profit in the shortest possible time and with minimum financial risk to themselves. Since environmental degradation is often an obstacle on that path it is declared expendable. “Do you want jobs or trees!?”

          • Henry Cordova December 18, 2022, 23:55

            One of my proudest possessions is a copy of the following cartoon, signed by the artist.

            https://pbs.twimg.com/media/CdnGXpDUUAAW2MB.jpg

            Those who who have the audacity to ask “Do you want jobs or trees!?” are the same kind of people who prefer to do their fishing with dynamite.

        • Harold Shaw December 18, 2022, 15:44

          Which is more complex, (1 x 10) or (1+2+3+4)? Both achieve the same value that can be used as a metaphor for total system complexity. I would answer the second set is more complex.

          I don’t see a way to build an observation based, relativistic ethics system without using the health of independent observers as an anchoring value. Allow an ocean ruled by an old world god to represent the universe, and this anchor insists on a boat built of diversity. Eating some of our fellow passengers aboard this ship can’t be observed as sinful. Willfully eating everyone on board and causing the boat to sink must be sinful. Eating everything for the sake of building a boat of just one people sounds sinful to me as well.

        • Mike Serfas December 19, 2022, 16:30

          I think an accurate metric for complexity would be a useful theoretical advance in understanding life. To my mind, life is fundamentally homeostasis, and homeostasis might somehow be defined in terms of the number of inputs and the degree of feedback they create. I’m not sure exactly how to define this – life requires occasional positive feedback for a change of state (as with hemostasis or childbirth) as well as frequent negative feedback. But I think that we might sense that even a house with a thermostat, fuse box, and alarm is more “alive” (albeit to a very small degree!) than one that fails to respond to its environment at all, and by extension an organism that responds to everything from ammonia vapors to thorns, with a far richer internal allosteric regulation of its biochemistry, is correspondingly more alive.

          Even so, I don’t think this is related to consciousness, which seems inherently and limitlessly disruptive and so far in our case has proven itself uniquely capable at destroying planetary homeostasis. Consciousness drives people to die for mountaintop climbs and holy wars and such at least as often as it helps to restore a balance.

    • gbaikie December 19, 2022, 3:14

      “In summary, we need not be overly concerned about destroying extant life by introducing our own. The fittest survive, and that is a good algorithm to increase mind and all that entails for the future of life in the universe.”

      My problem is not destroying life, but our life adding something from it that kills us.
      I would add life to Mars, and see if any life there changes, and if does, may sure it doesn’t kill us. Or with Mars one could contain/isolate it, and/or abandon Mars and don’t come back.
      Or what could safe about alien life is it completely different- very alien, but our life [roughly speaking, microorganisms] “marrying and having children with other life”- could be lethal to us. Or transform us.
      Though different environments [without any kind of alien life] could also alter our life.

  • Alex Tolley December 16, 2022, 16:09

    Long-range altruism in SciFi

    Movies:

    “Mission to Mars” The ending suggests that the Martians seeded Earth with life and then they left the solar system.

    “Prometheus” The prologue suggests that the “engineers” seeded barren worlds with life. It is not clear if that was long-range altruism or not.

    “2001: A Space Odyssey” (and novel). The program to seed mind by introducing memetic parasites into animals with primitive minds was a a long-range program. During the program, biological aliens changed to machines and then to non-corporeal beings.

    In a similar vein – “A for Andromeda” has [machine] aliens transfer their schemes via radio transmissions that parasitize the technological species’ technology to convert planets. It seems long-range as the machines are sedentary in their home world. Altruism or an alien attack?

    In the real world, the philosophy of “Effective Altruism” is technically about long-range altruism, although I am appalled at its methods and “the ends justifies the means” goals.

    Philosophically, it is difficult to determine true altruism. Human altruism is often hiding benefits for the individual (or their genes). Therefore is directed panspermia truly altruism in that mature biospheres may emerge long after the seeders have gone extinct or is it just a means to “selfishly” spread terrestrial life processes? One can argue that any preservation of our knowledge and culture is really a means to project our culture into the future after we have disappeared, rather than letting other cultures emerge without our “help”.

    I admit that I want our Enlightenment Culture to survive beyond the survival or dominance of European culture, even biological human civilization.

  • Michael Fidler December 16, 2022, 16:39

    We are forgetting the giant melting pot Jupiter. The nearest place that has all the ingredients and temperatures for life. There we may find the answers to the question of external panspermia. Before making a mess of the universe we should look for clues in our own solar system and Jupiter has the central pivot when it comes to comets. It therefore acts as a natural chamber for any panspermia entering the solar system. What we find there may tell us what we need to understand before we make an irreversible mistake.

  • Mike Serfas December 16, 2022, 17:01

    What strikes me about this discussion and the paper is how remote and faraway it all sounds, though the most relevant decision, and the starting point for all others, lies almost immediately at hand. Within a few years, China and the U.S. are likely to establish bases on the Moon, which hypothetically is subject to planetary protection. It seems inevitable that leaky sewage systems, unfortunate astronauts alas, and hopefully (?) some interesting science experiments will lead to the “contamination” of the lunar landscape. We may also see some science done that can detect whether there are niches for life deep in the Lunar crust, and whether they have been occupied by prior Earthly panspermia, shared indigenous lifeforms from before the Theian collision, or unique Lunar evolution. I suspect the experiences of the Moon will put more shape to this conversation, yet the circumstances around them are being established now.

  • Afterthought December 17, 2022, 1:28

    What gives you the right to kill a plant and eat it?

    By the same right we will spread life to the galaxies.

  • orion elenzil December 17, 2022, 2:03

    An additional twist in reasoning about the ethics of panspermia is a possible urgency.

    Here’s how I think about it:

    1) a universe with life is more beautiful than one without. this is indefensible, you buy it or you don’t.

    2) it’s not at all clear that there’s life outside the solar system, or even off earth.

    3) if humanity snuffs itself out, there’s no guarantee that another space-faring civilization/species will develop here.

    if you buy these three, then in my opinion panspermia starts to look like an imperative.

    • Alex Tolley December 17, 2022, 21:21

      Let’s rephrase this using colonialist policies:

      1. Places with white Europeans and their culture is more beautiful than those places without them. You buy it or you don’t.

      2. It is not certain this culture exists everywhere, even anywhere beyond the shores of Europe.

      3. White Europeans and their culture snuff themself out, there’s no guarantee that another culture with the same racial traits and culture will arrive and colonize the empty continent of Europe.

      Panspermia needs to be controlled so that whatever the level of “non-intervention” is agreed, that panspermia obeys those instructions. It is not unlike the idea that genetic engineering, especially with pathogens, is maintained in biohazard containment facilities so that we don’t accidently cause massive problems for the global population.

      • orion elenzil December 20, 2022, 2:55

        thanks for the reply.

        this was fun, I feel like we had a real exchange of ideas.

  • Michael December 17, 2022, 6:38

    I would prefer robotic exploration of ‘organic life’ systems and human of ‘sterile of life’ systems. Then we are not imposing our ‘baggage’ on their systems.

  • Trevor Cramphorn December 17, 2022, 9:49

    “the answer takes in what seems to be an all but universal assumption, that life in itself is good.” Not entirely universal. The philosophy of antinatalism suggests that life leads to suffering and that it would be better for life not to exist. (I don’t necessarily subscribe to this.)

    We should also remember that “survival of the fittest” is often “survival of the firstest”. The organism that first occupies a niche will tend to block out other organisms even though they might have greater evolutionary potential. Seeding an unpopulated world or a planetary disc might prevent the later development of “better” organisms.

    • Alex Tolley December 17, 2022, 21:12

      We should also remember that “survival of the fittest” is often “survival of the firstest”. The organism that first occupies a niche will tend to block out other organisms even though they might have greater evolutionary potential.

      Do you have a reference for this assertion?

      • Trevor Crampnorn December 19, 2022, 7:48

        The best example is dinosaurs developing into solely bipedal predators and mammals into solely quadrupedal predators. In the first care the earliest dinosaurs and earliest mammals were coexisting. Regular evolutionary pressures led to dinosaurs filling the larger animal niches with the first dinosaurian predator being bipedal. This led to all subsequent predatory dinosaurs being bipedal – no exceptions. Come the K/T mass extinction and the dice are rolled again. Mammal too over the large animal niches and all mammalian predators are quadrupedal, again, no exceptions. Interestingly, crocodiles began to develop towards being specialist non – aquatic predators, but they could not compete with endothermic mammals. Equally, avian dinosaurs developed into flightless bipedal predatory birds but with no teeth, lightweight bones and largely useless wings instead of arms they were quickly out competed.

        The overall mechanics of predation have remained more or less constant so why have two different solutions developed? It seems to be down to who gets in first. A pack of velociraptors dropped onto today’s African savannah would likely get on very well, but there is no way for any existing species to evolve in this direction as every intermediate niche has already been filled by animals which have had time to fully adapt.

        Getting back to guided panspermia, my point is that by introducing DNA carbon based life into something like a protoplanetary disc, we could prevent something vey different and possibly better adapted from evolving naturally.

      • Mike Serfas December 19, 2022, 17:26

        I love that phrase “survival of the firstest” … whether it is true or not is another issue. In the context of the Fermi paradox we sometimes have these conversations about whether the K-T mass extinction was actually necessary for an intelligent species to arise on Earth; of course, nobody really knows. An interesting argument for both sides can be found with the Great American Interchange: when Panama became an isthmus, the life forms of North and South America were able to move back and forth freely. What it tells us is that first off, the presence of placental mammals before the interchange did not doom marsupials, so perhaps they were “firstest” … yet the access of North American placentals proved devastating nonetheless. There are aspects of this that I don’t understand — for example, Thylacosmilus – the *marsupial* saber-toothed tiger* – was driven extinct during the Interchange, but it may never have directly competed with Smilodon. Evolution is a complex series of mysterious disasters and sudden opportunities, so I’m not sure we can say a statement like this is even “mostly” true or false … even before we put alien life into the mix.

        One aspect that could use more investigation is whether there are (by analogy to cells) “stem species” that give rise to many others, versus “differentiated species” with a lower potential for further evolution. For example, birds frequently lose their ability to fly after colonizing an island, but the flightless birds are unlikely to go much further. In the extreme case, there are asexual lizard species, nearly all of recent origin – the ability of every animal to procreate gives them an immediate advantage, but over hundreds of thousands of years the lack of sexual recombination dooms them. In the case of panspermia, we should critically evaluate whether tardigrades really have the ability to give rise to new phyla, or whether they will simply use up resources that might have gone to evolve a more versatile native life form.

        * It’s more proper to call Smilodon a saber-toothed cat because it’s not a tiger, but Thylacosmilus isn’t a cat either. :)

  • Javier Garcia December 17, 2022, 17:33

    Probably the biggest damage the WWII brought is the replacement of certain paradigms.

    As a secondary effect of the rejection of the nazi phylosophy, we have now an over protection over minoritary cultures and enviroment that in fact stops industrial and economic depelopment.

    Also a contribution to this is the guilty feeling some Europeans and North Americans have due to Colonialism.

    Fortunately those ethics are not present in China and other one time poor countries, and consequently they will take the lead if we are fool enough to step aside.

    As members of the human race, we have a priviledged position to secure the continuation of our species by spreading into Cosmos. Not doing it due to ethics can only lead to our extintion sooner or later.

    We can be hit by a planet killer rock, we can die in our own enviromental problems, pandemics, or absurd wars. We will meet a more advanced civilization that will easily eliminate us without regret since we are confined to this planet, etc.

    Expansion into Cosmos and its long term version, panspermia, is a must in my opinion. As it happened many times before in the past, for example during the middle age, the sooner we get rid of unsane ethics, the sooner we will accomplish our destiny and secure our future.

    Cosmos is big enough to sustain many wonderful forms of life to protect and at the same time allow our expansion.

    In my view, the only reason for apparently being “alone” is that we have born in a corner of the galaxy which size is enormous given the limitation of travel speed by the speed of light.

    We have born in a farm many thousands of miles away from the nearest city and the travel speed is the speed of a horse. But without doubt, sooner or later, a motor civilization will arrive at our farm, and human civilization at Earth will come to an end, no matter if visitants have good intentions or not.

    Where our biological paterns will be by then?

    • Alex Tolley December 17, 2022, 21:10

      So genocide is an acceptable solution for the strong over the weak? Is China’s action regarding the Uighurs an acceptable policy? So much for moral philosophy. You seem to want to throw all these ideas away in favor of the “Law of the Jungle”. This seems like a sure way for humans to self-extinguish.

      • Javier Garcia December 18, 2022, 15:09

        If we protect nature against its natural fight and mutation we are doing something that is non natural, we prevent the natural cycles of extinctions, we prevent new species from appear, etc…

        We can not play angels or devils, we need to walk our own way, avoiding damage when possible, accepting always the responsibility of being the leader species of the planet and not hesitating to step on the grass just because grass can be damaged.

        We must be wise enough to know when a limited damage can be the door to a future benefit/progress.

        With the presently stablished way of over protective thinking we had never exit the caves. We had never reached the Moon. We will decae until our grandchildren will be taught that the man walk in the moon was a fake. That is the best way to a new dark age like the post Roman Empire Millenium.

        • Gary Wilson December 20, 2022, 17:40

          I don’t think you have to worry about humans preventing the “natural cycles of extinctions” Javier. Humans are busy causing the sixth mass extinction with our deeply flawed behaviors centering around individual greed. We will be responsible for the extinction of hundreds of thousands of species and it won’t be beneficial to anyone or anything at all. We are undermining our own natural ecosystems which support our existence. Your argument is confusing and unfocused. Please try again.

    • Harold Shaw December 18, 2022, 22:39

      The position that a lasting negative effect of ww2 is our reluctance to erase people is one of the positions.

      Nazi Germany and the CCP use emotional binging on people as a way to define themselves. This is not the equivalent of competing over sustenance or vigor.

      Zoom in to the level of the individual and we can see zero sum competition, zoom out to the level of the ecosystem and we see non-zero sum competition. An intelligent agent able to perceive the functioning of ecosystems insisting that zero sum competition is dominant is the equivalent of a transmission claiming they are the dominant description of a car.

      • Javier Garcia December 19, 2022, 8:08

        Nazis could have claimed that they came from Mars. Propaganda has little effect on the long term.

        Reluctance to erase people has always been there. Not a product of WWII. We are a social species. In general we try not to kill. That is not the problem.

        The problem is when feeling guilty because western culture is technological advanced and we try to “protect” other cultures to the point of slowing down our own development.

        Is like when they say in an airplane that first to help somebody with his oxigen mask you must fit yours first.

        We have forgotten/postpone our stellar dreams in favor of other goals involving protecting environment and other cultures from changing. And as ethic as it might appear to be, Europeans are leading these effort where Rusia, China or even sometimes the USA is reluctant to be the example to follow. Why? Because we feel guilty for being the leading civilization for centuries, pushing other countries to severe destruction?

        I am confident there is a way those cultures help themselves grow without our parental help.

    • Mike Serfas December 21, 2022, 15:33

      I fear this has side-tracked too far into politics, but from a U.S. perspective it looks like protection for minorities was vital to industrial and economic development. Desegregation of the South, which was direly poor in the 1960s, led to decades of strong economic progress, to the point where it now competes successfully with the North for major projects.

      To strike out in the general direction of our topic, I have to admit that no matter how ridiculous it may seem to protect the environment of airless worlds while our own is falling apart, it remains conceivable that there are xenobiological treasure troves out there that can catalyze reactions we never even think about doing on Earth, and that “planetary protection” ethics really will bring tangible economic rewards by preserving them from destruction by a terraformed environment. This is analogous to pursuing eco-tourism rather than clear-cutting forests. It should be clear, barring some cataclysm of disease, that the accumulated evolutionary “know-how” of two geneses of life would have more long-term potential than that of one. The big question is how long we can reasonably consider this to be a possibility in desolate places like the Moon.

  • Robin Datta December 18, 2022, 9:38

    Ethics begins with the molecular machinery in the primordial soup. For anything suggestive of “life” to emerge from that soup, that life must incorporate in its system the imperative of survival, a sine qua non. In the long term, survival would need to include the imperatives of growth and replication. And these may crowd out its cousins. That’s why only Homo sapiens from the half dozen or so former Homo(es) is still around. That motive force also caused many indigenous tribes of the Americas to disappear. And the passenger pigeon. And at an earlier era, six species of New World elephants including the mammoth, and others such as the giant armadillo, etc.

    Alternate or variant nucleotides, nucleotide sequences and variant aminoacids, chiralities, etc. may be better adapted to differing circumstances. It may be more difficult than uploading oneself into a computer, but transitioning to a different or alien biology may not be impossible.

    More recently, in germanic vs. slavic competition, lebensraum almost prevailed. Sprinkling spores in sundry stellar systems is sadly short of seeding sentience. Planting a forest with a continuous canopy, and encouraging the denizens to brachiate, such that they develop overlapping fields of vision, with depth perception (critical to judging how far off the next branch is), three axes of movement in the shoulders, prehensile hands with a strorg pinch: this could be a rather big order. To be preceded by an effective gas-exchange mechanism for oxygenation, an effectie transport for the oxygen in the form of hemoglobin, a circulatory system to get it to remote parts, a reduction of viscosity by enclosing the hemoglobin in red cells – quite an accomplishment. Taking the other road at the fork, and we have all those phyla and as we get close to us, classes, orders, etc., and indeed a whole horde of primates.

    As the story goes, but for a big rock from the sky, those of us who suckle our young would still be srcambling around in the undergrowth or crawling around on tree branches.

  • Harold Shaw December 18, 2022, 14:57

    The “Mediocrity principle” is scientific and can be demonstrated. A randomly chosen data point has a greater chase of being drawn from the main body of the distribution curve describing its data set. However, self-selection can not be considered a random choice; with SETI, we can’t satisfy the conditions needed to use the principle. Further, the principle remains valid even when Life or space faring intelligence is rare. A data point randomly chosen from a data set of one or few will always be from the middle of the set. The only tool I can think of, that expands the size of the data set is Occam’s Razor, the simpler the mechanism for Life and space faring intelligence, the more of each.

    I have moved into Paul Davies camp, abiogenesis is rare and reveals something about the deep nature of reality. When I view Life through the lens of the uncanny effectiveness of math, I see a mechanical computer running a program that defines a reference frame and a virtual coordinate. Life would be easy to define if it didn’t create an agent, a self. The evolution of complex consciousness is easy to accept if we assume calculating self is the root of Life.

    Directed panspermia via comets looks like the least effect way possible to spread Life through the galaxy and the most likely to destroy independent abiogenesis.

    I think we can make the argument that spreading Life, consciousness and intelligence to where none exists is morally good. However, all evidences predicts that each is a spectrum and increasing the moral good would be achieved by increasing the spectrum.

  • Javier Garcia December 18, 2022, 15:21

    That is how natura works and we should be doing nothing to stop the natural process. Why this world or any other one, should accommodate our naked monkey ethics? We are only one million year here.

    If we take the lead, be it in line with keep after beauty and diversity, and multiply it with new species, be it in line with walk our way into the stars. Not in line with prevent change and progress.

    • ljk December 19, 2022, 16:19

      Then just be ready to accept the possibility that other species may feel the same way about being the dominant chosen ones to spread their genes or equivalent across the Cosmos at all costs.

      Maybe the Universe is more Star Wars than Star Trek, though the latter certainly has its own share of hostile ETI.

  • Robin Datta December 19, 2022, 1:25
    • Alex Tolley December 19, 2022, 15:13

      Excellent lecture. I was particularly interested in his argument “3. Early Start” which was new to me as a rebuttal to the way I have always thought of the early start of life on earth argument as indicative of life being common where conditions are conducive to abiogenesis.

      [His argument is that because our intelligence has arrived near the end of Earth’s habitability for complex life, early abiogenesis was a requirement for our being able to observe it. Hence it is an artifact of our situation, not an independent data point about abiogenesis in general.]

      His final point about being agnostic (“I don’t know”) is perfect and one I endorse as we wait for data on biosignatures (hopefully with a result in my lifetime).

      • Harold Shaw December 20, 2022, 9:22

        Kipping’s argument that an early start is just an artifact of our perspective is the same philosophical argument that we can’t know anything because everything we experience is filtered through our brain, our perspective. We can make that argument, but I don’t see why it is has anything significant to say about SETI. It has more to say about how willing people are to jump to extremely complex and un-scientific answers to the Fermi Question.

        We don’t need an early start to argue that abiogenesis occurs wherever conditions are right. That claim emerges from the assumption that abiogenesis is a material phenomenon. Contrary to Kipping’s claim, an early start increases the chance that intelligence evolves because we have evidence that mechanisms for resetting evolution are distributed throughout the universe. The earlier abiogenesis occurs, the more time evolution has to recover.

        Imo, there is a problem with how many use the early start of abiogenesis. It is used as evidence that abiogenesis is vigorous enough to survive the harsh primordial conditions. The assumption here is that early Earth wasn’t ideal. Imo, it is better evidence that harsh primordial conditions are required.

      • ljk December 20, 2022, 12:00

        How interesting would we really be to an advanced ETI, outside of being one more data point to their Galactic Catalog? Unless intelligent life really is rare.

        https://www.space.com/fermi-paradox-aliens-contact-earth-not-interesting

        Always excellent sources for further thought…

        http://www.projectrho.com/public_html/rocket/aliencontact.php

        http://www.projectrho.com/public_html/rocket/alientech.php

  • Harold Shaw December 19, 2022, 12:39

    Imo, Kipping makes some very poor assumptions here. The Copernican and Mediocrity principle aren’t interchangeable. The Copernican principle predicts that Earth isn’t a privileged frame of reference. This premise is the root for Special and General Relativity and the Standard Model. It can’t be discarded lightly. The mediocrity principle predicts that a randomly chosen data point will most likely be drawn from the main body of the data set. Kipping is correct to point out that we aren’t a randomly chosen data point. However, he also implies that knowledge of other data points won’t improve our ability to predict where we are in the data set of Life.

    Assume Earth is part of data set, and the early start of Life can’t be ignored. He is essentially asking “what if we didn’t have evidence of the importance of an early start?” All we need to secure the significance of an early is assume all habitable worlds are subject to events that can reset evolution of abiogenesis. Imo, his position here is a red herring.

    I agree that we shouldn’t judge people according to the complexity of their model for abiogenesis. However, within every field of science we encourage each other to move towards simpler models. Challenging the assumption that we must move towards the most complex model possible, the one predicts we are alone, is valid.

  • henry cordova December 20, 2022, 16:01

    Deliberately seeding another world could be considered a hostile act. The inhabitants of the world, or of a neighboring world which might feel it had some proprietary rights to it, might take umbrage at some outsider spreading life-forms around, especially if they were designed to establish an alien ecosystem.

    Introducing the invasive organism using “natural” methods (like solar winds or comets) would be totally irresponsible. It would mean the initiators of the panspermia were deliberately spreading a potentially malignant pathogen because of some deranged science project of their own.

    This scenario has been explored fictionally. In the TV production “The Expanse”, the solar system is infected with a dangerous synthetic life form, a bioweapon from an interstellar war fought eons ago. In the film, “Annihilation”, a strange phenomenon arrives from space and takes root in Florida (where else, eh?). It is not clear just what the “glimmer” is, but natural or artificial, it is toxic, and it is growing

    Even a totally benign microorganism spread on a desolate waste planet might become a threat to visitors who were not aware of its presence, or who might be susceptible to infection from it. And even a totally benign bug might evolve into something really nasty.

    You don’t go into your neighbor’s yard and plant vegetables. And when your exotic pet gets too big to handle, you don’t turn it loose in the woods.

    Panspermia is, at the very least, irresponsible. At worst, it could be considered an act of war.

  • Harold Shaw December 20, 2022, 16:12

    Please forgive for going off topic and referring to a past essay.

    Perhaps the Fermi Paradox is more productive as Fermi Dilemma. A dilemma refers to a question wither just to answers and Fermi’s challenge offered two bounds; a theory sufficient to make us one in a super-galaxy, another sufficient to explain undetected space faring people. The later is our ability to search the probability space for all possible footprints for space faring people.

  • ljk December 20, 2022, 18:02

    One cannot explore and settle a new world without destroying at least some of the original resources and beings there. So do we live with it in the name of the greater good? Or do we not expand into space and hope that somehow humanity comes up with zero point population growth? And do other species hold similar sentiments, or do they consider the Milky Way to be their manifest destiny?

    So much humanity has not really considered as we are about to enter the Final Frontier. What can be done to correct this?

    https://slate.com/culture/2022/12/avatar-2-way-water-white-savior-ecological-indian.html

    • Alex Tolley December 20, 2022, 22:44

      Consider a universe filled with many old species that have reached their “carrying capacity”. Is there room for humanity to expand into space beyond the solar system other than to explore and interact, but not expand populations and resource use?

      Unlike the expansion into the Americas where European technology allowed the land to increase its carrying capacity compared to the indigenous populations, the galactic environment will have reached the maximum carrying capacity based on far more capable and mature technology.

      OTOH, if we avoid the physical universe and just create a virtual one to expand into, then it may prove perceptually much larger and capable of housing more minds than even a maximally resourced solar system.

      What if all species go this route and can interface with each others’ virtual worlds so that they can interact with other species in the virtual world of choice?

      Would this scenario allow expansion without destroying existing physical worlds and extant life?

      • Robin Datta December 21, 2022, 9:10

        A virtual bacon cheeseburger ain’t gonna cut the mustard.

        • Alex Tolley December 21, 2022, 16:36

          When you dream of eating a bacon cheeseburger, does it not taste as good as the real thing?

          [And if we are already in a simulation, does that cheeseburger taste less piquant than a truly non-simulated one? ]

          Biologically, we have only so many taste [6] and smell receptors [~= 400], combinations of which provide all the flavors of the food we eat. But theoretically, the simulation software could vastly increase the number of different receptors enhancing our taste and smell appreciation. It could also extend our sight by extending the number of cones (4 instead of 3 provides far more color discrimination) giving the simulated person senses across the spectrum, from the IR to gamma rays, and potentially long radio wavelengths. All our current em sensor technology could be built into our simulated eyes and brains. So while our current simulation VR/AR technology is crude, advanced technology will reach and then surpass our real-world experience, offering a life that makes our current experience seem like Plato’s Cave.

          • Mike Serfas December 22, 2022, 11:03

            We only have so much insula to appreciate all the good things in the world, so I’m not sure increasing sensory discrimination would really make things “better”. But at least they could be more informative.

            I wonder, though, if we get tetra/pentachromatic vision in a more temporary and less dramatic way. There has been much research on eye tracking, and though seems all oriented at surveillance (isn’t everything?), it might conceivably be put to a different use. Suppose people sat down to a computer terminal, and as they looked around at the screen, the green values of each pixel changed depending on which specific part of the retina the person was seeing those pixels with at each moment. So some green receptors report a bright color and others report a dark color all the time for a given image, no matter how you look at the image.

            Well, the interpretation of vision is quite malleable – there is a famous experiment in which subjects became accustomed to looking at the world through optics that turned the world upside down, and had to reaccustom to normal vision. People who wear eyeglasses make a less dramatic but similar adjustment. So I suspect that if you were watching video on a computer for some days, your brain might start to accept that the green receptors in these scattered small areas are a different kind of photoreceptor than those in others, and so you could learn to use it to distinguish extra colors coded into the difference between the two green channels of the video, one of which actually represents terahertz or UV etc. (It seems odd to picture shoehorning this information ad hoc into the orderly structure of the lateral geniculate nucleus, yet we do just that with our recently evolved green-red receptor distinction) This might be done with multiple subsets of green receptors, and red or blue might be subdivided in the same way. To do this in practice isn’t appealing if it means some company spying on people over the internet all the time – the philosophical limitations of our society have choked off much of the possible technological progress we might have made – but scientifically the result should be interesting.

            Virtual reality illustrates that a rock (or at least a piece of doped silicon) can hide much more interesting detail than meets the eye. Maybe every stone and drop of water on Earth already conceals an unfathomable amount of information that we simply don’t know, at our level of existence, how to log into.

            • Robin Datta December 22, 2022, 23:38

              Tetrachromacy in humans

              Some giant bivalve molluscs have 15 pigments in their retinal epithelium.

              • Mike Serfas December 23, 2022, 15:54

                I’d heard of this, but I am surprised at the amount of coverage recently, and especially, the claims of practical utility. In the past, the tetrachromacy, mostly from X-mosaicism of partial “color blindness”, was recognized, but not thought to provide a strong practical advantage — nonetheless, even then, there were exceptions. ( https://pubmed.ncbi.nlm.nih.gov/8351822/ ). The number of color receptors in ordinary humans is also a little more mysterious than the textbook would say… https://pubmed.ncbi.nlm.nih.gov/34625301/

                Anyway, given these recent news reports of people who can genuinely distinguish shades others cannot, it seems a bit inexcusable for elementary schools not to have a sign posted in the lobby urging those who read it to get a special test. What resources of art might come from this privileged population? To think how alien and surprising Earth can look to humans with a copy of one gene a little different … imagine how much our understanding must fail to grasp an extraterrestrial world!

  • Mike Serfas December 21, 2022, 16:00

    Here’s an interesting wrinkle to throw into this conversation: https://hal.archives-ouvertes.fr/pasteur-02909671 According to this analysis, the last universal common ancestor of all life on Earth (both bacteria and archaea, and later eukaryotes like us) probably came *after* the evolution of major classes of viruses, such as single-stranded RNA viruses and double-stranded DNA viruses.

    Though I’ve long been skeptical that an alien virus could affect Earth, or vice versa, the arguments from this paper would seem to support the idea that if there is any common ancestry with another world, however remote, then it is conceivable that these viruses could cross over. Of course, most viruses are very specific to one or a few organisms, relying on recently evolved receptors to get in … nonetheless, there are exceptions to the rules now and then, or else SARS would never have hacked into our ACE2 receptor, and SARS-2 would never have crossed over to replicate so well in humans.

    Earth life is deeply infested with viruses. Cancer researchers study a virus called “SV40”, because it was the 40th virus isolated from the monkey cells that were being used to produce the polio vaccine. But they go deeper than that – much of our genomes is made of old spam copies of bits of virus that got into the DNA and stayed, in some form. Evolution has worked around them and it would be a terrible trouble to get rid of them all now, yet there are indications now and then that these transcripts really do still hurt human health ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3351582/ ). Sending a terrarium of virus-free organisms to another planet isn’t quite as simple as spraying them down with bleach and giving them a few nasal swabs!

    If Earth life gets established anywhere, in any amount, along side life of another sort that uses RNA or DNA, then there is probably some chance that the viruses we’ve evolved can get loose and lay waste to that ecosystem. Additionally, we often envision making these decisions on a sour-grapes basis — if we can’t study a planet to see if it has life, much less get there, then why not seed it with Earth life for a hypothetical future? Yet a thousand years later there might just be a massive vessel setting down on that planet, full of colonists who have had every viral nucleotide ever so carefully snipped out, whose tiny cell nuclei can replicate many times faster so that they almost have regeneration superpowers and tremendous resistance to aging – but can they stay on a planet infested with ancient, unknown viruses that have since evolved in an alien environment?

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