Mars Clay Findings Are GOOD: The Great Filter Could Be Behind Us

NASA has announced that Curiosity and Perseverance have found the strongest-yet evidence of life on Mars: vivianite and greigite. On Earth these minerals are found in sediments associated with microbial life.

Great Filter-Doomers will find this alarming. If life evolves easily (and quickly - in thermodynamics that's the same thing) then it should be everywhere. And yet, where is everyone? The galaxy appears to be dead. There must be a Great Filter between the appearance of life, and technological civilization leaving its solar system of origin.


It's worth pointing out that until about 700 MA ago, Earth was a boring microbial planet. There was basic multicellular life but until the Ediacaran, nothing that you could actually see with the naked eye, or that had complex organization. In fact for over a billion years it was stuck in a simple oscillation of build up oxygen, die back, build up oxygen, die back, encoded in the banded iron formations (in different redox mixes) visible in extremely old rocks like the ones above in Australia. An alien visitor would have sampled the boring microbial soup and moved on. Visiting a hundred million years later, it would have observed exactly the same situation. Life on Earth was very much like a "blinker" in Conway's Game of Life, with little sign it would ever break out of it. Based on our N of 1, thermodynamically, the appearance of life is likely (it was almost immediately after the Earth cooled!) - and similarly, the appearance of multicellular life is UNlikely.


For that reason, if there is a filter, there's a big question is whether the Filter is behind humanity, or in front of it. The discovery of microbial life on Mars, especially extinct microbial life, would be good news, in the same way that discovering an extinct civilization would be bad news. A thought experiment may help illustrate.

Imagine you send out a fleet of near lightspeed von Neumann probes. As they cover the galaxy, the reports come back to Earth: thousand then millions of planets with oceans of bacteria and/or blue-green algae, some living, some extinct, embedded in clay like the ones on Mars. But absolutely nothing multicellular, anywhere, besides our freakish Earth. Everywhere, simple one-dimensional ecosystems, some "blinking" forever like Earth almost did, but no dusty ruined cities, or eerily silent half-built Dyson spheres, or even alien cockroaches. Nothing beyond a Kardashev 0.001![1] Time to uncorck the champagne! The Great Filter is behind us! We're the first!

Now imagine the opposite case: ghost planet after ghost planet, civilizations that blossomed and then burnt out. Some of them had even sent out their own probes and learned their fate. We would be looking at our own future.

If we assume this Mars finding really is extinct microbes, we now have N=2 for the denominator of how frequently life evolves, and N=1 - where it never got past the microbe stage - a 50% rate of the Great Filter being behind us.[2] Assuming the principal of mediocrity, 50% of the aliens we're not seeing are microbes embedded in clay. 50% is hardly a guarantee of our eternal future among the stars but it moves the needle in the optimistic direction. You might think it would be boring to explore the Solar System and find only microbes on Mars, Venus, under the ice of Europa and Enceladus - but such discoveries should make you happy for humanity's future, especially if they're extinct.


FOOTNOTES

[1] Recently there have been efforts to establish a continuous Kardashev scale (rather than having only discrete classifiers for civilizations which surpassed certain benchmarks, "1" being the power output of a star); one paper assigns 2023 Earth a 0.7276 (Zhang et al 2023.) For very low Kardashev numbers, we could relate the SQ (sentience quotient) for intelligence to the Kardashev scale. Calculating a simple upper bound for the Kardashev number of "algal Earth" - assume a number of cells per meter of seawater equal to that during an algal bloom, times the surface area of Earth's ocean, times the energy budget of an algal cell, divided by the power of the Sun:

5.1x10^14 m^3 x 0.7 x 10^11 algal cells/m^3 x 10^-11 Watts/algal cell
divided by 3.84x10^26 Watts = 10^-12 Kardashev

-70 is the lower bound for SQ, to single-celled organisms, so we can say that -70 SQ converts to 10^-12 Kardashev. Humans have an SQ about +13. However human civilization cooperates to control more energy than a single human, so +13 does not correspond to 0.7276, but whatever the SQ of the human race as a whole, does. You can't get the Kardashev of a single human just by dividing 0.7276 by 8 billion because of the non-zero-sum effects of civilized cooperation.


[2] As written before, Venus had oceans until about a billion years ago. I would have liked to include it here as another microbial blinker planet that ran out of time before its own Ediacaran, with the evidence of both phosphine and microbe-sized UV absorbers in its upper atmospheres, as the remnant of its ecosystem. This would give us a denominator of 3, and even more confidence that the Great Filter is behind us. However, the famous phosphine paper failed multiple attempts at replication and two papers (Jiang et al 2024 and Egan et al 2025) have advanced good candidate abiotic explanations for what the absorbers could be.

Why Are UAPs Associated With Naval Aviation?

We're more likely to find artifacts from technology-using aliens - self-reproducing (von Neumann) probes - rather than the aliens themselves, or even to recognize and understand their signals against background, if any. Indeed, humans may be just at the technological threshold of building such probes right now, but we're far from any serious discussion of manned interstellar travel, and in fact it may never be biologically feasible. Such objects are likely to be found associated with lower gravity objects, ie the asteroid belt, where they can obtain materials and build more of themselves. The further they are from home, the less likely they are to adhere to some "mission", and the more likely they are to have mutated and been selected merely for fecundity (reproductive ability.) Therefore it's not obvious that they would be particularly interested in finding other examples of intelligence. They could very well be much more interested in finding other von Neumann probes, and humans might therefore not be the most interesting thing in the solar system to them. If this is the situation that obtains, this resolves a contradiction: other technology-using species have indeed appeared before us, but there's little evidence of them here.

If the von Neumann probes are built from metal, and one planet over the last few centuries suddenly has large metal objects moving around its surface (ships) and smaller metal objects moving much faster through the atmosphere - then THOSE might be interesting. You might expect the probes to be especially interested in locations with lots of ship and air traffic, and especially the ones with the fastest air-objects, especially if the fast air-objects come and go from the large metal objects on the surface. It's been observed separately by other writers that, from the standpoint of an off-world but in-solar-system alien observer of Earth's behavior in terms of natural processes, the appearance of metal objects in the atmosphere and then suddenly in orbit is the most interesting phenomenon that has appeared here for many millions of years at least.

The fact that it's US Navy aviators who have reported many of the UAP sightings is obviously relevant. Given that the reported observations are made by multiple modalities (naked eye, radar, thermal) and official US agency reports describe as likely mostly physical objects, it's unlikely these are glitches: that is to say, either they're real, or they're made up, possible as sort of intelligence or misinformation operation that we civilians are caught in. But if it's real, two questions are important to the hypothesis.

First: is there really a higher rate of UAP sightings around US Navy aviation areas (as there seems to be so far, with sightings concentrated around San Diego and Virginia Beach) or is this just bias because there are more instruments and observers there? Such is the frequency of these events according to the reports that a relatively low-budget operation with some weather balloons over a low-traffic area could move the needle on whether naval air stations are "enriched" for these objects. (If it does not make any such observations, it would suggest either it's a misinformation campaign, or they're real but concentrated around naval air stations.) Related: do JFK or LAX have similar sightings? Or Heathrow? Narita?

Second: is it really an American (or mostly American) problem? Is the pattern repeated around the world at other countries' naval air stations? China or Russia might not be interested in sharing this kind of information, but NATO allies might be. That said, if an unfriendly country discloses it is seeing the same thing, and it has no explanation, then it's much more likely that these objects are real, and at least are not human-created phenomena.

Review of Three Body Problem

Warning: spoilers.

The Good

Western readers will inevitably learn a lot about the Cultural Revolution period and the attitudes about it people are comfortable expressing in print today. During this interview and in his postscript to the American edition, Liu distances himself from any reading of his work as cultural critique, maybe a bit too strenuously. Whether he should be credited as pointing us to a Straussian reading or this is just pragmatic avoidance of political attention is not clear to me.

Related to this, Western readers in particular are keen to find parallels between Trisolaris and Earth to China and America. Again Liu himself states this isn't what he's doing, and in any event it's not clear which planet would stand for which country. Trisolaris goes through cycles of death and rebirth not unlike China's dynasties (in fact, in the in-novel video game, represented literally as China's dynasties) and Ye is even explicitly described at one point as emerging from the chaotic winter of the Cultural Revolution. The regimented, autocratic aliens of Trisolaris are coming to dominate the naive Earth - the easy-going, beautiful Earth that fluorished in ignorance, as a Chinese author might imagine America. But this doesn't really fit. For one thing, Liu certainly doesn't come across as having any romantic fantasies about America; and Trisolaran sabotage of Earth's rapid advance also smacks of Chinese resentment at perceived Western interference in its rise. If two opposing narratives can fit so well, then I think we're probably crowbarring them into a story where they don't belong. Then again, a symbolic scheme need not be entirely consistent. Case in point, in District 9, are the aliens Soweto residents, or clueless interlopers like the Afrikaaners? Likely both, at various points.

The single best feature of this novel is its explosion of this idea that any technologically advanced civilization must necessarily be a moral one; that humans are inherently and uniquely bad; and that therefore, contact with starfaring aliens can only improve our lot. (This idea of humans being uniquely evil is actually grossly anthropocentric, morally pre-Copernican, invariably casting the rest of humanity as evil, except of course for the enlightened individuals lecturing the rest of us. It smacks of teenagers claiming to be Satanists. Why not just reject Christian symbolism entirely? Because that doesn't make your parents as mad.) Things did not work out well for the natives of the New World, and that was contact between the same species. And Cortez and Pizarro were surely more technologically advanced than the Aztecs and Incas, so why were they not also morally superior? Hence the moment when the police officer almost can't wait to show Ye the content of the messages they found on the Adventists' secret ship and destroy her "beautiful fantasies." It's worth pointing out that almost every cosmologist or astronomer who has a position regarding sending messages to other stars says that if the space-phone rings, we should not answer. And yet in the real world, many such attempts to advertise our presence have already been made, on at least one occasion frivolously as an art project.

The constant frustrated attempts to understand Trisolaran seasons raises a genuinely frightening implication of the problem of induction as it relates to life on Earth. Once the Age of Enlightenment arrived, the idea that we did not understand our world (or could not understand it) in some very relevant way became terrifying. Early strange fiction like Hodgson began to explore this horror of the irrational, of a universe which at its base could not be understood. Philosophically speaking, there are two categories of incomprehensible universes:

• Type 1: We don't understand the universe merely because we have not had the chance to observe a full cycle or the full domain, but ultimately, the universe is still lawful. Asimov's Nightfall is an example.
• Type 2: We don't understand the universe because we cannot. The universe is fundamentally irrational, or at least unknowable to narrow human intellects. Lovecraft's Cthulhu novels are an example; also, frequently, Dying Earth stories.

In both cases, encountering the fundamentally irrational can bring about the collapse of civilization, insanity upon directly observing the unknowable, and sometimes even the dissolution of physical reality. However, the problem of induction and horror of the irrational were not ultimately examined here - on this count the novel ended up being disappointingly mundane for reasons detailed below. Still, in the real world, at the very least Type 1 encounters with the irrational asteroid impacts, Carrington events, and gamma ray bursts are scary enough - at this writing, there is an Oort Cloud object possibly hundreds of kilometers across moving toward the orbit of Saturn that had until now escaped notice.

Ye is the tragic character, obviously, and she is the best-drawn. This woman suffers so much trauma, but the worst is that she realizes possibly the worst thing that anyone has ever done in history is her own action - she sacrificed her husband and accepted the loss of her daughter, then found that what she thought was the one meaningful achievement of her life, turned out to likely to mean the end of the entire human race at the hands of equally immoral beings.

The frustrations introduced by the sophon particle is reminiscent of the Sisyphean problems plaguing CERN and keeping it from finding the Higgs boson (which we know eventually was found.) But it's worth pointing out that in 2009 there was an apparently serious proposal that time travelers (or the Higgs boson itself) were interfering from the future with CERN to prevent some catastrophe that the Higgs boson, if created, would foment. Alas, we still exist.

I usually enjoy unexpected pacing and structure if I'm being surprised rather than bored or confused, and in this case, I was more often surprised. For one thing, this is a two-protagonist novel (Ye and Wang.)


The Bad

You will note the novel shares a number of the following weaknesses with the genre in general. First is characterization. Outside Ye and to some extent Shi, we barely know who these people are. In Wang's case, we only find out he has a family when he goes home, then he doesn't think about them again, even as he travels around the world, or in the face of mortal danger to himself, or even a threat to the entire human race. He finds out that we're dealing with aliens, and he barely reacts at all. Even a Dan Brown protagonist at least wanders around a novel imbuing the revelations with a sense of wonder and profundity. Wang isn't even a mouthpiece for ideas.

Liu offers very few sensory descriptions of anything, except the village outside Red Coast. Ye's experiences there are described in conspicuous sensory terms that stand out. It should not be a surprise then that Liu grew up in a poor rural village.

For any reader familiar with near-Earth stars, it wasn't a surprise that Trisolaris turned out to be Alpha Centauri.

If we're applying hard science fiction rules, then it's too great a coincidence that the aliens are within a few millennia of our own technological level. Aliens are much more likely to be either trilobites, or "phyla beyond [human] knowing" to use Benford's term, than something at all cognitively similar to humans that comes here on metal ships. This is a point that many readers of science fiction will not mind, but will bother anyone familiar with current academic thinking regarding the Fermi paradox. The fact that they even feel the need to insult us - "YOU ARE BUGS" projected on our retinas - makes them seem a bit too human-like. In fact the entire description of the "real" internal behavior of the Trisolarans is far too anthropomoprhic. There was some mention of the "living computer" having been a real thing there, and their movements being much faster than humans', so I hope I'm missing some sleight of hand like the one Vinge used in Deepness in the Sky (the spider-aliens were in fact much more alien than they were portrayed earlier.)

Plot problem - if the goal is to disable scientists, then the sophons could do a lot better than create a spooky countdown in someone's visual field. You could blind them, or cause them to hallucinate. In the real world, hallucinations and even tinnitus alone can effectively disable people. Sensory disruption is much more effective than some higher order cognitive interference introduced by undermining ideas in a lawful universe. Furthermore this suggests a shockingly detailed knowledge of human psychology on the Trisolarans' part.

In the end I did not find that there were really new ideas developed in the novel; what looked like it would be an interesting exploration of the problem of induction or the rational nature of reality (see above) turned out to be industrial sabotage done by aliens instead of human enemies. The use of entangled programmed fundamental particles is interesting but so far beyond anything we think might be real that it's effectively fantasy. China Mieville has advanced the idea that the authorial voice of science fiction is one of radical authority - effectively, "here is how reality itself works. Accept it as possible in order to continue reading." (You might argue that limiting the ideas to known physics either elevates hard sf to the "correct" genre, and/or that it can only produce fictional worlds of straight line extrapolation that people in the future will regard as the early twenty-first century's answer to steampunk. But science and actual speculations thereon rather than just word play is what we know is real, and sticking to the rules of the real world is what keeps a story from being fantasy. This is why Star Wars is a a fantasy movie, masquerading as science fiction by giving its wizards and barbarians spaceships.)

A wild idea couched in the language of science even if the work is really fantasy, or even comedy (see: infinite improbability drives) can still be a good vehicle for thought, but unless you're showing us how to actually in real life unfold and program a proton, you don't need to devote so much space to it. This isn't a screed against exposition, which I think is unfairly devalued in science fiction. If you're introducing a new idea, you either have to stop and unpack it, either in the characters' voices, or through direct description. But the sophon programming section is unnecessarily long and actually became quite boring, the science fiction version of John Galt's sixty page monologue, and had nothing to do with actual science. Maybe this is a tendency of modern Asian fiction - Murakami's Hard Boiled Wonderland has a curiously long-winded description of skull-tapping and at the time I gave the author credit for doing something that I just wasn't getting, but I'm much less sure this is the case in a less literary novel.

I have a personal distaste for fantasy worlds inside science fiction novels. Spacetime folds that take characters back to their childhoods, neural interfaces that make their subconscious a real place, or in this case, a VR video game. It removes constraints from what the writer wants to do and becomes literary expressionism, which in novels (particularly those low on sensory description) seems watery and uncompelling.


In the end, after the hype, I was a bit disappointed. I'm glad I read it but the novel's strengths were really its different setting on Earth and historical perspective of the author. If this were an American science fiction novel it would be clearly mediocre.

New Approaches on What the Fermi Paradox Means for the Future of Humanity

I was lucky to attend a video lecture by James Miller, economist at Smith College, facilitated by Joshua Fox. Thanks for having this event! I contacted James to let him know I would be posting this and to let him proofread my recapitulation of his argument so as to avoid mis-paraphrasing him; my thanks to him for taking the time to correct me on several points. Of course any errors are mine.

Much of this is familiar terrain for those of us who spend our time considering X-risk and the Fermi paradox. Miller's thesis is that we are at a critically important point in human history, a window where we think that in the near future we can start colonizing the galaxy (the year 2614 at earliest, by this calculation) but at the same time where we are smart enough to destroy ourselves. Since it is not obvious that the galaxy has already been colonized by other civilizations, there may be a Great Filter stopping this from happening. Miller uses the analogy of a person about to climb a mountain, believing that everyone else who has attempted it has died in the process.

Several challenges were discussed by attendees. (If you attended the lecture and want to claim credit for your question, please comment below, thanks.)

1. It's too early to say there are no civilizations; it may not be so easy to detect them or rule them out. We're still discovering metazoans in Manhattan so it seems a little early to rule out von Neumann probes on low gravity bodies in the solar system. We've barely begun to catalog the fauna of our own ocean floors. We could not detect a twin Earth emitting the same radio energy (the C-index), even if it was orbiting Alpha Centauri. Miller points out that even if there were only a few civilizations in the Milky Way preceding us, "the galaxy is older than it is big", and these earlier civilizations could have colonized it already.
   
   
2. He made the point that the things which prove advantageous in the midst of evolving on a single planet might have no such advantages in terms of galactic colonization. Very true; I would argue that we are much more likely to find alien artifacts, than the aliens themselves, as all of us meat-creatures might be stuck on our planets while our machines colonize the galaxy. To that end, (my point) it's entirely plausible that the Solar System could be littered with space probes and we haven't found any yet, or did, and just didn't know what we were looking at.
   
   
3. I would therefore extend Miller's analogy like this. Only in the process of climbing the mountain, does our climber develop wilderness skills and begin to see things that resemble his own boot tracks, etc. and finally as he approaches the summit realizes that lots of people have climbed it, come down the other side, and their descendants have built large villages which due to his previous ignorance he has not been able to locate. (Or, maybe just some of their livestock, trained birds-of-prey, etc. have made it.)
   
   
4. Active attempts to bring ourselves to the attention of aliens have occurred (METI) and been roundly criticized. Miller notes that the risk of extinction from aliens over the next few centuries is lower than eg bio-terrorism or an intelligence singularity. True; but we still may be making life more difficult for our descendants. Related to this, he proposes an ingenious experiment that for a month we should shout our heads off electromagnetically, and see if there is any strange activity. While I agree it's unlikely we'll get invaded next week, I still think the risk:benefit does not work out and there are just too many unknowns, and we may be screwing our distant descendants. Miller suggested that enforcing a moratorium on METI-like activities is probably impossible.
   
   
5. He argues that technological singularities of the paperclip maximizer variety are unlikely to be a major contributor to the Great Filter, because we would be able to see the boundary of it as it expanded (unless it was doing so at light speed.) My concern with this is that, while an AGI might be much smarter than its creators, it is still not omniscient, and the impact of its actions could in principle still outstrip its ability to predict that impact. This is the story behind the rise of human intelligence and the sixth great extinction that we're living through, but has happened in pulses of endogenous extinctions throughout Earth's history (the rise of superpredators every fifty million years or so, the Oxygen Catastrophe). The lesson of evolution here on Earth is that the smarter things are, the faster their behavioral plasticity "catches up with them" in exactly these sorts of disasters, so to suppose that alien paperclip maximizers are immune to this problem is to argue that a qualitative change in ecological dynamics has occurred.
   
   
6. There were two (possibly unappreciated) related questions asked: one about civilization perhaps being bad for sustaining civilization (witness declining birth rates in the developed world) and another that intelligences might prefer virtual reality - involution - to expanding into space. Miller points out the passive version of the "baseball bat" problem: you can live in heaven, but if a bad guy comes and bashes your server with a club and you as you sleep in your VR pod, that's the end of it. (Related: dynamic complex systems like minds, in principle, tend to drift toward delusion and suffer inherent cyclic crises.) It's a thesis for someone in psychology or a related field to note whether there is causation or just correlation between the increasingly encompassing virtual reality-like entertainments available in the developing world, and declining birth rates.
   
   
7. One questioner asked about the distinction between intelligence and civilization - humans have had a "civilization" only since agriculture. This was a really original line of thought. Therefore, there could be many alien intelligences, but few or no civilizations. One solution for humans avoiding the Great Filter would be to abandon civilization and go back to hunting-gathering - not directly suggested, but this is the only implication of such an argument I could think of. The extreme number of assumptions built in to discussion of alien civilizations should always be pointed out - civilization is something that collections of human nervous systems do, and it is not clear it is a necessary consequence of intelligence. (As a physician I ask: do we assume the aliens will have similar EKG waveforms and liver enzymes as us? No, because that's ridiculous. So we do we assume that the even more complex activity of another organ, that we don't even share with other animals on this planet, is automatically going to be meaningfully similar?)

There's also a psychological point to be made about "big picture" arguments (the singularity, the Fermi paradox, the simulation argument, etc.) They have a tendency to converge on either prophetic religion-like conclusions (e.g. the singularity as the rapture for nerds) or Lovecraft (the estivation hypothesis, which was mentioned in a question and made me think about this.) When we talk about these things, there are many many unknowns. In such discussions, I think there is a tendency for the resulting arguments to resemble the internal contours of the human mind, more than any future events in the actual external world; hence their regression to religion-like conclusions. This does not mean such an argument must be incorrect, but it should make us suspicious when a big-picture argument hews too close to our "ontological test pattern. "

Consider in contrast cosmologists' models of the distant future of the universe, which concern physical objects which we can now observe and characterize, using rigorous mathematical rules. These models often seem boring, meaningless, difficult to understand, and unsatisfying. This is exactly how we should expect most models will seem of things outside our own and our ancestors' experiences, or beyond the scale of time and space to which we are accustomed and which we are built to perceive; the further outside their experience, the moreso. This occurred to me when we were discussing the estivation hypothesis, though overall Miller's arguments do not set off many alarm bells for this quick-and-very-dirty heuristic.

Origin of Life in RNA Computing: Independent Suggestion of Organic von Neumann Probes

Previously I had advanced the idea that, if intelligence has arisen elsewhere in the galaxy, it is likely to have colonized the galaxy in some form, and therefore we are more likely to find their artifacts here in our solar system than hear or understand their EM signals.  Specifically I argue that von Neumann probes are more likely to be entities of organic chemistry we find on low gravity bodies, that as natural selection is universal law that such entities - even if dispatched to gather information - would eventually be selected for fecundity; that is, they would inevitably become cancerous.  If the water that seeded the early Earth contained such entities, whether or not they were intact, the tumor detritis of these cancerous von Neumann probes would provide the template for life on ancient Earth.  

We have not nearly approached the amount of solar system exploration, or elaborated an abstract theory of how to recognize life or its artifacts, to be able to say we have absence of evidence.  Indeed we find nucleobases on asteroids, though so far we have no evidence so far that they originated from processes beyond the natural ones we are aware of.  

In a new paper, Hessameddin Akhlaghpour makes the observation that while the RNA information processing behavior of life on Earth is not Turing complete, with some additional (not implausible) molecular machinery, it would be.  He then argues that life originated with such a molecular machine and we have not yet found it.  (H/T Marginal Revolution)

Akhlaghpour H.  A Theory of Natural Universal Computation Through RNA.  arXiv:2008.08814

New Estimate for Number of Active Civilizations in the Milky Way

A summary:

• At a lower bound, it's estimated on average there is one 17,000 LY away. The number that is being reported is that this means at least 36 civilizations in the galaxy.
  
  
• They mention the problem of relying on M-class stars as abodes for life - because they're quite unstable (flares). I have not read the paper in detail, but it seems hard to understand, if there are only 36 star systems, why those couldn't all be G-class stars.
  
  
• They also estimate a lower bound of communicating for only a century (since we've been communicating for that long so we know it's possible.) If it's only a 100 year period, if we're hearing them now, they were active before agriculture.
  
  
• There's also the problem of being able to discern signal from noise at that distance - and not knowing what type of signal we're looking for. A useful thought experiment is the C-index, which is the distance at which we could detect a twin Earth with identical EM emissions. By most estimates, even if there were a twin Earth orbiting Alpha Centauri, we still today could not hear them. This leads the authors to conclude that interstellar communication is for all intents and purposes impossible.
  
  
• Therefore, any persisting civilization is plausibly more likely to be detected by self-replicating artifacts. This all reinforces the greater relative importance of looking for artifacts in our own solar system, which is something we can conceivably do with known technology in the near future, with less of a signal-to-noise problem.
  

Westby T. and Conselice CJ. The Astrobiological Copernican Weak and Strong Limits for Intelligent Life. The Astrophysical Journal. 2020 June 15.

The Singularity Will Be An Extinction Event, and an Endogenous One

There have been exogenous extinctions, ie not from an ecosystem's "internal contradictions." Examples are massive magma flows like the Central Atlantic Magmatic Province at the Triassic-Jurassic boundary, or the asteroid strike like the K/T Boundary. These were at least partly caused by out-of-context events that life on Earth did not influence. Then there are endogenous extinctions, which were caused entirely by the actions of the system itself, with no external disturbance. The best example is the Great Oxygenation Event, where the cyanobacteria inadvertently poisoned themselves, and paved the way for a whole new kind of metabolism. About every 26 million years, a superpredator develops and kills everything – humans are filling this role currently – and even if there's not an extinction, there's a local minimum in biodiversity and ecological robustness.

Since we're the aerobic beneficiaries of the Great Oxygenation, we like to narrativize this in the form of a teleologic happy ending. That is: the story becomes, yes the cyanobacteria poisoned themselves, but it was to make way for the glory of oxygen-breathing life. That oxygen they fatally polluted themselves with turned out to be an improvement, a new fitness landscape. Any endogenous extinction clears the way for evolutionary progress!

This is false. Of course the Great Oxygenation Event turned out to be survivable, because we're here looking back on it. But choose any other model example of a closed ecosystem where the endogenous activity of the local organisms is rapidly changing their environment, and you are unlikely to find that the majority of them are success stories. Things poison themselves, and end up with no descendants that can survive. (There is no argument to exclude humans from this phenomenon. Both deforesting Easter Island and the ongoing Great Carbonization Event are good examples.)


Two implications follow:

1. The reason for the Great Silence (ie the Fermi paradox) could be that there are many watery worlds out there which evolve local cyanobacteria, but they have their own endogenous shocks, and these do not result in a survivable planet, or at least in a richer potential fitness landscape. As in Conway's Game of Life, if they're lucky they either settle into a simple oscillating system (bloom, mass extinction, bloom, same kind of mass extinction, ad infinitum) or the ecosystem collapses completely and ends.

Speculation regarding this: we're fairly confident the first metabolism on Earth was sea vent iron sulfur organisms, using sulfur in what is now oxygen's chemical role. The Great Oxygenation may have only happened when it did, a full 1.5 billion years after the first life and at least 800 million years after photosynthesis appeared, because an asteroid delivered molybdenum, allowing nitrogen fixation and more efficient anaerobic metabolism. Whatever the reason, had this happened prior to photosynthesis, we may have ended up with an Earth poisoned with sulfur or at least with a massive amount of oxidized sulfur.

In an interesting parallel observation: we're also confident that Venus was once a wetter, cooler world that had a runaway greenhouse effect. One of the mysteries of Venus is the origin of all the sulfur in its thick atmosphere; to a first approximation all sulfur on Earth's surface is assumed to be from volcanoes, but why so much more on Venus? Another mystery is the identity of the small UV absorbers (about the size of bacteria) that form the dark bands in its atmosphere; one idea is that they're cells descended from ancestors that evolved at the surface and now can only survive in the more benign lower temperatures and pressures of the high clouds. If indeed these are the survivors of a Great Sulfuration Event, while the event did not result in total extinction, it limited the Venusian ecosystem to oscillate on a barren fitness landscape, just from the bad luck of having richer crust contents or earlier impacts with potential-enzyme-cofactor-bearing asteroids that allowed more efficient iron-sulfur metabolism.

(Recent evidence however suggests a massive volcanic event 700 MA ago that resurfaced the planet after massive flows; this which may be enough to explain all the sulfur. A gradual boil off of water remains quite likely, for two reasons – the D/H ratio on Venus is about 150 times higher than Earth, where comets have at most a 3 times higher ratio than Earth, suggesting loss to space of hydrogen from water and preferential retention of the heavier nucleus; and that such a massive volcanic event could have been caused by the loss of water, and the cessation of plate tectonics which allow a cataclysmic buildup of heat. It's interesting that the Siberian trap flows and CAMP happened during a period on Earth when the continents were crammed together and perhaps less efficient at letting out volcanic heat, though these events were still nowhere near what happened on Venus.)

2. If a technological Singularity occurs, it would be an endogenous extinction. In this case we are the cyanobacteria, and our extrasomatic adaptations are the contradiction internal to the system, and the AIs are our oxygen-breathing descendants. Like them, we produced the conditions that destroyed us and paved the way for the next phase of life. It's true that cyanobacteria and anaerobic organisms persist but do not dominate the world as they did in the Archaean. Even if cellular life survives the Singularity, being relegated to the role of cyanobacteria is unappealing for most.

But then there is another possibility, in which the AIs drive themselves extinct too. Think of this as the super-pessimistic case. Singularity optimists think we can benefit from or at least co-exist with superintelligence (becoming the equivalent of cyanobacteria is actually optimistic in this scheme.) Singularity pessimists think the event will kill all biology. Here, I suggest the super-pessimist position, which is that the Singularity may kill us, then also itself, in the final, most spectacular ecocide of Earth's history. Why? One theory is that any self-improving superintelligences will necessarily disassemble matter, including whole planets, into atoms that can be used for computation. But there is no principle stating that intelligence must always exceed power; that is, that impact of behavior must grow more slowly than ability to predict impact of behavior. Certainly it didn't happen with cyanobacteria, and given the sluggishness of our response to global warming it might not be happening with humans. Even if the AIs are in fact superintelligences, they are still not omniscient. As they're disassembling everything, they may get to the end of a predictive computation and realize that part of the code has gone cancerous and is replicating out of control (and consuming matter in the process) and can't be called back, or they're going to run out of power before they get to the next planet or star system, or overheat, or whatever problem an AI might run into.

Therefore, if the Singularity does happen, it would be just one type of endogenous extinction. If in a hundred million years, aliens or their self-replicating probes visit the solar system (if such things ever occur in the history of the universe) they might find its dusty, partly-disassembled remains, and file the data under "ecosystems that ended with behavioral/artifactual singularities" and then move on. Interestingly, we have already found old planetary systems that are far dustier than we would expect, with no explanation for the inner dust ring and a some constant replenishment process. Even this assumes that the self-replicating alien probes can get there before becoming cancerous dead-ends themselves.

Gamma Ray Bursts as a Reason for the Sterility of the Universe

One answer to the Fermi paradox is that we are in fact alone, because life - at least intelligent life - is vanishingly rare or completely absent. If we ever get probes to other star systems, we may well find that any water world has its local cyanobacteria, but nothing beyond that.

And what exactly is it that this star system has been so lucky to avoid by accident? Gamma ray bursts are an obvious candidate. A 2014 paper by Piran and Jimenez use the known frequency and distribution of GRBs and calculate the likelihood of an ecosystem-annihilating one. What they find is that for systems within 13,000 LY of the galactic center, there is a 95% chance of a lethal GRB in the last 500 million years, and out where we are it's about a 50% chance. They speculate that some of our past mass extinctions may well have resulted from a GRB (the Ordovician-Silurian extinction event has been speculated without much evidence to be such an an extinction.)

So, it may well be that the Great Filter, or at least a major component of it, is not something endogenous to the sequence of evolution, but rather something completely random and external. It is therefore meaningless to talk about the Great Filter being "in front of" or "behind us."

This may also mean that we really are alone in terms of intelligences which, though boring, is the options we should wish for, it were up to us.

Warm Spot on Europa Produces Plume

Image credit space.com

Current explanations for this warm plume (in fact, authors refer to it as a hotspot) are thermal inertia (basically, having higher specific heat than surrounding areas and so retaining heat longer than surrounding areas) or more excitingly, subsurface geologic activity - which would have implications for the evolution of life. Blog post here, paper here.

Trumbo SK, Brown ME, Butler BJ. ALMA Thermal Observations of a Proposed Plume Source Region on Europa. The Astronomical Journal, Volume 154, Number 4.

Molecules with MW > 200 Found in Enceladus Vapor

That's bigger than all amino acids and nucleobases. (Note, 9 months old, I had missed this before.) Press release here, paper here. (Postberg et al, Nature. 2018 Jun; 558(7711): 564–568.)

Asteroid Bennu is Ejecting Dust; Also, "Alien Tech" on Bennu? (Hint: No)

One solution to the Fermi paradox is that there's evidence around us and we just haven't noticed it yet. An estimate of 20 MA for colonizing the whole Milky Way has been advanced, and if von Neumann probes (VNPs) are possible, then they should be around us. We have a tendency to think of VNPs as industrial-age metal objects like Apollo 11, but organic VNPs could diffuse between low-gravity bodies when interstellar comets or asteroids pass through solar systems. Therefore, when we start finding some interesting high molecular weight organic polymers with non-random monomer sequences in the sample-return specimens from asteroids like Bennu, we should seriously consider that this might be what we're looking at. It is therefore interesting that Bennu is ejecting material (see here and here), which would be required if the VNPs are cellular- or molecular-scale chemical replicators that spread passively.

Here ends the serious part.

Admittedly this is an extraordinary hypothesis, and it requires consistent extraordinary evidence to support it. However, noticing that asteroids have boulders on them isn't extraordinary.

Look! Boulders! And they're circled! Gosh, that MUST be alien tech!
One excitable UFO-hunting schmendrick insisted (after doing a complex analysis in Microsoft Paint, i.e. circling the boulders) that Bennu is "littered with alien tech". Then so is the construction site near my house! So is the desert! There are boulders all OVER the place - my gosh, we're surrounded by alien tech! Run! Apparently skulls have also been spotted. Space pirates? This is a particularly morbid form of pareidolia.

More on the C. elegans that Survived Re-Entry During the Columbia Disaster

Living roundworms made it intact to the ground after the Columbia crash, as noted multiple times before (here and here.) There is more information in the article about their level of protection: "'They sustained some heat damage to exteriors, but that's about it,' Szewczyk said. The thermos-size metal container holding the nematodes was housed inside the locker of a crew compartment that was reinforced specifically to protect the materials inside. Once that compartment ruptured, however, the nematodes still survived the crash to Earth thanks to the locker's build, Szewczyk said. The C. elegans stayed alive upon impact because by the time that part of the shuttle fell to the ground, it had already decreased in speed, allowing the nematodes to touch down more gently." A locker is much less protection than being deep inside a solid chunk of rock.

This has obvious implications: "'From an astrobiology standpoint, the important thing was that if you had a multicellular organism going through the atmosphere you can have interplanetary transfer of life by natural means, and Columbia demonstrated that,' Szewczyk said. 'It was a fortunate thing to demonstrate that in the unfortunate circumstances that there were.'" Their descendants are kept at the University of Minnesota.

Ice Volcanoes on Ceres May Provide Replicators Means of Spreading

Extraterrestrial replicators (be they naturally-evolved, or von Neumann probes or the mutant descendants thereof) are at least as likely to be based on organic chemistry as on clanking iron-age technology, as is often imagined. Material returned from comet Wild-2 showed that it was actually an extraterrestrial comet, and had amino acids on it. Other investigations have shown the presence of nucleobases (the components of DNA and RNA.)

Even Arrhenius-style "panspermia" spread by passive diffusion on astronomical timescales is not implausible, as our Oort Cloud has mixed with close-passing stars' clouds on the order of once every 0.1 MA (and we should assume this happens to other stars as well.) However, for passively spreading replicators, higher-gravity bodies like planets or large moons are dead ends because they have no means of escaping the gravity well.



Water geysers on Enceladus, from space.com
This is why comets and wet carbonaceous asteroids are the best places to look, and why the Hayabusa-2 probe on Ryugu is so important. Same for the Dawn probe. Europa and even Enceladus may be a tough sell as passively escapable gravity wells, but now we see evidence of active water volcanoes on Ceres through its life span.

Look for RNA-World Rock Strata on the Moon

Schulze-Makuch and Crawford show in Astrobiology that that the Moon may have briefly been habitable - either (two options) about 4.5 billion years ago, or 3.5 billion years ago, for a few tens of millions of years, with an atmosphere and some liquid water (Gizmodo digest here.) Since the moon was formed after an impact with the early Earth, we should assume they had many of the same starting materials. The moon had less surface area and less time, and split from the Earth prior to even the earliest suggested prebiotic activity around 4 billion years ago, so it would have had to develop its own life - it could not have been "seeded."

The Moon with life (although terraformed.) From Techeblog.
Recent work by Tashiro et al suggest that a 4 billion year old rock stratum on Earth shows evidence of biological activity and may even be the fossil result of an RNA-World stage in the evolution of life on Earth. If it existed on Earth, it also could have existed on the Moon. It's not as though that rock stratum is exposed everywhere on Earth (the Tashiro people used samples from northern Labrador, Canada.) But it's interesting to think that the same stratum could have existed on the Moon if prebiotic chemistry took a similar course - and that those strata may be much easier to find and more widespread given the inactivity of the Moon relative to Earth.

Attempts at Interstellar Communication: Receipts and Responses Within Your Lifetime

tl;dr Lots of scientists are on record saying that broadcasting messages to nearby stars is dangerous. If you take other low-probability high-consequence existential risks seriously, you should consider joining the effort (resources here.) Compared to some of the problems the X-risk community is used to thinking about, it would be relatively easy to stop active SETI (METI) and protect the future of life on Earth.

A very philosophically-minded Native American in the pre-Columbian era, sitting on the beach at night, might have thought: there might be a beach just like this one, far across these waters. And if we set up large bonfires, we can let them know we're here! What a joy it would be to meet and exchange culture and technology! We know how the exchange actually played out; if it had come a few centuries earlier, it would have been the Norse landing in New England and Virginia, and likely would have been even worse. In any event, if our pre-contact philosopher would've known exactly how friendly those people across the water would be, he would've abandoned his plan.

This was the result of contact between two groups of the same species that had been briefly (in biological terms) separated. Based on simple evolutionary psychology, contact between two completely unrelated species would likely be much, much worse. But in contrast, revealing the strangely and hypocritically self-flagellating psychology of certain people, you don't have to look far for arguments that contact between humans and aliens would necessarily be beneficial to us - because we humans are so dirty and sinful (except for the people pointing out how sinful we are of course), and any aliens technologically advanced enough to visit us[1] would necessarily be morally advanced as well (again inconsistently, morally advanced as evaluated by the sinful human making the argument.) There's no valid argument in favor of METI, and every reason to think it should be considered suicide for Earth's entire ecosystem, not just for humans. And yet it's been done repeatedly, sometimes for reasons as silly as art projects.

Consider the following list of stars that have been targeted for such contact attempts, and which are close enough that a response (or a visit, if they can travel at light speed) could be received in the medically optimistic lifetime of someone born recently.

Star	Sun-like?	Planets?	Earliest Response
Teegarden's Star	red dwarf	possible	2036
GJ83.1	red dwarf (flare)	no evidence	2040
GJ273b	red dwarf	YES, SUPER EARTH IN HABITABLE ZONE	2043
Gliese 581	red dwarf	YES, POSSIBLY IN HABITABLE ZONE	2050
Altair	white (A)	no evidence	2051
GJ526	red dwarf (flare star)	unlikely	2059
HIP 4872	red dwarf	no evidence	2069
Kappa Ceti	YES, but frequent flares	no evidence	2069
HD 245409	cool orange/hot red dwarf (K-M)	no evidence	2077
55Cancri****	YES	YES, POSSIBLY IN HABITABLE ZONE	2085
HD 10307	YES	unlikely (companion)	2085
47 UMa**	YES	possible	2093
Gl 777	YES	possible	2103

*Where there are asterisks, numbers of asterisks = # of contact attempts

This is by no means an exhaustive list of all messages, only those for which we can receive a response by 2110 - and only those which are publicly reported.

The argument against active SETI (or METI; Messaging ET Intelligence) is simple. Any aliens which receive the message and have the ability to travel to our solar system are very likely far advanced. Whether or not they intend to harm us - if they, it, etc. even has "intentions" - is immaterial, as any contact with them is overwhelmingly likely to be catastrophic for Earth's ecosystem as a whole, including the human race. Arguments that the aliens will be (or for some reason must be) "nice" are comically narrow-minded and provincial.

The best arguments in FAVOR of active SETI appear to be 1) if we remain silent, then we can infer other species are likely to have made the same decision and it's inconsistent to remain silent but keep listening. 2) Advanced species probably already know about us, and these efforts don't much increase the chances of being detected.

To #1, even assuming the self-indication assumption-reasoning here doesn't demand bizarre causality as Nozick argued with respect to Newcomb's Paradox, given the likely severe consequences of a visit from a species more advanced than our own, I think joining in with all the silent species and being part of the problem (i.e., leading to the Great Silence) is quite a good trade. Notice that in our own ecosystem, most animals are quiet, unless they can quickly escape by flight or into burrows, are hidden by darkness, or are surrounded by conspecifics. Those of us who assume that aliens must be friendly somehow always insist that natural selection stops applying to advanced species and across interstellar space.

To #2, if the best argument really is that "they already know we're here so we're not increasing our chances of detection by potentially destructive aliens THAT much", which is literally the argument made by Jacob Haqq-Misra, Chief Scientific officer of the Lone Signal project, then that tells you a lot about how well-thought -through the whole enterprise is. What's more, it's absolutely false. The C-index is a quick and dirty measure of our detectability - if there were a twin Earth, giving off the same amount of electromagnetic noise that we are, how close would we have to be to detect it? Currently, about 3 LY, meaning we wouldn't even be able to hear ourselves from the next closest star. A powerful directed message on the other hand would be much easier to detect from a longer distance - so these messages are in fact likely increasing the probability of our detection substantially, at least at the target stars. Otherwise why are they even sending them?


These projects are ongoing. The problem has been discussed at conferences with approaches including a moratorium backed by international law (so far only talk.) These things are slow. One approach may be to go directly to the telescopes sending the messages, as there are a limited number of such installations. In decreasing magnitude of offense with those messages, they are:

Eupatoria (Crimea, Ukraine) - 7 targets, 11 transmissions
Arecibo (Puerto Rico, USA) - 4 targets, 4 transmissions
EISCAT (Tromso, Norway) 1 target, 1 transmission (an art project!)
Jamesburg (Carmel, California, USA) 1 target, 1 transmission (crowdfunded!!)

In addition, Alexander Zaitsev is a Russian astronomer who is far and away the individual most responsible for driving METI efforts. Douglas Vakoch is a METI proponent here in the US.

Lots of scientists are on record saying that broadcasting messages to nearby stars is dangerous. If you take other low-probability high-consequence existential risks seriously, you should consider joining the effort (resources here.) Compared to some of the problems the X-risk community is used to thinking about, it would be relatively easy to stop METI and protect the future of life on Earth.

[1] I purposely avoid the word civilizations, because that is a term which describes an entity with certain characteristics that humans can collectively form. Whatever activities groups of aliens form, it will not appear like any "civilization" we would recognize. "School", "herd", "flock", "swarm" are all terms that are at least as likely be useful to human impressions to describe the collective entities that we see.

Another Interstellar Asteroid - This One a Permanent Resident of the Solar System

Asteroid BZ interested astronomers right away, because it is retrograde, in a 1:-1 resonance with Jupiter - suggesting that it was captured from outside the solar system just as ours formed, and is therefore older than the rest of the solar system.

But more interesting than that, it took several unlikely events for it to be captured and continue in a stable resonance over time (see last paragraph in the Orbit section.) This very strongly suggests that there are interstellar objects passing through the solar system all the time. For such an object to be captured so quickly, so early in the history of the solar system means that there must be enough of them to get trapped by freak aligments. Another way of looking at it is that fast = likely.

This is consistent with a similar argument made about Oamuamua, an interstellar asteroid that is currently passing rapidly through the solar system. Within a year of the first telescope that could detect such an object being activated, it found such an object. Good luck? Or constant interstellar material passing through? (It didn't take long to find BZ either, once we started looking.) The relevant point is that while the vast distance between stars is often cited as a form of quarantine for macroscale beings like us, it is certainly not such a quarantine, even on brief geological time scales, between pools of organic molecules. More here about periodic close passes between stars and interstellar mixing here and here, and (most speculatively) that if von Neumann probes exist, they are likely to interact with comets and asteroids with organics, rather than planets.

Super Earths: More Surface Area to Evolve Life, but More Gravity to Keep You From Leaving

Super-Earths have more surface area and may be more likely to evolve life merely for this reason. But ironically those planets have higher gravity that makes them harder to get off of - and that life is therefore more likely to be trapped. This is similar to the idea that planets closer to the galactic center might be more likely to have life because they're older, but less likely to have life because those planets are more subject to bombardments triggered by more-frequently close-passing stars, supernovas or gamma ray bursts. When the same cause (larger terrestrial planet) can plausibly have two contradictory effects and we can't decide which one will dominate, that shows how little quantitative knowledge we have and how little we really know with any confidence.

Last post about alien evolution: Method Proposed for Detecting Exotic Biochemistry

Finding Extraterrestrial Organics is Old News; Let's Look for Evidence of Life

There's a new mass spec study[1] of crystals from two meteorites, one of which in turn has material originating from two separate parent bodies. The objects were about 4.5 billion years old, i.e. dating to the birth of the solar system, and showed evidence of organics resulting from aqeous reactions. Some findings of interest: "...signatures of low-mass C5 to C10 hydrocarbons at around 70 to 200 atomic mass units." Not much benzene, suggesting that any aromatic rings are locked up in larger structures. We're finding organics everywhere we look it seems, including Ceres, and that includes even amino acids and nucleobases. Given how quickly after the Earth formed we started seeing evidence of self-replicating molecules (at least the ancestors of cells, if not cells themselves), this means that life originated quickly on Earth, and therefore was a highly probable event.

It's also relevant that polyaromatic hydrocarbons (PAHs - for instance, tar, graphite, anthracene in coal, and fullerenes) have been found in nebulas, as well as in Titan's atmosphere. Not only are they thought to be quite common in the universe, but possibly crucial to the origin of life (see PAH World Hypothesis.) PAH's are predicted to make up a large portion of the carbon at the surface of carbon planets. While carbon planet systems (unlike our own silicate system) were theorized only recently, it turns out that the Hypatia Stone, a bizarre meteorite found in the Egyptian desert, is loaded with PAHs and originated from outside our solar system - possibly as impact debris from just such a planet.[2] (It's becoming increasingly clear that objects from outside the solar system enter it frequently. First Wild-2 (which had amino acids in it), then Oamuamua, and now Hypatia. We've found these things on the Earth's surface without looking that hard for them! Given these observations, we should expect that interstellar mixing on relatively short geologic time scales is the rule.

This suggests several things and begs several questions.

- If a pile of complex molecules were delivered to Earth - say, a bunch of RNA that survived intact inside an impactor - that pushes back the question of the origin of life, but it also suggests it's very likely elsewhere.

- Have we looked for polymerized RNA or amino acids? Mass spec can detect and distinguish small fragments.[3]

- You might ask, why RNA? Why assume any similarity to Earth biochemistry? This raises the larger question of, if there is active extraterrestrial biochemistry in asteroids, how could we detect it? This is the question asked about desert varnish (which has been speculated as evidence of a shadow biosphere of non-DNA based life operating here on Earth under our noses.) If we did find alien biochemistry, how would we know what we were looking at, against the background of organics that we already know is there? While we haven't seen anything that obviously screams "alien biochemistry", that's the point - HOW does something look if it screams "alien biochemistry"? Are there general principles of such systems? You can't just look for macromolecules - if those are composed of the some monomers, they won't necessarily carry information (e.g. aliens trying to figure out our biochemistry from sequencing the fatty acids in our membrane phospholipids will not learn very much.) So it has to be a macromolecule with a limited number of discrete subunits. So far our samples have been limited t one biosphere. If we ever get enough complex organics from a sample return mission to be able to afford to destroy some of it in aqueous chemistry experiences, that will be a boon to astrobiology.

- If there is such a thing as a simple space-borne organism - or even the remnants of aberrant von Neumann probes that have "gone to seed" after eons-long selection for fecundity over their exploration functions - it would make sense to be adapted to low gravity bodies that are cheapest to move back and forth between. If Earth's biosphere is just overgrown von Neumann probes, that might just be because we're a dead end at the bottom of a gravity well.

Previous post on alien evolution, First Interstellar Asteroid? It's Interstellar, But Not the First We've Seen


REFERENCES

[1] Queenie H. S. Chan, Michael E. Zolensky, Yoko Kebukawa, Marc Fries, Motoo Ito, Andrew Steele, Zia Rahman, Aiko Nakato, A. L. David Kilcoyne, Hiroki Suga, Yoshio Takahashi, Yasuo Takeichi and Kazuhiko Mase. Organic matter in extraterrestrial water-bearing salt crystals. Science Advances 10 Jan 2018: Vol. 4, no. 1, eaao3521. DOI: 10.1126/sciadv.aao3521

[2] Georgy A.Belyanin, Jan D.Kramers, Marco A.G.Andreoli, Francesco Greco, Arnold Gucsik, Tebogo V. Makhubela, Wojciec, J.Przybylowicz, Michael Wiedenbeck. Petrography of the carbonaceous, diamond-bearing stone “Hypatia” from southwest Egypt: A contribution to the debate on its origin. Geochimica et Cosmochimica Acta, Volume 223, 15 February 2018, Pages 462-492.

[3] Zhaojing Meng and Patrick A. Limbach. Mass Spectrometry of RNA: Linking the Genome to the Proteome. Brief Funct Genomic Proteomic. 2006 Mar; 5(1): 87–95.

First Interstellar Asteroid? It's Interstellar, But Not the First We've Seen

Information here and here. Based on the velocity and path, this asteroid originated from outside the solar system. This is a great additional finding, but not actually news! Comet Wild-2 was the subject of the Stardust sample return mission, and analysis showed more than a few interesting things: that it contained the amino acid glycine, and that the nitrogen isotope ratio showed that the object likedly originated from a different solar system.

A point of interest here is that since the solar system's origin, there must have been multiple close passes by other stars - close enough that our respect Oort clouds would mix at the margins, and material would be exchanged between star systems. We have now verified this logical inference visually, and through direct chemical evidence.

Previous post about alien evolution, Life's Origins at Four Billion Years Ago; Implications For Our Future

Organics on Ceres Are From Ceres (not from other impacting bodies)

The organic material on Ceres, while intriguing, appears to be native, rather than delivered from other impactors. So says data from the Southwest Research Institute at the 2017 Astronomical Society meeting. The possibility of simple organic replicators on low-gravity bodies in the solar system ("space viruses", to be dramatic) an interesting one, and is one form (or one part) of the pan-spermia hypothesis that's been considered for over a century, going back at least to Arrhenius. (Space viruses might also be the only evidence we would ever see of alien life or even an alien singularity.) What this tells us is that the large majority of material on Ceres, and presumably on most large old asteroids, is native to those bodies since the dawn of the solar system.

What the findings mean for the "space virus" hypothesis is that we can be more confident that Ceres is not crawling with foreign space viruses - although if there is a replicator that can use the typical organics on large asteroids as building materials, that's not what you would usually see. That is to say, when an organism gets infected by a virus, the organism isn't infiltrated with foreign matter, but rather with a tiny bit of foreign matter that then rearranges the atoms in the organism into copies of itself.