Want to talk about aliens?
Love Astrobiology. I worked in population genetics and know a few astrobiology people. (I was in physics before that). It is super cool.
There are really 4 main points I want to make, where sci fi gets it really wrong. And SFIA gets it a lot more correct.
If there is life on other planets and star systems then it is either panspermia or so utterly different from life as we know it. It will not be compatible with us in anyway. Basically you can't eat alien fruit. That is it won't have DNA.. it will probably have possible DNA analogue, but probably not specifically DNA. IT wont' be 20-22 amino acids. etc. It will almost definitively be carbon based however. Other base atoms just don't work. At ALL.
Simple bacteria is NOT simple. It has more organisation and complexity that an entire vertical manufacturing facility and then some. Simple life could be really common, but by simple something much much simpler than a bacteria. Self replication is what life really is. And you don't need to be as complicated as bacteria if your not competing against bacteria.
If there is life there then it would be trivial to detect. The whole "but would you recognise life" is a bad star trek trope up there with "beings of pure energy" and silicon based life. Once something can self replicate, even very slowly. It totally dominates the local chemistry of everything. Evolution will happen and then in just millions/billions of years then it is everywhere as well. Gray goo IS life. Really really. a single e-coli cell left to replicate unchecked would be the mass of earth in just a few days. We are a grey goo disaster!
Even with panspermia sorting out earth contamination vers native life in something like mars is trivial so trivial it is kinda weird how nasa is with the contamination protocols. It is up there with moon astronauts decontamination.
So my belief on the resolution of the Fermi Paradox is at least one great filter and a lot of major filters such that a civilisation in galaxy is very rare. What those filters are is best for perhaps another thread. like specifically on filters. Or just on the relevant SFIA episode since it is covered well.
Also no FLT. Just the universe we live in.
You have a good idea of the subject delt0r, but I respectfully disagree with the following points:
While I totally agree with you that the biochemistries of exoplanets and Earth will be 90% of the time incompatible, I don't think that each planet with life will on it will have radically different, exotic biology. Certainly, on average, each planet may have life inhabiting different biomes, utilize different forms of bioenergetics, have differing trophic levels and so forth, but parallels will appear as examples of convergent evolution. Wings, hair, scales, eyes, exoskeletons, endoskelatons and other basic traits all have evolutionary uses independent of chemical composition. So what if an alien's eye is made out of tiny indium needle-like hairs that sense pressure and heat instead of visual light in a cold, high-pressure atmosphere - the point is that the biological imperative for sensing one's environment is there. The real differences occur when natural selection interferes and gradually alters the appearance or even use of that trait, sometimes removing it or adding something new to it.
Given the sheer variety of possible biological pathways that only carbon-based, H2O-solvet organics ALONE can take alone, it would be a safe bet to maker that innumerable parallels of Earth-life could arise on a planet, with even more dissimilar, yet carbonaceous life based on similar chemical processes spawning - all via abiogenesis. I understand that you feel as though each example of abiogenesis will create radically-different life-forms per each environment, but considering that there are predicted to be billions of Earth-like worlds in the universe, statistically Earth-parallels will be present. This ignores for the moment other habitats that can make extremely different life-forms. In the universe at large, abiogenesis would be the most likely way for life to get started, perhaps even multiple times on a single planet. Panspermia could be possible in small, tightly-packed solar-systems like TRAPPIST-1 (which probably doesn't have detectable life in it, but that is beside the point), but aside from that the hurdles involved with getting a single organic cell from one planet to another are extremely challenging.
This is incorrect. Grey-goo and other forms of nanotechnology do not strictly meet the scientific definition of life, biological or otherwise. They can be likened to viruses, which are also not 'alive' in the academic sense. This is somewhat controversial, since defining 'life' is tricky, but nevertheless grey-goo technology cannot be consider alive in most cases. See en.wikipedia.org/wiki/Life#Definitions .
Furthermore, it is impossible for a replicating swarm to self-assemble so fast that they can overwhelm the surface of a planet in days and/or consume it entirely. The energy requirements for them to do so would be huge, and the heat created by them doing that at such a rate would produce so much infrared waste heat that they would vaporize themselves while replicating. This is a sci-fi trope, which is ironically something you condemn in your post. If the nanobot/bacteria can diffuse the produced waste heat in any-way, they then gain mass added by those facilities - exponentially slowing their replicatory process and growth rate.
I'm not entirely sure what you are saying here. If you are pointing out that it is an unnecessary for NASA to decontaminate their rovers because Earth-life was originally from MArs anyway, then this is fallacious thinking because enough time has elapsed in dividing the biology of the two planets to make an addition of different organisms inimical to the native life. Plus, outgoing Earth-probes are sterilized to prevent cross-contamination. If NASA one-day finds life on Mars, it would be seriously disappointing if was just a colony of UV-resistant bacterium that hitched a ride on a early rover landing and proliferated in the following years.
I'm not talking macroscopic things. I'm talking chemistry. Litterly DNA. You can store information in a LOT of different carbon based molecules. I mean litterly just about an infinite variety. We don't think DNA is the only thing. In fact if we found DNA in any extraterrestrial life even with different bases (ie extras over AGCT or not AGTC at all) it would be a very very strong case for panspermia.
Even with billions of earths, There are Trillions apon trillions of possibilities here. Finding something the same chemically in the entire Observable universe is very improbable.
Not really sure of what point your trying to make here. Gray goo disasters are a sci fi trope. The math basically means they don't and can't happen. There have been some papers put out about it. Self Replication no matter how (technically life or not) is all you need for "grey goo". AKA life is a observable case of grey goo.
Mars is so hilariously more harsh than just UV. Oh and there isn't any such thing as UV resistance. You can't have DNA for that! We use UV to sterilise labs and equipement as a standard procedure. It kills everything.
But working out that is earth bacteria is again so cheap and easy. Its a simple DNA sequencing test.
I was referring to both the macroscopic organics and the microscopic processes that contributed to their evolution. While different organics and biochemistries are indeed possible, and DNA as a biological information-carrier has many alternatives like anhydrohexitol nucleic acid or HNA, this alone is not stable ground for proclaiming that DNA is utterly unique in its specific molecular configuration. Analogs will be present. Further, there are limitations to the amount of possible configurations organic matter can develop within natural laws. Biophysics follows certain rules which in turn curtail biological configuration. While there are certainly many thousands of possible ways carbon organics alone can manifest, and indeed finding a close analog to Earthly life may be improbable on a chemical level - there is not an infinite amount.
The point I am making is that you cannot simply call a chemical/mechanical process 'life' because it self-replicates. Many natural processes on this planet self-replicate, and we do not consider them alive. Crystals, viruses, certain types of clay and even fire each have 'self-replicating' qualities, yet clearly these systems are not alive. Grey goo and other forms of nanotechnology, whether physically possible to engineer or not, do NOT fit the current definitions of life. Perhaps in the future we can broaden our understanding of life with newer, challenging discoveries. Until then, those processes and similar systems do not equate life.
No, there are bacterium and OTHER life-forms, some more complex then others, that are UV-resistant. Not immune, but resistant. Furthermore, a surprising amount of bacterium have survived the disinfectant process on Earth. Obviously there is a limit to how much UV a biological system can withstand before too many chemical bonds are broken, but many species can be highly resistant to even ultraviolet-C radiation treatment (the kind they use for cleaning). According to NASA, almost 250000 members of 370 strains of bacterium survived their sterilization procedure on various rovers sent to Mars, specifically in this case Curiosity. Of course, a combination of freezing temperatures, low atmospheric pressure and intense radiation kills many organisms off once on Mars, but some especially hardy species can survive, especially if they can make it under the Martian topsoil. These trouble bacterium are mostly from the Bacillus genus, but a surprising amount come from other, less tough species. Research the Bacillus bacterium on Wikipedia, they are a natural marvel: en.wikipedia.org/wiki/Bacillus
The Main report of bacterium contamination can be found HERE: sciencevibe.com/2018/01/10/nasa-admits-contaminating-mars-still-alive/
Also, as a point of interest here, there are many ways organisms can resist UV and other types of ionizing radiation. Here are just a few examples that you can look into, and while they probably cannot survive on Mars, their evolution remains intriguing:
The extremophilic bacterium Deinococcus radiodurans is the most UV resistant strain currently known. It, along with the other animals on this list, owes its radiation-resistance to hyperacceleratory cellular regeneration properties. Link: " en.wikipedia.org/wiki/Deinococcus_radiodurans
Members of the Bdelloidea class of freshwater rotifers can withstand crazed amounts of ionized radiation via a mix of tough biology and hibernation precautions. Link: en.wikipedia.org/wiki/Bdelloidea
Onto insects. A few members of the parasitoid wasp family of Braconidae can withstand up to 180000 rads of ionizing radiation at a time (1000 rads at once will condemn a healthy human to a slow, painful and certain death). Link: en.wikipedia.org/wiki/Braconidae
Finally, the largest radiation-resistant organism on this list is the humble scorpion - who can survive up to 135000 rads of radiation. In addition to having a high cellular regeneration rate, they also possess a fluorescent pigment that reflects UV rays efficiently. While this alone is used mostly for navigation, they are extremely tough to kill by direct radiation exposure. Link: www.scorpionsetc.com/scorpions-what-is-truth-and-what-is-wrong.html
In conclusion, it is entirely possible that certain organisms could hop over to Mars from Earth, or even vice versa if Mars has life and we unwittingly bring a sample back. Luckily for you, this is intriguing evidence for the possibility of panspermia occurring in solar-systems.
Anyway, If you wish to continue this conversation, I would like to tentatively suggest that you improve your grammar in some way. Your writing is very difficult to understand. I mean no disrespect if English is not your first language, but I get the feeling like most of my quibbles are due to misunderstanding.
Yes of course but I'm honestly setting myself up for dissapointment. If you'd do a grand survey of life on our planet the vast majority of it is kinda boring. The only exciting thing about any of it were we to find it elsewhere in the solar system would be that we found it elsewhere in the solar system.
Don't get me wrong, finding bacteria like organisms of any kind anywhere outside of Earth's biosphere would be a discovery of epic proportions. I'm just not expecting to find anything we can interact with in a meaningful way. The general population would find it's interest fade quickly just as landing on the moon because boring in the early 70s.
I simply believe that if we find alien life in the galaxy it won't be more complex than single celled life forms. I'll rate that a 70% likely with no scientific proof other than my pessimistic gut and the timeline of life on earth. After all life on earth is about 3.5 billion years old and it too nearly 3 billion years of time for life to get multi cellular.
Yes I know I'm being a bit chauvinistic of earth based life examples but it's the only example we've got.
None may recall this, but when it was thought that the Allan Hills 84001 meteor had Martian microbes on it, president Clinton had actually made a public announcement that alien life had been discovered. The public reaction was passe, to say the least and eventually people stopped talking about it, even before the findings were revoked.
That incident is always my #1 argument against alien conspiracy theorists. I firmly believe that if the government ever truly thought they found alien life they'd blab about it rather than try to keep it secret just so they could get their name in the history books.
I don't know if you have already covered this in preexistant Fermi Paradox videos, however (as I have yet to see all of them):
What is your opinion on the idea that planetary governments will (at some point) forbid space colonization (and force-abandon any existent colonies) in order to prevent the possibility of a colony being founded for the secret purpose of destroying the homeworld?
1) If we consider our modern day governments, they seem quite happy to say "someday humans will live among the stars" yet at the same time, not even the richest billionaires can so much as build a campsite upon Luna. (While this attitude has brought (SpaceX, etc.) into existence, (SpaceX, etc.) can be shut down with a presidential pen.)
2) If we consider our modern day (terrorists and any other such troublemakers), they seem quite happy to say "we will (genocidally) kill (the enemy) as soon as we have the advantage/opportunity."
3) If we consider the military advantage of a spacecraft (asteroid miner, etc.) launching asteroid(s) at the homeworld, one can't help but wonder if the first asteroid mining crew might be (closet terrorists, etc.)? (Even if it took 100 years post-manned asteroid mining for terrorists to get themselves into play, when they finally do, billions will burn).
4) The situation only gets worse when we consider how many political and cultural factions are presently waging war on each other Right Now. If any of them were able to easily build space colonies, they would do so for the purpose of weapons production; to gain the overwhelming advantage before their rivals do so and permanently defeat them. (Unfortunately, colonizing space is enormously expensive and easily sabotaged - it is too risky to try when your planetary borders could be on fire at any moment.)
5) I would say that this train of logic ends with planetary governments (the United Nations, etc.) saying "Even though we could mine asteroids, or colonize/terraform (Mars), we can't risk the possibility of (terrorists, etc) gaining control of (whatever) and using it to (fully annihilate) the (HomeWorld). Therefore, all offworld travel is forbidden - for reasons of public safety we won't let so much as an AI leave the atmosphere."
I bet that this is the biggest Filter of them all. It may even approach 100%.
What are your thoughts?
Did you already discuss this in a Fermi Paradox episode?
- If not, do you have enough material (and time) to fully explore it?
There has already been one attempt at that - the Moon Treaty of 1979. This was an attempt by the old Soviet Union (who helped create it but never signed it) to prevent US corporations from using any material from space for economic advantage, especially after the completely valid plans for space power satellites came out in the mid 70s. Of the space fairing nations, only India signed it (India has NOT ratified it), so it is not in force, but, yes, governments are afraid of the freedom a space fairing civilization will grant. So getting solidly into space before we have a functional world government is essential.
While they will use the threat of terrorists as an excuse, the reality is government service self selects for people who are autocratic (they want others to follow their orders), and who really hate the idea of some group being beyond their reach. We see this in small ways in the western republics (which include Japan and some other US influenced nations outside the west) - Exit taxes for emigrants, for example. In some countries, emigration is flat out prohibited, and/or currency cannot be taken out of the country (the old soviet empire, for example). So, yes, a terrorist could send an asteroid our way, and, for the conspiracy theorists out there, the government may do that as a false flag operation for propaganda. It would be safe enough, as the trajectory would be known early, and it could be broken up into small enough pieces to be destroyed in the atmosphere before it could do any harm.
OTOH, I doubt it would be significant filter, as a world government is unlikely to be a significant force as long as there isn't an exterior threat. Many (myself included) believe that the only valid purpose of government is to protect us from others forcing their will on us, so, if there is no "Other", why waste money on a government? An organization whose only purpose is to stop nations from attacking other nations is going to have all nations turn on it when it tries to prevent a "Post Scarcity" world from coming about - that would be an attack by the world government on the nations. That wouldn't be the "War between the States" (aka the US Civil War), that would be the "War of the States against the District of Columbia"! So it would be in the best interest of the World government to have a space fairing civilization, to solidify its hold on the member nations.
Some of this may be why we don't already have colonies in space. The (primarily US) government fears strengthening the UN into a real government, and therefore fears the risk of independent colonies more than it wants the riches of space.
So, at best, this would be a minor filter - half, or more, of all civilizations would get through this roadblock eventually.
Thank you, and congratulations, on this whole endeavor of yours!
Long may it prosper.
One response to the Fermi Paradox that I have never yet seen anyone propose is that, perhaps,
we have already detected radio signals from alien civilizations in our galaxy, many times over:
the so-called “strong candidate” signals, which have all the desired characteristics
except that they don’t repeat, or, rather, that WE don’t catch any followups
from the same region of sky.
Imagine that there were, in fact, numerous sites in our galaxy with a high-tech presence,
that were, indeed, chatting away with other such sites.
The senders would know in which direction to aim their signals,
but said directions would be continuously changing, because everything in our galaxy moves,
mostly in closed orbits, and none of those transmissions are aimed at us.
We simply catch a piece of transmission every time we happen to be in front of the intended recipient,
and we lose the signal as soon as the alignment breaks, alignment which may not happen again for many many years.
It surprises me that not even SETI spokespeople talk about this possibility, because,
at this point, there is surely enough data to conduct sophisticated statistical tests
to see if the fade-in, fade-out curves distribute in a way such as one should expect.
Have you folks ever asked someone like Seth Shostak about this?
On the topic fermi paradox, has anyone considered the answer might be radio telescopes aren't powerful enough to detect artificially made signals?
Recently astronomers detected the radio emission from an exoplanet for the first time. It was caused by interactions with what's believed to be a gas giant's atmosphere and it's parent star, who's magnetic field interacts with the atmosphere to create a very powerful beam of radio waves. That's the first time we've ever been able to detect radio waves from an exoplanet, and the emission source is orders of magnitude more powerful than all of our transmitters combined and required over 2,000 telescopes working across the globe to detect it. Also consider, we have trouble today, maintaining constant communication with the voyager probe, the furthest manmade object from earth and it's only located in the ort cloud.
So if we can't detect anything other than some of the most massive emissions in nature in other star systems, why would we be able to detect the cellphone traffic from that same star system?
About 1950, during the flying saucer era, the physicist Enrico Fermi realised that the Milky Way Galaxy is so old that you only need one spacefaring race to start spreading across our galaxy, and they will occupy all habitable worlds in a tiny fraction of the life of the galaxy. In conversation with friends he famously asked: ‘where is everybody?’ Why do we not meet aliens in space vehicles?
The article above considers this paradox from a different perspective. The authors assume that aliens are just as limited by the speed of light as we are, and can only travel at, say, 10% of the speed of light. This restricts each step in interstellar travel. Aliens may occupy a planet, but other stars are too far away to travel further. The authors regard all stars in the galaxy as moving effectively in a random fashion. Our nearest star is 4 light years away, but will be closer in a few thousand years, but further in the future, another star will be our nearest star. The authors assume that alien cultures do not last forever, so an alien culture that occupied Earth during the time of the dinosaurs may have died out for reasons unknown, and signs of their existence have been obliterated by the passage of deep time.
The authors point out that Pacific islands are an analogy for stars in our galaxy. Pitcairn Island was occupied by Polynesians until about the year 1400, then was unoccupied until the mutineers from the Royal Navy ship Bounty settled there late eighteenth century. Easter Island was also occupied, then unoccupied, then occupied again in modern times.
The authors suggest that there may well be space faring aliens, but they spread across the galaxy in a patchy manner.
It has the same issue as most stay-at-home civilization ideas, it works best if you also assume they kill themselves off or devolve or freeze into an almost perfectly controlled and unevolving society/organism or something after a while, because otherwise this "government" would have to somehow keep this policy up for billions of years. They would presumably want to to something about their sun dying, too, though that certainly be fixed by star-lifting, and even if not, it would theoretically be possible to just make sure the entire society just moved to another star system or somehow just hung around and built a Dyson Sphere around the white-dwarf or something.
Of course, you've already given quite a few ways for a home-world to be wiped out if anyone did break such a policy before it could be made safe, and if it happened early enough, the world-destroyers would probably die themselves, too.
Just a general post, Isaac Arthur talks a lot about how Dyson spheres would have to emit all the heat they absorb, but is it not posssible for them to be built to only emit it in one or a few directions? For one thing, that's basically the idea behind a Shkadov thruster, but it's also a good way of hiding, if there were any reason to, and it might even be possible to use such waste-heat to communicate or even push starships without producing much heat at all that would have to be radiated in all directions. Of course, maybe I have some woeful misunderstanding of thermodynamics, but it seems like all you would need would be some very cold outer layer with devices made from mirrors and/or superconductors that could somehow move the waste-heat from however thick of a Dyson sphere you wanted to create (since the Matrioshka brain concept would also apply to to just making almost indefinitely thick Dyson swarms if you could stand the low power-per person/volume/etc.) a direct it into some kind of beam going in one direction, maybe even a highly columnated beam or laser. The thing about this is that only people who happened to be in just the right direction would detect anything.
There still couldn't be very many Kardashev 3 civilizations hanging around in this scenario (assuming nothing better than Dyson spheres were found), since we'd expect to have noticed at least one half-way converted galaxy by now if there were a lot of them. Also, if to many of these things were being made, we ought to be able to notice that more mass was visible in the earlier universe (i.e., far from us) and that a large amount of it had converted into dark matter as time advanced to our time (i.e. close to us), and I don't think any such difference between near and far has been detected. Also, this would definitely fall under the candidate of MACHOS if they were just stars in galaxies, and I think there are reasons to doubt that as a primary explanation for dark matter (although that doesn't mean it couldn't explain some of it). I'm really not sure whether we are currently able to to detect entire separate galaxies of dark matter yet, and maybe that could explain some dark flows, but I feel like we probably can, and if we can and haven't, that's another sign that galaxies converted to Dyson spheres must be quite rare still. (Note I'm using dark matter in the strictly cosmological/astronomical sense. Most of dark matter would still need some other explanation in any realistic version of this scenario.)
I think it's a little silly to put too much store in the definitions of life currently used by biologists. Those are designed specifically to differentiate between naturally occuring (i.e. not artificially human-made) living and non-living things on Earth, not for xenobiology. The modern definition of life that I heard says that all life-forms have cells, but if we found aliens who didn't, we would still call them life. I think behavior is much more important, and anything that could be grey goo would be a lot more like life then it would be like fire or crystals or even viruses. Viruses are completely inert until they come across a living cell that they react with and take over. Grey goo would have to be something that acted independently, rather than being dependent on other life forms; it would have to react in very complex ways to stimuli in order to be able to break down so many different types of compounds, and it would definitely eat, emit "waste", use energy to do work, and reproduce itself (though it might not grow). Also, there's no reason something like grey goo wouldn't have something like cells; after all, cells are just a way to separate different solutions from each other and from the awkwardly large outside environment so that organisms can control chemical reactions better. Why wouldn't we copy a simple idea from nature for such a thing? (Well, it might not be necessary if the nanites were super small I guess, except that living cells are already made of lots and lots of tiny nanites working together, and cells are more efficient for them and allow them independence.)
Of course, no one's going to intentionally try to make canonical grey goo except maybe as a super-weapon, or perhaps as some kind of mining technology (which might do the construction with the material itself), but a lot of the same points could apply to other nanotechnology. It also should be noted that the most advanced nanotechnology humans will be making will probably be very much like the products of life for a long time, since we will probably continue to take advantage of the preexisting nanotechnology in living cells for a long time, just with more and more alterations and supplements. We already use genetically altered bacteria to synthesize drugs, and a lot of biochemistry has been using similar techniques for decades. In a way, genetic engineering is nanotechnology; we do use macromolecules we've taken from inside organisms to copy DNA, and specially altered ones to cut it and put it into cells.
The reason why no one cared, is because no one could make money off it and it did not affect anyone. Only a few people would ever care about reading a book on Martian microbes, so there was little to no money in it. And on the second point the Martian microbes didn't effect anyone’s daily lives.
It was recently announced that they have found microscopic life on Venus. This also did not find a strong response among the masses.
For the news of extraterrestrial life to be replicated, intelligent life is needed, not microbes.
Perhaps someday we will become a multi-planetary species. And most likely we will remain the only multi-planetary species in our galaxy for sure.
What was announced was the discovery of phosphine in the atmosphere of Venus. Phosphine is a bio-signature or something you would expect to observe on a planet which cradles life. However phosphine isn't produced exclusively by biological processes so its existence alone can't be considered conclusive evidence of life. Microscopic life hasn't been discovered on Venus. We don't have microscopes there. While the existence of phosphine in the atmosphere of Venus increases the chances that life exists on Venus those chances are still pretty low in my opinion.
I would say honestly that the chances for life on Venus are equal to greater than on Mars. At least, we may discover it there first, given that the life of Venus would be aerial, and that of Mars probably subterranean. People say that the recent doubt cast on the phosphine findings sets us back to there being no life on Venus. To those of us who are familiar with solar-system astrobiological prospects, we know that there are still indications that Venus may harbor simple life. The unknown UV absorbers in temperate zones and the micron-long particles shaped much like bacterium detected by the Venera missions are all tantalizing clues suggesting Cytherian life. Of course, one could take the intellectually lazy approach, and say that Occam's razor, especially in light of the alleged phosphine findings, says that these are all abiotic in origin. But we should keep all options open and send some probes over posthaste.