But, for decades, I’ve been reading reports of the discovery of evidence for the trappings of life elsewhere: water and organics and “habitable” exoplanets. These are valuable discoveries, but the tone of the reports suggest they imply life is about to turn up.

It’s worth remembering that there is not one single shred of evidence that life has ever existed anywhere in the observable universe but Earth. Moreover, no one has succeeded in hatching living matter from non living matter and we must honestly say we do not know how this process came about or the faintest estimate of how likely it is to occur (despite much speculation, some of which may turn out to be correct but equally may turn out to be dead wrong). The oft cited fact that life arose “quickly” after the formation of Earth has no bearing on the question.

When you immediately find strong pieces of circumstantial evidence the moment you acquire the tools to start looking for something, the correct conclusion to draw is not "we have yet to find a shred of evidence", but that further searching is likely to be highly worthwhile.

If Jeremy England’s hypothesis is true, then life shouldn’t be unique but rather inevitable, as life in general would be the way for matter to better dissipate heat, and better turn low entropy into high entropy.

In fact, if you watch what life is doing in terms of physics, then it’s obvious that all it does is consume low entropy (stored chemical energy, heat from heat baths), and dissipates it around very efficiently.

Even we, humans are more and more good at it: we take hydrocarbons chemical energy and turn it into work and heat. It’s not enough for us, we now consume energy stored in atomic bonds, and turn it into work and heat. We capture concentrated sunlight and also turn it into work and heat, etc.

Essentially, we are doing what we are supposed to do as a function of physical matter: we produce more entropy.

https://en.m.wikipedia.org/wiki/Entropy_and_life

Henry Adams first put it to print in the 1910s, and Schrödinger did a fine turn on it and wrote a whole book in the 40s.

The idea that life exists as the most efficient method to facilitate thermodynamic equilibrium is older than the neutron.

Any of the three results would have huge implications. And then rinse and repeat on Enceladus, Ganymede, Europa, and so on. And find a way to look at exoplanet atmospheres and chase stuff that comes in from outside the solar system. Even negative results will add enormously to our understanding.

https://www.cnet.com/science/sea-plankton-found-on-the-outer...

Our type of society is probably much much rarer because you need access to mineral and energy deposits to go through each technological phase. For example, because of all the mining we’ve done, if humanity were to disappear it’s highly likely the Earth would not sustain another technological society because all the “easy to get to” deposits of crucial metals & things like oil are gone and there’s no way to bootstrap a technological society (it’s possible other kinds of resources could be developed to build other kinds of technology so who knows).

I think based on our existing body of knowledge, life is likely extremely plentiful throughout the universe at one point in time or another. Some form of intelligent life is highly likely wherever we find any life that manages to stick around through bilions of years. A highly technological adept species of life though is highly likely an extreme rarity and a planet gets one shot at developing it. Whether any manages to escape their home planet remains an open question that likely only we will manage to answer over the next thousands of years if we make it that far.

Did I miss some big announcements? Where has anyone created life from inorganic material reactions in a highly controlled environment?

Serious question, not trolling.

Seems to me that would be an insta-Nobel.

Unless life originated directly at the formation of the universe and panspermia is how life got to this planet, the only logical explanation is that life somehow emerges from “nothing”. We don’t know the exact mechanism and it seems much more likely that life originates on a planet rather than in space & arriving at a planet. The “intelligent” panspermia explanation (i.e. aliens seeding life throughout the universe to preserve it) would still require an inorganic origin for life.

**Not my sub-field. Extremely complex models. Much is still unknown.

And if “out of nothing” is the baseline condition, the most likely explanation is that it happens where there’s a lot of energy to sustain it while not enough to kill it, which means planets at the boundary of thermal activity (since we need something more direct than photosynthesis which is a relatively complex capability that came late in Earth’s cycle as far as we know).

Trying to intuitively and logically reason about something with no answer in sight, all while assuming the truths of our era, may ultimately be pointless.

Our universe, logical though it may be, plays by its own rules, and many things will be simply irreconcilable until those rules are further elaborated on.

As an aside the big bang also does not really answer the prerequisite question of where the initial inorganic matter/energy came from. The idea there being some sort of a quantum fluctuation, which then begs the question of its origin. I suppose it's just turtles all the way down.

As I recall-though it's been many years-this was something of a premise in Farmer's Riverworld series. Once you've taken the first pass though historical mineral etc. resources, you don't really get a second pass.

Out of curiosity, if you reject religion, what other possibilities are there?

Nonuniform physics—call it colliding universes or whatever, but the processes that gave rise to life on Earth may not be possible anywhere in this universe now. Including labs on Earth!

I don't think religion is needed at all for this. I also don't think this has to be a common thing (after all, here on Earth it only happened once, but it's also possible that once life is widespread it makes it very difficult for emergent new forms of life to take off).

The articles I read assert that life began just 500 million to 1 billion years after formation of earth. 3.5-4.1 billion years ago with an earth age of 4.5 billion.

Are you suggesting that abiogenesis didn’t start on earth, but self-replicating molecules started evolving in earths protoplanetary disc?

Serious question, haven’t encountered that theory before. It’s kinda panspermia-lite.

Presumably like your parent, I believed this was a discussion about the probability that life has originated elsewhere in the galaxy / universe, independently of life on Earth.

It was pretty clear to people that there would be no life 750 metres inside the earth crust below another 700m of ocean: too hot, no light, pressure, bla, bla. - And plenty was found. Of course it's an easy counter "Still Earth, haha! Doesn't count". So yes, it's back to the point that whenever we have developped tech to go look, we have found "whatever the tech could find". Except - for now - TV serials radio waves. That's true. And bacteria on Mars. Yes it's a glib way to put it but it's not an unfair answer to that criticism.

Yeah, we know. So what then was the point of your post?

Also, at risk of incurring a flame, I'll gently point out that you are folding into this confusion and reinforcing it with your language: "likely precursors everywhere, habitable bodies" ... we absolutely do not know that these conditions are "likely" precursors, which is a statement about a probability we know nothing about and as for "habitable" we do not actually know anything about whether or not a body is habitable in the sense of likely to spontaneously form life.

sorry your life has created this crusade of rhetorically reminding people about the absence is evidence

We've just now learned how to analyze atmospheres of exoplants.

5 years ago, we couldn't see exoplanets smaller than jupiter.

A decade ago, we couldn't see exoplanets at all.

I find the entire idea that life could only exist on earth farcical. A lot of people in this thread don’t seem to understand that we can’t directly image many exoplanets to begin with and that we haven’t even been trying to find life on other planets and moons in our own solar system, it has in fact been suppressed every time credible circumstantial evidence of life is found (Viking lander experiments and methane on mars both come to mind)

I.e. before, "there had to be - some, somewhere" and now, "there is most likely all over the place".

But only after we really lowered our expectations in the first place. I have an old book, about the Viking Mars lander, describing the technical details, before the rover succesfully landed on mars. It is full of optimism and a strong expectation, that it will find evidence of at least bacteria.

And before we had strong telescopes and rockets, there was a strong expectation, that Mars has developed life.

We know, that bacteria can survive in stasis mode on asteroids - yet we have not found life on any other planet.

And we know at least one Jupiter satellite has water.

So that’s at least 4 bodies in the solar system that have water and all the bodies where we have successfully landed more than 1 rover have or had water (earth, moon, mars).

Every body where we could have discovered water, we have discovered water. Seems like bayes theorem indicates that water is also probably highly available in the universe.

If we can't promote abiogenesis in a lab our understanding is clearly limited, which is itself surprising. How many other processes in nature have we observed and not been able to replicate ourselves (or at least make progress towards replicating)?

I think it meant that even if life started itself accidentally by some unbelievably slim chance, this could happen somewhere else as well simply because the dice are rolled that often.

I think time is the factor here. When you take into account not only the size of the universe but also it‘s age, the chance that life started somewhere, somewhen and ended long ago could be larger than zero, even if we are not able to calculate it.

That might be true, but we have no basis the probability of how rare life is so we can't say it is. We may assume the probability is high enough that it happens often in trillions of chances, but if the probability is one in a quintillion then we're simply wrong.

Humans are incredibly bad at thinking about both probability and thinking about large numbers, so when we combine the two we're likely to be quite wrong.

But it’s also not like we’ve looked at enough of our galaxy to say it’s rare either. We just don’t know.

I’m curious how your epistemology is working here. It seems to me that this will also be true in the future if we have found life on a hundred other planets. There still won’t be a shred of evidence of life anywhere else, and we still won’t have the faintest estimate of how likely it is to occur, right?

Currently, we have only an upper limit on the probability and barely even that. All observations are consistent with a probability less that 10^-40, meaning it certainly wouldn’t happen a second time in the observable universe.

Something like 5,000 exoplanets have even been discovered. We can’t cross off many of those as certainly lacking life.

Why pick the lower limit? Existence of life on earth is extremely powerful evidence.

Ask yourself this, from how many planets in the universe would you be able to observe life on Earth?

And of course given how vast and indifferent to life the universe is, life would still be vanishingly rare in the universe. It's going to be always precious and a gem.

https://mars.nasa.gov/msr/

I think you have misread the tone. The article certainly has a tone of excitement throughout. But it’s excitement for further knowledge, in general.

Of the possibility of life showing up elsewhere, it says only this: “Scientists are still a long way from answering whether life could originate on Enceladus”

But I also think we are zeroing in on the inevitable outcome. The math of probability and the simple components to life make it seem pretty likely we’ll get there unless there is something more fundamental that hasn’t been seen yet.

We haven’t reproduced proto-life yet, but we also don’t have millions of years and a planet sized laboratory at our disposal.

Just want to comment on this point. The research in this field is pretty esoteric. It doesn't really benefit us to understand how this process came about (ie, there is little practical gain here, no medical advancements or otherwise), and moreover it requires a simulation which can estimate behavior over hundreds of millions of years. The usefulness of cracking the early earth/life creation part of our history is really not immediately clear, and thus research is limited.

That said, the Miller-Urey experiment (https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment) showed animo acids organizing over conditions similar to early earth, and a follow up experiment dubbed Planet Simulator (https://en.wikipedia.org/wiki/Planet_Simulator) was extended to show the organization of protocells as part of this early earth environment.

It seems only a matter of time before science can connect the dots along the rest of the hundreds of millions of years regarding this process to show the line between chemical young earth evolving to be biological.

As an aside, why do you think it is "important to remember" that we haven't found life or that we don't fully understand the process by which biology evolved from chemistry? Why exactly is it "important to remember" such things?

However, it does seem extremely rare and could be so rare that it doesn't exist in the observable universe (it's almost certainly not in our Local Bubble).

It is interesting to also think about the likelihood of "intelligent" life. Because while basic, simple organisms are bound to appear somewhere else considering the universe's vastness, the idea that they could develop this intelligence and self-awareness is another big leap that doesn't seem like it necessarily needs to happen wherever life is happening.

It is hard for me to believe that in the mind boggling vastness of space and time, we are the sole singularity in the history of the universe.

They figured no one would believe this, so they told people it was 29,002 feet

Sometimes things just are, regardless of what we expect.

If there isn't life on Enceladus this is still incredibly exciting because then it might make the perfect lab for us to put life and study how it evolves.

"The basic assumption of the model is that life should fundamentally and essentially have three properties: metabolism, self-replication, and a bilipid membrane.[3] The metabolic and replication functions together form an autocatalytic subsystem necessary for the basic functions of life, and a membrane encloses this subsystem to separate it from the surrounding environment. Therefore, any system having such properties may be regarded as alive, and it will be subjected to natural selection and contain a self-sustaining cellular information."

https://en.wikipedia.org/wiki/Chemoton

https://www.nationalgeographic.com/premium/article/he-may-ha...

Jews wouldn’t care either. Don’t know about Muslims, but it’s not threatening to the other Abrahamic religions

A definitive position on the existence of aliens is not part of the Catholic faith.

But, the church admits the possibility and church institutions have done some explorations about what the implications of such contact might be, and how Catholic doctrine might apply to different possibilities.

https://www.catholic.com/qa/whats-the-catholic-position-on-t...

Reminds me of the punch line to an amusing first-contact cartoon, one that makes the (unstated) previous line easy enough to guess: "Yeah, he comes by every couple of years. We gave him a nice box of chocolates when he first visited. What'd you guys do?"

Planet earth is 4.5 billion years old.

Life on earth started 3.7 billion years ago.

We sent our first radio wave just 125 years ago.

Probably life is not than unusual and we just don’t have a way to verify this (yet).

I know that there is a burning desire to think we’re special, but the truth of the matter is that we’re almost definitely not.

> The most commonly agreed-upon low probability event is abiogenesis

...which I read as saying that the most commonly agreed-upon reason we haven't found life anywhere else yet is because we _are_ special and abiogenesis is the rare event (the great filter).

All the various great filter theories are pretty fun reading.

I also think it’s a lot of pressure if it’s only us, so it’s easier to imagine we’re one of billions.

Honestly, honestly think it’s just us. Maybe not in the entire universe but in our local cluster.

Dude considering we're barely scratching the surface of the scratch on the scratch of the surface, I'd say this is really arrogant. We haven't found anything because our universe is a haystack and we're looking for the quark of a needle in that haystack. Perspective.

Sure, that's the base case. It's not "worth remembering" at all. It's as much worth remembering as the fact that my clothes are in the dryer right now.

If we're not early, if life isn't rare, and there are intelligent species [1], what might most of it look like?

I don't think most of them would match the techno signatures we're familiar with. Factories, gas emissions, etc. are an industrial age thing.

What if they're really smart? What does that look like? What kind of signals might we detect? What kinds of energy might they be harnessing?

Are there any good reads or papers that posit these things?

[1] I also imagine they've found a way to escape the limitations of intelligence and death, perhaps by becoming computers of some kind.

I am 100% convinced that this is in our future, not even very far out. Why put up with our flawed bodies if we don't have to? First we will probably replace parts of the body with something better until eventually the whole body has been replaced.

It's a scary thought, to be sure. That, no matter how close a computerized copy of me is to me; I'm still stuck in this body, in this own brain, and its inevitabilities.

I sometimes like to think that we ourselves are actually the memories of a distant descendant. Maybe it reversed the light cone and was able to replay everything with exacting precision. Maybe it's studying and musing over its humble beginnings. (It might get a laugh that we're communicating this to one another.)

It seems like a long time since there have been any really game-changing breakthroughs in theoretical physics. I'd be a fool to say that that means that there aren't any more to be had, but it does seem more like we're just sort of fiddling around with a few refinements and there might not be anything huge left. As you say, maybe a greater intelligence than what we've got can figure it out, but that does go back to Fermi - if they could do amazing things like enclose a star or travel interstellar distances, then why haven't we seen them?

What if it's all just protons, neutrons, and electrons (and some other less important particles presumably) plus a bunch of energy out there? Would a super-intelligence really be interested in seeing more of them?

E.g. snowpack melt -> mountain stream -> waterfall

A waterfall is a vastly simpler system than a living organism, but I wouldn’t be surprised if the origin of life has a flavor similar to waterfall formation.

I like the idea that all phenomena we observe are emergent in a similar way.

Hydrogen cyanide, acetylene, propylene, ethane, propene. There's bacteria that live off acetylene (though surely abiotic processes too). I suspect this indicates plenty of energy and complex chemistry on Enceladus. Some of those compounds are energetic while others (I think?) are combustion bi-products. Otherwise, I wonder when/if we'll ever see oxygen (O2) confirmed in a study like this? I realize it's highly/easily bound up in reactions, but what a finding that'd be. They list a probability of 0.64 (aka 64%) chance of O2 here. Imagining a surface of water ice and near vacuum atmosphere, I suspect any free oxygen would be very difficult to detect. But they also see co2 so maybe any oxygen is quickly used up? source: https://www.nature.com/articles/s41550-023-02160-0.epdf

I imagine like early earth, if there are organisms they are following an anoxic pathway

i.e. I would expect "enthusiasm" to look like discussions on building the infrastructure for multiple missions out there. Communications way points, some basic resource stuff, etc. Stuff to make getting things in that system more robust and timely.

Edit: Maybe experiment/do the laser propulsion tech. "Lighthouses" at critical points.

Society, religion, mass institutions would be forced to reconcile with this fact.

I don't think it's necessarily about money.

The only one I know well is evangelical Christianity, having been raised in it.

I've read through the Protestant Bible several times, and I'm not aware of anything in it that changes meaningfully if there's other life forms in the universe.