Amino acids found in asteroid samples collected by Japan's Hayabusa2 probe(english.kyodonews.net)
english.kyodonews.net
Amino acids found in asteroid samples collected by Japan's Hayabusa2 probe
https://english.kyodonews.net/news/2022/06/9a7dbced6c3a-amino-acids-found-in-asteroid-samples-collected-by-hayabusa2-probe.html
175 comments
Difficult question, but there's an analogous question for 'carbon-based' life - are there non-carbon based life? The answer is likely "no", simply because the number of molecules based on carbon is many orders of magnitude larger than for the next largest (sulfur).
Similarly for DNA: there are other polymers that have some of the same properties, but not to the same extent. Specifically, the ability to store information is so great in DNA. Most polymers are either regular like (-CH2-)n or random (eg lignin) while DNA (and RNA) are 'structured random', for lack of a better term.
Add to this the ability to 'unzip' double-stranded DNA into two copyable halves, its great stability, and ability to be coiled up. Like water - which is another example of something with an abundance of useful features - it's very hard to see any rival molecule that could do as many things.
Of course, you could just argue that we have not discovered or invented such a molecule yet. People have tried to make alternate compounds, and there are - as one of the other repliers pointed out - many variations in biology such as alternate nucleobases, or things like double-stranded RNA viruses, etc.
More generally, you could of course imagine distributing the properties of DNA across multiple molecules or molecular systems. That suffers from Occam's razor a little, but cannot be ruled out, I suppose.
Similarly for DNA: there are other polymers that have some of the same properties, but not to the same extent. Specifically, the ability to store information is so great in DNA. Most polymers are either regular like (-CH2-)n or random (eg lignin) while DNA (and RNA) are 'structured random', for lack of a better term.
Add to this the ability to 'unzip' double-stranded DNA into two copyable halves, its great stability, and ability to be coiled up. Like water - which is another example of something with an abundance of useful features - it's very hard to see any rival molecule that could do as many things.
Of course, you could just argue that we have not discovered or invented such a molecule yet. People have tried to make alternate compounds, and there are - as one of the other repliers pointed out - many variations in biology such as alternate nucleobases, or things like double-stranded RNA viruses, etc.
More generally, you could of course imagine distributing the properties of DNA across multiple molecules or molecular systems. That suffers from Occam's razor a little, but cannot be ruled out, I suppose.
Nobody is sure, but if you allow me to guess ...
Perhaps DNA and RNA are inevitable, or at least they are the easiest solution for they problem they solve. I guess even the same sugars and some nucleotides. The only variation on Earth is that some parts of the DNA are methylated, but it can be added and removed. There are some weird bases in the RNA for very special task, but my guess is that they will use the same main bases. I'd not be surprised if alien has DNA and RNA that is chemically identical to us (but in other order).
Even proteins are probably inevitable. Here there is more wiggling room. We use 20 amino acids, but there are like 5 more weird amino acids that are mostly modifications of usual amino acids and are made after the protein is formed. For example collagen uses a lot of proline that is a normal amino acid, and also hidroxyproline that is a modification of proline made during the creation of collagen https://en.wikipedia.org/wiki/Collagen#Synthesis I guess that the list of amino acids used by aliens will be slightly different. Perhaps between 15 and 25 instead of the 20 we use. Perhaps also some replacements. But perhaps the list has some special property we have not discovered yet. I don't expect a smoking gun here to determine if aliens are unrelated to us.
The most interesting part is the translation from DNA/mRNA to proteins https://en.wikipedia.org/wiki/Genetic_code It's a translation from the 64 combinations of 3 bases of DNA/RNA to amino acids. It's almost blocked, so there are 16 blocks with 4 options in each one. But some blocks have small changes. We know like 20 versions of the small changes. The 20 versions are very similar, they are not very different. So it's possible to make changes in this translation table. The most interesting part are the 16 blocks. As far as we know the elections it arbitrary, like a frozen random initial election that was inherited by all of living things on Earth.
So the first thing to check in an alien life is if they translate in the 16 blocks the same amino acid that we translate. I'd be very surprised if this is the case. My guess is that it's almost random, and any election is fine, and each independent alien life will have a very different initial random election.
Perhaps DNA and RNA are inevitable, or at least they are the easiest solution for they problem they solve. I guess even the same sugars and some nucleotides. The only variation on Earth is that some parts of the DNA are methylated, but it can be added and removed. There are some weird bases in the RNA for very special task, but my guess is that they will use the same main bases. I'd not be surprised if alien has DNA and RNA that is chemically identical to us (but in other order).
Even proteins are probably inevitable. Here there is more wiggling room. We use 20 amino acids, but there are like 5 more weird amino acids that are mostly modifications of usual amino acids and are made after the protein is formed. For example collagen uses a lot of proline that is a normal amino acid, and also hidroxyproline that is a modification of proline made during the creation of collagen https://en.wikipedia.org/wiki/Collagen#Synthesis I guess that the list of amino acids used by aliens will be slightly different. Perhaps between 15 and 25 instead of the 20 we use. Perhaps also some replacements. But perhaps the list has some special property we have not discovered yet. I don't expect a smoking gun here to determine if aliens are unrelated to us.
The most interesting part is the translation from DNA/mRNA to proteins https://en.wikipedia.org/wiki/Genetic_code It's a translation from the 64 combinations of 3 bases of DNA/RNA to amino acids. It's almost blocked, so there are 16 blocks with 4 options in each one. But some blocks have small changes. We know like 20 versions of the small changes. The 20 versions are very similar, they are not very different. So it's possible to make changes in this translation table. The most interesting part are the 16 blocks. As far as we know the elections it arbitrary, like a frozen random initial election that was inherited by all of living things on Earth.
So the first thing to check in an alien life is if they translate in the 16 blocks the same amino acid that we translate. I'd be very surprised if this is the case. My guess is that it's almost random, and any election is fine, and each independent alien life will have a very different initial random election.
There are so many examples of convergent evolution [0] here on Earth that it seems reasonable to speculate that many of the most useful compounds for life would evolve similarly many times over a large number of trials/planets.
Since we don't have access to such data, some metrics that seem useful for speculation about a property are: - How often it has evolved independently on Earth - How fast it evolved and remained dominant
That being said, there is a potential positive feedback loop going on, where most life depends on or benefits from compounds it gets from other life. Because there is an abundance of certain types of amino acids, we could hypothetically be stuck in a less optimal overall biosphere state, whereas a more fit biosphere might exist with a different composition of amino acids or other building blocks that played the same role. I'm defining fitness of the biosphere as the amount of energy from the sun that life harnesses for work.
[0] https://en.wikipedia.org/wiki/Convergent_evolution
Since we don't have access to such data, some metrics that seem useful for speculation about a property are: - How often it has evolved independently on Earth - How fast it evolved and remained dominant
That being said, there is a potential positive feedback loop going on, where most life depends on or benefits from compounds it gets from other life. Because there is an abundance of certain types of amino acids, we could hypothetically be stuck in a less optimal overall biosphere state, whereas a more fit biosphere might exist with a different composition of amino acids or other building blocks that played the same role. I'm defining fitness of the biosphere as the amount of energy from the sun that life harnesses for work.
[0] https://en.wikipedia.org/wiki/Convergent_evolution
> There are so many examples of convergent evolution [0] here on Earth that it seems reasonable to speculate that many of the most useful compounds for life would evolve similarly many times over a large number of trials/planets.
Examples of convergent evolution of the most useful compunds for life on Earth. It makes sense that in a unified environment (of Earth) there is a tendency to evolve similar mechanisms to survive - on Earth.
But we just don't know what kind of other chemical environments might be out there, in the virtually infinite cosmos. As beings of Earth-based life we fail to imagine any other possibility. This is a failing of our own understanding, not of chemistry to produce life. We just don't know, so we can't really even begin to guess. All we know is, our own backyard looks pretty dead except for us.
Examples of convergent evolution of the most useful compunds for life on Earth. It makes sense that in a unified environment (of Earth) there is a tendency to evolve similar mechanisms to survive - on Earth.
But we just don't know what kind of other chemical environments might be out there, in the virtually infinite cosmos. As beings of Earth-based life we fail to imagine any other possibility. This is a failing of our own understanding, not of chemistry to produce life. We just don't know, so we can't really even begin to guess. All we know is, our own backyard looks pretty dead except for us.
We can actually get a pretty good idea from looking at the spectral emissions, at least which environments are likely to be more common.
On ptable.com [0] you can compare the abundance of elements in a human to the abundance on Earth, meteors, the solar system, and the universe. It seems like despite an abundance of aluminum, silicon, iron, and titanium, relatively trace amounts are found in humans (a typical animal), and most heavier elements are not needed at all and are actively toxic.
The more versatile, modular, lightweight elements are very highly represented in humans. There's a reason organic chemistry is its own field -- those "more elementary" elements are simply more unique than heavier ones. At the top of the periodic table where the nuclei have small masses and closer orbitals, the relative impact of unfilled orbitals is much more significant. The standard reduction potential of Lithium (element no. 3) is a prime example of why it is so uniquely dominant for battery chemistry.
I agree with you that our universe is a big place and a lot could happen, but my point is that attractor states exist and I would expect orders of magnitude more life to be based on organic chemistry, and probably even similar amino acids / a DNA double helix than not. Those lighter elements also tend to be more common elements throughout the universe, so the amount of planets where life with some inferior chemistry based on germanium (everything would be much heavier for the same reactivity patterns as an organic compound) would be limited to planets where there is a ton of germanium and not much carbon or silicon, which would be very rare (although it would be awesome to see what would happen!).
[0] https://ptable.com/?lang=en#Properties/Abundance/Human
On ptable.com [0] you can compare the abundance of elements in a human to the abundance on Earth, meteors, the solar system, and the universe. It seems like despite an abundance of aluminum, silicon, iron, and titanium, relatively trace amounts are found in humans (a typical animal), and most heavier elements are not needed at all and are actively toxic.
The more versatile, modular, lightweight elements are very highly represented in humans. There's a reason organic chemistry is its own field -- those "more elementary" elements are simply more unique than heavier ones. At the top of the periodic table where the nuclei have small masses and closer orbitals, the relative impact of unfilled orbitals is much more significant. The standard reduction potential of Lithium (element no. 3) is a prime example of why it is so uniquely dominant for battery chemistry.
I agree with you that our universe is a big place and a lot could happen, but my point is that attractor states exist and I would expect orders of magnitude more life to be based on organic chemistry, and probably even similar amino acids / a DNA double helix than not. Those lighter elements also tend to be more common elements throughout the universe, so the amount of planets where life with some inferior chemistry based on germanium (everything would be much heavier for the same reactivity patterns as an organic compound) would be limited to planets where there is a ton of germanium and not much carbon or silicon, which would be very rare (although it would be awesome to see what would happen!).
[0] https://ptable.com/?lang=en#Properties/Abundance/Human
Seems very quantity-oriented. Maybe having lots of a thing is required for life to evolve from it, but again we have a sample size of 1. Maybe there is a quality-based form of life where what matters is not how much stuff there is to evolve from, but having a specific variety of different elements in the right conditions. Maybe all it takes is a handful of atoms in a particular unimaginable environment.
I'm by no means an expert on this subject.
There are many different forms that RNA takes, and some of those forms are double-stranded, but differ from DNA in certain key ways. There are even "non-canonical" forms of DNA which exist whose nucleobases differ from the traditional four bases found in most DNA.
Thus, you're premise that all DNA on Earth is "chemically identical" is flawed. But, if you expand the scope of your a bit, then the answer is a little more satisfying.
There are many different forms that RNA takes, and some of those forms are double-stranded, but differ from DNA in certain key ways. There are even "non-canonical" forms of DNA which exist whose nucleobases differ from the traditional four bases found in most DNA.
Thus, you're premise that all DNA on Earth is "chemically identical" is flawed. But, if you expand the scope of your a bit, then the answer is a little more satisfying.
Convergent evolution has been observed many times on Earth. I think it's plausible that a similar process of evolution may be possible for DNA.
https://en.wikipedia.org/wiki/Convergent_evolution
https://en.wikipedia.org/wiki/Convergent_evolution
It's a good question. It seems there are meany sources, including production on earth[1] and in space. It seems a lot of commonly available chemicals in space if hit with light or electricity will generate them. The open question has been what does it take to generate RNA/DNA. There has been suggestion that RNA would be unlikely to form in open, active water like found on early Earth. However, Mars would have had shallow oceans with large amount of shore area for chemicals to combine in quiet.
The Panspermia theory is that RNA/DNA formed there and was ejected by asteroid hits to Earth. Support for that theory is that life appears to have formed within a few hundred million years of it being possible on Earth, which seems far too short of a time for RNA/DNA to form spontaneously in an ocean Earth.
If this is all true, life may be a fluke and requiring a rather stable set of environments to work. All of this is hard to know with a sample size of one, though.
[1] https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment
The Panspermia theory is that RNA/DNA formed there and was ejected by asteroid hits to Earth. Support for that theory is that life appears to have formed within a few hundred million years of it being possible on Earth, which seems far too short of a time for RNA/DNA to form spontaneously in an ocean Earth.
If this is all true, life may be a fluke and requiring a rather stable set of environments to work. All of this is hard to know with a sample size of one, though.
[1] https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment
Just recently on HN was RNA forms on basalt lava glass in the presence of nucleoside triphosphates, https://news.ycombinator.com/item?id=31628832 . Not a complete answer though, as I don't think we know if there where nucleoside triphosphates around (here, or on Mars for that matter).
Probably not chemically identical, but similar. Different nucleotides and protein sequences, but you'd certainly see alot of the same structures (alpha helix, beta pleated sheet, etc.) and things like methylation. I would expect this based on the fact that DNA is incredibly information dense, so it would be surprising if the universe had completely novel ways to optimize for that problem.
There’s a great Lex Fridman podcast related to this, about “Assembly Theory”, by Lee Cronin. I thought it was fascinating.
Youtube: https://youtu.be/ZecQ64l-gKM
Spotify: https://open.spotify.com/episode/4U3teONvRzNh32qqtX6X2w?si=5...
Youtube: https://youtu.be/ZecQ64l-gKM
Spotify: https://open.spotify.com/episode/4U3teONvRzNh32qqtX6X2w?si=5...
In https://chemrxiv.org/engage/chemrxiv/article-details/60c7588..., they find the common nucleobases are found earlier in enumeration, so you might expect most life use it
"DNA" itself is so complicated that there are different conformations [1] of the winding, sense, rise, pucker, etc.
There are an unlimited number of different bases that could be used to encode information, too!
[1] https://en.wikipedia.org/wiki/A-DNA
There are an unlimited number of different bases that could be used to encode information, too!
[1] https://en.wikipedia.org/wiki/A-DNA
If this was the case, then here on earth would we see more and more DNA appearing that doesn't follow an expected evolution tree? but then also our current DNA creatures would/could absorb/eat them before they are allowed to adapt to pressure in the surrounding environment?
Not the first time they found amino acids on a asteroid, but great news nonetheless.
For example the Murchison Meteorite had over 70 different aminoacids found on it while parts of the meteorite being dated as old as 7b years.
https://en.wikipedia.org/wiki/Murchison_meteorite#Nucleobase...
https://en.wikipedia.org/wiki/Murchison_meteorite#Nucleobase...
The article mentions this already (that meteorites on earth have been found with amino acids). The important difference here is the in the Murchison case, it was already exposed to Earth's atmosphere and environment, so you couldn't be sure where the amino acids came from.
Yes, but the fact that thirty three of these Murchison amino acids are 'unknown in natural materials other than carbonaceous chondrites' gives pause for thought.
https://pubmed.ncbi.nlm.nih.gov/11542462/
https://pubmed.ncbi.nlm.nih.gov/11542462/
What does this mean exactly? Or what could it mean?
That meteor is either proof of pre-Earth life, since those amino acids aren’t known to exist in rock otherwise or proof that the relevant amino acids can be created by an abiotic process. If you don’t want to believe the meteor has been contaminated since it hit the Earth.
Can amino acids survive the intense heat on entry into the atmosphere?
Apparently it's thought that meteorites hitting the ground freeze water around them after a bit. They get heated up, but it's pretty short, so the bulk of it is "space temperature" only the surface is heating. And a lot of the stuff that heats up is ablated. (depending on size)
Unless the stuff is on the surface of the meteorite it's probably fine.
Unless the stuff is on the surface of the meteorite it's probably fine.
Sometimes!
> For example the Murchison Meteorite had over 70 different aminoacids found on it
In it. Not "on it". A very important distinction. You'd expect to find all kinds of bio stuff on pretty much any solid object.
In it. Not "on it". A very important distinction. You'd expect to find all kinds of bio stuff on pretty much any solid object.
Finding amino acids on an asteroid confirms something we already knew. They can be available without showing evidence of life.
The real mystery thus remains life itself. The fact that on Earth it used amino acids to express itself doesn't mean that it is necessarily limited to that single choice. It also doesn't mean that the same process would repeat in a different world, even if all the preconditions were met, i.e. the necessary for the presence of life as we can recognize it.
For all our understanding of (earthly) biology, and the tools at our disposal that we use to decide that something is alive, we still don't really know what life is, or how it begins. On another world it might as well kickstart the magic with a different medium than amino acids (e.g. more crystalline structures, some energy forms such as light or electricity, etc), with entirely different rules of replication and sustenance. It would probably make life look different to us, potentially not recognizable or even detectable.
Heck, it could happen right here, under our nose and we'd be none the wiser.
The real mystery thus remains life itself. The fact that on Earth it used amino acids to express itself doesn't mean that it is necessarily limited to that single choice. It also doesn't mean that the same process would repeat in a different world, even if all the preconditions were met, i.e. the necessary for the presence of life as we can recognize it.
For all our understanding of (earthly) biology, and the tools at our disposal that we use to decide that something is alive, we still don't really know what life is, or how it begins. On another world it might as well kickstart the magic with a different medium than amino acids (e.g. more crystalline structures, some energy forms such as light or electricity, etc), with entirely different rules of replication and sustenance. It would probably make life look different to us, potentially not recognizable or even detectable.
Heck, it could happen right here, under our nose and we'd be none the wiser.
I've always wondered about this too, but kind of landed on something like this:
Sure, there might be (and probably is) life out there that falls so far outside our definition of "life" that we would never detect it. If it's undetectable, and maybe even incomprehensible, to us, then what's the point in even thinking about it in the context of a "search for life"? What we really mean by the question "Is there life out there?" is "Is there life out there that's similar enough to the life we see on Earth that we could recognize it as such and interact with it?"
I don't have a good way to phrase what I'm getting at without sounding dismissive - I do think it's interesting to think about other forms of "life", but it seems almost philosophical at that point and not scientific.
Sure, there might be (and probably is) life out there that falls so far outside our definition of "life" that we would never detect it. If it's undetectable, and maybe even incomprehensible, to us, then what's the point in even thinking about it in the context of a "search for life"? What we really mean by the question "Is there life out there?" is "Is there life out there that's similar enough to the life we see on Earth that we could recognize it as such and interact with it?"
I don't have a good way to phrase what I'm getting at without sounding dismissive - I do think it's interesting to think about other forms of "life", but it seems almost philosophical at that point and not scientific.
Honestly I think similarity is a bit of a red herring. The most interesting question is whether there are other beings we can communicate with in any sense of the word, so that we may learn from each other. For a somewhat trivial example, if we found robots on another planet, we would not consider them "life", but it would nevertheless be an incredibly important discovery.
On the other hand, it's of course imaginable that there are beings that we would in principle consider intelligent agents, but who exist in a way that in practice we have no hope of recognizing as such. Again to pick a somewhat trivial example, if galaxies were in fact intelligent beings that take billions of years to form a single thought, we may both in principle be very interested in communicating with each other, but in practice could never even hope to recognize each other as sentient beings, because of the intense difference in time scale.
On the other hand, it's of course imaginable that there are beings that we would in principle consider intelligent agents, but who exist in a way that in practice we have no hope of recognizing as such. Again to pick a somewhat trivial example, if galaxies were in fact intelligent beings that take billions of years to form a single thought, we may both in principle be very interested in communicating with each other, but in practice could never even hope to recognize each other as sentient beings, because of the intense difference in time scale.
> Honestly I think similarity is a bit of a red herring. The most interesting question is whether there are other beings we can communicate with in any sense of the word
Much the same thing, as I read it: I think the GP meant "similar" in the sense of "alike us in that it even does 'communicate' in any sense in the first place".
Much the same thing, as I read it: I think the GP meant "similar" in the sense of "alike us in that it even does 'communicate' in any sense in the first place".
There are certain questions that are so stubbornly elusive to science (as the study of nature), that they should feel by now to belong to the realm of philosophy (e.g matter, consciousness, mathematics, an infinite universe). The study of life itself, not its manifestation in nature, has so far displayed all those fleeting qualities.
But I guess science is stubborn too, so let's see where we get.
But I guess science is stubborn too, so let's see where we get.
See the 'God of the Gaps' argument. At any given time, there has been a list of things considered to be the rightful domain of philosophers and theologians rather than logical positivists. So far, the list has only gotten smaller.
The possibility of extremely exotic new types of life has to be a given, but with Earthlike starting conditions turning out to be relatively prevalent and the robustness of convergent evolution (not to mention the possibility of some kind of panspermia event) there's just as good of an argument to be prepared for extra-terrestrial life to be similar to us in shocking ways.
> "Proving amino acids exist in the subsurface of asteroids increases the likelihood that the compounds arrived on Earth from space," he said.
Are we sure it doesn't just mean the compounds were already sitting on Earth for the same reason they're sitting on the asteroid? I guess maybe if literally all of them were cooked to death in the Hadean and had to be refreshed from space, but then how do they avoid being cooked to death in asteroid impacts?
Are we sure it doesn't just mean the compounds were already sitting on Earth for the same reason they're sitting on the asteroid? I guess maybe if literally all of them were cooked to death in the Hadean and had to be refreshed from space, but then how do they avoid being cooked to death in asteroid impacts?
I belief the latest theories state thet life started already before the end of the Hadean. From that I conclude that cooking to death occurs less than one might think. 4.1B years ago while the hadean ended 4B years.
https://www.science.org/content/article/scientists-may-have-...
https://www.science.org/content/article/scientists-may-have-...
I think I was just using "Hadean" incorrectly to refer to "when the Earth was still basically molten". Thinking/reading about it some more I'm not sure that was ever enough of a thing to actually cook off organic molecules (but if it was, yeah it definitely ended early enough for life to start really dang early).
We again return to the rabbit hole that is the Fermi Paradox [1]. In short: there are so many stars and planets and we've had billions of years. Why aren't ther emore signs of technological life?
A core idea of this is that there are various filters that separate a new planet from one hosting spacefaring life. There are lot of these filters proposed. One category is the Great Filter. These are where very few lifeforms are expected to pass.
So what we're talking about here is an early filter where a planet forms in a relatively stable and suitable star system and single cellular life forms. Based on our own understanding of biochemistry, that pretty much requires amino acids. Now there might be other forms of life out there but they're all theoretical. We have one which is real (ie ours).
We've had a lot of experimentals that show that amino acids can form in deep space on icy bodies. What we have here is direct evidence from an essentially random asteroid that it has amino acids on it. We can and will speculate as to the origins of these. Did they form on the asteroid? Elsewhere? When?
You can't obviously draw too many conclusions from a single data point but to suggest we got extremely lucky to find the a super rare asteroid with amino acids on it stretches incredulity.
So the conditions that lead to life similar to ours forming being relatively common only gets stronger. This is similar to the number of expoplanets we've found. We've shown that planetary systems are exceedingly common, which was something we could only speculate about a mere 40 years ago.
More planets, more conditions for life forming. This means more species are likely getting filtered further down the chain.
[1]: https://en.wikipedia.org/wiki/Fermi_paradox
A core idea of this is that there are various filters that separate a new planet from one hosting spacefaring life. There are lot of these filters proposed. One category is the Great Filter. These are where very few lifeforms are expected to pass.
So what we're talking about here is an early filter where a planet forms in a relatively stable and suitable star system and single cellular life forms. Based on our own understanding of biochemistry, that pretty much requires amino acids. Now there might be other forms of life out there but they're all theoretical. We have one which is real (ie ours).
We've had a lot of experimentals that show that amino acids can form in deep space on icy bodies. What we have here is direct evidence from an essentially random asteroid that it has amino acids on it. We can and will speculate as to the origins of these. Did they form on the asteroid? Elsewhere? When?
You can't obviously draw too many conclusions from a single data point but to suggest we got extremely lucky to find the a super rare asteroid with amino acids on it stretches incredulity.
So the conditions that lead to life similar to ours forming being relatively common only gets stronger. This is similar to the number of expoplanets we've found. We've shown that planetary systems are exceedingly common, which was something we could only speculate about a mere 40 years ago.
More planets, more conditions for life forming. This means more species are likely getting filtered further down the chain.
[1]: https://en.wikipedia.org/wiki/Fermi_paradox
One thing that always struck me about humanlike intelligence on Earth is how quickly it came about.
The dinosaurs had 180 million years or so to get it right, and we find no evidence of so much as a simple tool. Were they no smarter that crows? All that time?
And Homo has been around, what, 2 million years? In just 2 million years we've gone from basically zero tech to outer-freakin-space.
Arguably, we've gone from nothing to outer-freakin-space in the last 6000 years, starting around the Bronze Age. That's astoundingly quick given how long life has existed on Earth.
So it seems like as the dice were being thrown around we were just waiting for that magic run of all sixes that enabled us to, in the blink of an eye, become spacefaring.
What was it? (Opposable thumbs? Language? War? Big brains? Etc?) And how likely are these things to happen in a magical combination? It took its sweet time here. Did we get lucky it only took 4 billion years? Or unlucky it took that long at all?
But it never happened to the hapless dinos. Which is too bad, because space dinosaurs would be _awesome_.
[Meme of dinosaurs looking up at the asteroid falling from the sky and one saying, "Oh fuck! The economy!"]
The dinosaurs had 180 million years or so to get it right, and we find no evidence of so much as a simple tool. Were they no smarter that crows? All that time?
And Homo has been around, what, 2 million years? In just 2 million years we've gone from basically zero tech to outer-freakin-space.
Arguably, we've gone from nothing to outer-freakin-space in the last 6000 years, starting around the Bronze Age. That's astoundingly quick given how long life has existed on Earth.
So it seems like as the dice were being thrown around we were just waiting for that magic run of all sixes that enabled us to, in the blink of an eye, become spacefaring.
What was it? (Opposable thumbs? Language? War? Big brains? Etc?) And how likely are these things to happen in a magical combination? It took its sweet time here. Did we get lucky it only took 4 billion years? Or unlucky it took that long at all?
But it never happened to the hapless dinos. Which is too bad, because space dinosaurs would be _awesome_.
[Meme of dinosaurs looking up at the asteroid falling from the sky and one saying, "Oh fuck! The economy!"]
> What was it?
My lacking-evidence and very unverified theory is that it's something like bicameral mind theory. It wasn't until we developed a complex enough brain to have self metacognition that we started to take off as a species.
My lacking-evidence and very unverified theory is that it's something like bicameral mind theory. It wasn't until we developed a complex enough brain to have self metacognition that we started to take off as a species.
My lacking-evidence theory is that this primarily evolved in mammals due to the requirements of child care imposed by mammalian birth.
Is it possible that this presupposes the utility of inteligence for survival? It's an easy thing to assume, but a decent argument could be made for intelligence in sufficient quantity actually running counter to the fitness of a species.
I would assume our style of intelligence isn't any kind of "goal", it just happened.
I would assume our style of intelligence isn't any kind of "goal", it just happened.
How do you contend with the fact that humans dominate every ecosystem we enter? We don't just become the apex predator, we annihilate them all, entirely. Additionally, we find incredibly complex use cases for resources they ignored which increase wealth and prosperity across our civilization. To me, that suggests human intelligence is the most powerful force of survival in the known universe.
Annihilating the eco system we life in demonstrates that our intelligence isn't that good, and doesn't seem to showcase it's a powerful force for long-term survival.
Of course there are plenty of metrics by which other species exceed humans, even some cognitive ones, and human intelligence in the end might just mean quick world domination followed by a quicker extinction, but the power and planetary supremacy that it endowed humans with in a cosmic blink of an eye is undeniable. No other species even comes close.
Ecosystem-destroying catastrophic behavior isn't unique to humans, either. We are the only known form of life that can bring it about on a global scale, reason about it, and have the potential to consciously avert it.
Ecosystem-destroying catastrophic behavior isn't unique to humans, either. We are the only known form of life that can bring it about on a global scale, reason about it, and have the potential to consciously avert it.
Destroying and consuming everything on earth for short term comfort and gains isn't what I'd call the smartest move.
It's like burning your bed in winter because you're cold, it sure feels food for a few minutes but then you start breathing in the fumes and wondering where you'll sleep tomorrow
It's like burning your bed in winter because you're cold, it sure feels food for a few minutes but then you start breathing in the fumes and wondering where you'll sleep tomorrow
The trick for the species is to get off planet to the infinite resources in the wider galaxy, in which case it isn't short term gains. It might suck for individuals and the ecosystems destroyed.
We can't even live sustainably on the planet we evolved to thrive on for millions of years and people think we'll just terraform a whole or planet/solar system/galaxy...
Living sustainably has little to do with expansion of the species (and population, pretty much by definition). Almost the opposite. Maybe the solution to Fermi's Paradox being discussed is other species do become fully sustainable and thus never spread. Leaving us with the opportunity to devour the galaxy like a cancer.
Maybe intelligent dinosaurs had a very strong "no littering" policy.
Silurian hypothesis is very intriguing.
https://en.wikipedia.org/wiki/Silurian_hypothesis
https://en.wikipedia.org/wiki/Silurian_hypothesis
I've always wondered about this. Let's say civilization evolved a billion years ago on Mars or Venus to the level we are now. Would we ever be able to detect it? If they put up satellites, could some still be orbiting, or would they all have degraded by now? What if they really wanted to leave some sign they were there? What could they do? Venus would be really hard unless satellites work. But maybe Mars?
I imagine there would be residue of artificially created nuclear materials that would still be detectable a billion years later. Some half lives are measured in sextillion/quintillion years.
I don’t have a reference handy but I remember reading there is a candidate period around 55 million years ago. The temperature rose rapidly and there are elevated heavy metals and isotopes in the crust from that time period.
Remember that the crows are dinosaurs in a sense. The dinosaurs are still in the game; don't count them out yet.
Exponential growth [1]
We went from the invention of radio in 1895 to a moon landing within 74 years. And 53 years later we have tech that is vastly superior to what we had in 1969.
[1] https://en.wikipedia.org/wiki/Exponential_growth
We went from the invention of radio in 1895 to a moon landing within 74 years. And 53 years later we have tech that is vastly superior to what we had in 1969.
[1] https://en.wikipedia.org/wiki/Exponential_growth
Plenty of less-intelligent animals have been around since long before humans, and they will probably be around long after humans.
Ultimately all less intelligent animals on this planet will perish due to heat death of the sun unless we bring them with us to other planets.
Ultimately all life will disappear due to the heat death of the universe so why bother.
Humanity is fairly new, I doubt we'll make it to the heat death of the sun. Modern humans are 300 000 years old (anatomically, 50 000 behaviourally), the sun will run for another 5 000 000 000. We're running out of easy to use resources after not even 150 years of industrial progress, people are getting less and less healthy, fertility is going down thanks to pollution, many eco systems are on the verge of collapse with unpredictable consequences for us, &c.
I think we have many things to focus on before saving animals from the heat death of the sun
Humanity is fairly new, I doubt we'll make it to the heat death of the sun. Modern humans are 300 000 years old (anatomically, 50 000 behaviourally), the sun will run for another 5 000 000 000. We're running out of easy to use resources after not even 150 years of industrial progress, people are getting less and less healthy, fertility is going down thanks to pollution, many eco systems are on the verge of collapse with unpredictable consequences for us, &c.
I think we have many things to focus on before saving animals from the heat death of the sun
> We're running out of easy to use resources after not even 150 years of industrial progress,
All of human civilization (and some pre-civilization time) has been industrial progress, and even if you are counting from the beginning of the popularly-named Industrial Revolution, that's fairly arbitrary but also 260+ years, not 150.
All of human civilization (and some pre-civilization time) has been industrial progress, and even if you are counting from the beginning of the popularly-named Industrial Revolution, that's fairly arbitrary but also 260+ years, not 150.
The OP seemed to be saying that less intelligent animals have it made. It’s just us intelligent yet foolish humans who mess everything up.
My point was that ultimately, only intelligence will save us all. The dinosaurs tried the ignorance is bliss strategy.
My point was that ultimately, only intelligence will save us all. The dinosaurs tried the ignorance is bliss strategy.
You are assuming it is actually possible for human life to move to other solar systems.
It's much more likely that we could send bacteria or extremophiles to another planet and have them become self sustaining there than it is for a colony of humans, given everything we know today about the limits of space travel (time scale VS resource requirements).
It's much more likely that we could send bacteria or extremophiles to another planet and have them become self sustaining there than it is for a colony of humans, given everything we know today about the limits of space travel (time scale VS resource requirements).
my uneducated take is maybe other civilizations existed on earth or other planets but then self-destructed or got destroyed by a asteroid just like the dinos.
if human life on earth is a nano second in a day of the planet's life.
surely these things can come and go without leaving any traces. poof just varnish into thin air.
The flaw in our approach to the Fermi paradox is that we are looking for intelligent life which resembles us as we are now. Big, corporal bodies made of proteins communicating with big, inefficient, slow frequency vibrations. But this is just a transitory phase in our evolution which will pass in the astronomical blink of an eye.
Consider if you agree with these propositions:
- Consciousness is an emergent property of computation
- Computation is possible in any media
- Computation is more efficient in smaller, less massy media
- We are already beginning to fiddle with our own brains and this will accelerate
- Our bodies in general have huge room for optimization and eventually will be completely unrecognizable or even unnecessary as we currently imagine them
- Progress is exponential as our population grows in education, size and free time
If these are true, what does that mean for our destiny as a species in 100k years? 1M years?
I think we can all agree we will become cyborgs, but I think we still imagine our bodies having the same form factor. But that's the flawed assumption. Really we will shrink down. And what's the limit to how far down we shrink and how efficient and massless our bodies/brains get? How would we even be communicating in 1M years? Through entangled qubits? Vibrations in subspace? Who knows, but it's probably not something 21st century earth would even notice with a radio telescope.
So the answer to the Fermi paradox isn't that intelligent life snuffs itself out after a few million years. That's terribly unimaginative. The answer is that from our perspective intelligent civilizations disappear because they change themselves so radically that they transcend our concept of what to look for.
Consider if you agree with these propositions:
- Consciousness is an emergent property of computation
- Computation is possible in any media
- Computation is more efficient in smaller, less massy media
- We are already beginning to fiddle with our own brains and this will accelerate
- Our bodies in general have huge room for optimization and eventually will be completely unrecognizable or even unnecessary as we currently imagine them
- Progress is exponential as our population grows in education, size and free time
If these are true, what does that mean for our destiny as a species in 100k years? 1M years?
I think we can all agree we will become cyborgs, but I think we still imagine our bodies having the same form factor. But that's the flawed assumption. Really we will shrink down. And what's the limit to how far down we shrink and how efficient and massless our bodies/brains get? How would we even be communicating in 1M years? Through entangled qubits? Vibrations in subspace? Who knows, but it's probably not something 21st century earth would even notice with a radio telescope.
So the answer to the Fermi paradox isn't that intelligent life snuffs itself out after a few million years. That's terribly unimaginative. The answer is that from our perspective intelligent civilizations disappear because they change themselves so radically that they transcend our concept of what to look for.
> I think we can all agree we will become cyborgs,
Well, obviously! Who could imagine any other scenarios?! My mom just called me asking if i could replace her right foot with a hoverboard. I cant wait until I can no longer feel sunshine or grass. Living forever as a process in a virtual machine... my ancestors could have never dreamt of having such fulfillment.
Well, obviously! Who could imagine any other scenarios?! My mom just called me asking if i could replace her right foot with a hoverboard. I cant wait until I can no longer feel sunshine or grass. Living forever as a process in a virtual machine... my ancestors could have never dreamt of having such fulfillment.
You can only feel sunshine and grass because your brain interprets sensory signals from your body. It’s easy to imagine a world where your cyborg body can deliver those same signals. If the sensation is the same, why would you _not_ exhchange your fragile meat sack of a body with a far more versatile mechanical one?
Mechanical devices don't repair themselves. Living bodies do. I think you underestimate the highly optimized and resilient nature of a meat-sack body.
Mechanical devices don't repair themselves.
Only because we haven't bothered building any that do. A cynical take would be that it would be bad for the economy.
Only because we haven't bothered building any that do. A cynical take would be that it would be bad for the economy.
We don’t yet know how to build self-repairing machines. That’s basically the same as creating new life forms.
Well, creating life forms would require us to create self-reproducing machines, which doesn't seem like the same thing.
This will end up in a goalpost-shifting debate where the extent of self-repair capabilities necessary to qualify as "self-repairing" is argued. I'd say that a fault-tolerant system is at least 50% of the way there.
This will end up in a goalpost-shifting debate where the extent of self-repair capabilities necessary to qualify as "self-repairing" is argued. I'd say that a fault-tolerant system is at least 50% of the way there.
Perhaps, but imagine no need for surgery, no need for anesthesia, all wounds, illnesses and ailments fixed simply by switching the damaged part, or switching bodies entirely.
I think the fact that we will start to augment our bodies is a safe assumption. It's just too useful, and you will need to do it to compete. How will one get by without their AR retinal implants, brain chip and exoskeleton? Sure, it's dehumanizing but do you really think you will reject it? You are talking to me on a computer already... it won't always be external. When you age, you won't feel so sentimental about your teeth and spine anymore...
Now, if we let it rob us of sensations is another matter, and I think assuming that it will is the bigger leap. I imagine that in 10k years we will be able to integrate new parts with our nervous system. Think augmentation, not replacement, until the whole of the human body is replaced in form, but not necessarily function, like Theseus' ship, but without changing our experience too much.
Now, if we let it rob us of sensations is another matter, and I think assuming that it will is the bigger leap. I imagine that in 10k years we will be able to integrate new parts with our nervous system. Think augmentation, not replacement, until the whole of the human body is replaced in form, but not necessarily function, like Theseus' ship, but without changing our experience too much.
Your fundamental experiences as a human are already augmented by technologies so deeply integrated that our brains have changed to accommodate for them. For example: writing and speech.
What makes you think that "cyborg" means "foot replaced with hoverboard" and not things like "memory augmented with curated database" or "though process augmented with numeric-error-free calculation"?
What makes you think that "cyborg" means "foot replaced with hoverboard" and not things like "memory augmented with curated database" or "though process augmented with numeric-error-free calculation"?
Speech is not "a technology", it is a natural human ability. Our ability to form thoughts in the form of language and then communicate them (through speech or other ways, such as sign languages) is very likely of the same nature as our ability to see and interpret the world as objects.
Note that children do need interaction to learn to speak, but it is not taught to them in the sense that writing is, it is a natural instinct that they need social interaction to exercise (and they of course need to learn a particular firm of speech, i.e. one or more spoken or signed languages).
Though such experiments can't be carried out because they would risk being monstrous, it's quite possible that a group of babies growing up together with no spoken or signed interactions from their parents would still create a language of their own.
Note that children do need interaction to learn to speak, but it is not taught to them in the sense that writing is, it is a natural instinct that they need social interaction to exercise (and they of course need to learn a particular firm of speech, i.e. one or more spoken or signed languages).
Though such experiments can't be carried out because they would risk being monstrous, it's quite possible that a group of babies growing up together with no spoken or signed interactions from their parents would still create a language of their own.
>> technologies so deeply integrated that our brains have changed to accommodate for them. For example: writing and speech.
> Speech is not "a technology", it is a natural human ability ... of course need to learn a particular firm of speech, i.e. one or more spoken or signed languages).
So change that to "... 'technologies' so deeply integrated that our brains have changed to accommodate for them. For example: writing and language". AIUI, research suggests language has warped our brains.
> Speech is not "a technology", it is a natural human ability ... of course need to learn a particular firm of speech, i.e. one or more spoken or signed languages).
So change that to "... 'technologies' so deeply integrated that our brains have changed to accommodate for them. For example: writing and language". AIUI, research suggests language has warped our brains.
I fully agree with writing, but again, language itself is what I was talking about - it's a natural ability, not a technology we developed.
Adding to my previous examples, we also know that children can only natively learn particular structures of language, both in terms of grammar and phonology. You couldn't create a completely artificial lagauge and teach it natively to a child, they will be unable to learn the grammar and words, and they will sort of snap it back to a natural grammar and phonology.
Another good piece of proof is that you can't teach an animal language, even those that can be taught to use certain tools, or even to create tools of their own. You could probably create a group of chimpanzees that can use bows and arrows, and can share that knowledge from one generation to the next. But you can't teach even a single chimpanzee to use language in the sense that we do, even though every (healthy) human child learns it on their own within the first few years of life.
Adding to my previous examples, we also know that children can only natively learn particular structures of language, both in terms of grammar and phonology. You couldn't create a completely artificial lagauge and teach it natively to a child, they will be unable to learn the grammar and words, and they will sort of snap it back to a natural grammar and phonology.
Another good piece of proof is that you can't teach an animal language, even those that can be taught to use certain tools, or even to create tools of their own. You could probably create a group of chimpanzees that can use bows and arrows, and can share that knowledge from one generation to the next. But you can't teach even a single chimpanzee to use language in the sense that we do, even though every (healthy) human child learns it on their own within the first few years of life.
> - Consciousness is an emergent property of computation
That is quite a leap. I hope it is true but you never know what kind of quantum/other shenanigans sneaky evolution has latched on to to end up with the brains of today.
That is quite a leap. I hope it is true but you never know what kind of quantum/other shenanigans sneaky evolution has latched on to to end up with the brains of today.
FWIW I do think that if at all there is a quantum mechanism available and it has even a tiny evolutionary advantage it would end up being a significant part of rise of consciousness. from looking at things like photosynthesis its not too far fetched imo.
Yeah, we don't know the first thing about consciousness really. But I imagine with enough time we will be able to build an artificial neuron that's smaller. And induct from there.
We know one very important thing: consciousness is not a binary state. We have learned that different animals experience sensations, emotions at varying degrees. That different animals can solve problems of varying difficulty. And more advanced animals can communicate at varying levels of richness. When you stop thinking of consciousness, intellect and awareness as binary states but gradients (perhaps multidimensional), then you can more easily accept the premise that consciousness is an emergent property of the complex biological systems.
I imagine civilization will just be a solar powered server box floating through space running unreal engine 6.0x10^27
inshallah
> Consciousness is an emergent property of computation
It's interesting to see the negative comments about this here because I agree with you. "Consciousness" or even "sentience" is notoriously difficult to define. Even defining what an organism is isn't entirely obvious (eg some might consider a colony of ants or bees as being organism-like). Our views tend to be extremely human-centric because we can relate. I imagine once we actually invent an AGI many will debate if it's truly sentient or conscious for a long, long time afterwards.
> Computation is more efficient in smaller, less massy media
There are physical limits on computation. A smaller package ultimately has a lower limit. That alone will (IMHO) keep a space for very large computational units. At the top end of this is Matrioshka Brains [1].
A digital existence looks highly likely in the black hole era of the universe [2]. This is the era after all the stars have faded out and will be much longer (based on current understanding) than the stellar era, so much so that the 13-14B year lifetime of the universe thus far will be like the blink of an eye.
As for detecting communication, that's too narrow a focus. Whether we're miniscule cyborgs that communicate with qubits or living as virtual beings in a world-sized computer, the ultimate limits of what any such civilization can do is is the amount of energy they can consume. More energy means more is possible.
So even if we end up living as a K2 civilization in a billion orbitals around our Sun or one of the alternatives or build a Matrioshka Brain or simply collect all the power with satellites, all of these will have a similar IR signature that will be extremely detectable.
[1]: https://www.youtube.com/watch?v=Ef-mxjYkllw
[2]: https://www.youtube.com/watch?v=Qam5BkXIEhQ
It's interesting to see the negative comments about this here because I agree with you. "Consciousness" or even "sentience" is notoriously difficult to define. Even defining what an organism is isn't entirely obvious (eg some might consider a colony of ants or bees as being organism-like). Our views tend to be extremely human-centric because we can relate. I imagine once we actually invent an AGI many will debate if it's truly sentient or conscious for a long, long time afterwards.
> Computation is more efficient in smaller, less massy media
There are physical limits on computation. A smaller package ultimately has a lower limit. That alone will (IMHO) keep a space for very large computational units. At the top end of this is Matrioshka Brains [1].
A digital existence looks highly likely in the black hole era of the universe [2]. This is the era after all the stars have faded out and will be much longer (based on current understanding) than the stellar era, so much so that the 13-14B year lifetime of the universe thus far will be like the blink of an eye.
As for detecting communication, that's too narrow a focus. Whether we're miniscule cyborgs that communicate with qubits or living as virtual beings in a world-sized computer, the ultimate limits of what any such civilization can do is is the amount of energy they can consume. More energy means more is possible.
So even if we end up living as a K2 civilization in a billion orbitals around our Sun or one of the alternatives or build a Matrioshka Brain or simply collect all the power with satellites, all of these will have a similar IR signature that will be extremely detectable.
[1]: https://www.youtube.com/watch?v=Ef-mxjYkllw
[2]: https://www.youtube.com/watch?v=Qam5BkXIEhQ
> I think we can all agree we will become cyborgs
That was a leap.
I think we will become more like mycelium, or a root system connected in the ground. Still limiting us to terrestrial communication on the planet the network is placed on, but an optional ability to blast messages out if necessary.
That was a leap.
I think we will become more like mycelium, or a root system connected in the ground. Still limiting us to terrestrial communication on the planet the network is placed on, but an optional ability to blast messages out if necessary.
You don't think we're gonna want to move around?
We have need for stimuli not a need for movement. The movement being a surrogate for the need for stimuli or accessing where the stimuli is. We can reduce it directly to stimuli if that remains a need.
I think we're gonna want to explore the cosmos though. I could imagine doing that via sensors that travel while we sit here, but you could just say that's an extension of our artificial body.
Have you seen the backlash to people being recalled to the office? Doesn't seem so far fetched to me...
The matrix. You’re describing the matrix.
The closest pop culture reference I've seen was depicted in Avatar, where the planet wide root system could be used for consciousness transfer.
I'm describing that as there are various large networks on our planet already, whether fungi or plants, with some insect colonies acting similarly as a large single organism network.
The matrix didn't have communication between the organic nodes in the world they physically existed on, and is primarily focused on a simulated world. I'm not describing that at all, but I can see how its the nearest skeumorph barring any other examples.
I'm describing that as there are various large networks on our planet already, whether fungi or plants, with some insect colonies acting similarly as a large single organism network.
The matrix didn't have communication between the organic nodes in the world they physically existed on, and is primarily focused on a simulated world. I'm not describing that at all, but I can see how its the nearest skeumorph barring any other examples.
> Our bodies in general have huge room for optimization and eventually will be completely unrecognizable or even unnecessary as we currently imagine them
I think this is a huge leap, especially when it comes to computation. As far we can tell, the brain is amazingly energy efficient compared to to any electronic chip. It's hard to estimate exactly what kinds of computation our brains are doing so that we could compare in terms of teraflops, but the energy consumption is many times better than any processor that could come close in any reasonable estimation.
I think this is a huge leap, especially when it comes to computation. As far we can tell, the brain is amazingly energy efficient compared to to any electronic chip. It's hard to estimate exactly what kinds of computation our brains are doing so that we could compare in terms of teraflops, but the energy consumption is many times better than any processor that could come close in any reasonable estimation.
> I think we can all agree we will become cyborgs
Sent from my iPhone
Sent from my iPhone
Robin Hanson, who coined the term "Great Filter", presented a theory in 2021 to explain the Fermi Paradox. It's known as the "Grabby Aliens Theory".
This 12 minute video does a good job of explaining the fairly non intuitive reasoning: https://www.youtube.com/watch?v=l3whaviTqqg
As I understand it (it's not an easy theory to wrap your - or at least my - mind around), the reason we don't see any other civilizations is that we're among the first ones.
This seems very unlikely, but is actually not. Because a successful hi tech civilization would likely be inclined to expand ("be grabby") and fill up the galaxy in ~100 million years, as Fermi pointed out. That would mean all habitable planets would then be taken, and no more civilizations would rise up from primordial goo like ours.
That means - and it's a weird mental leap, but I think it's correct - that almost all civilizations arising "naturally" would have the same experience we have: The universe seems weirdly empty.
I guess it also means that the galaxy is ours for the taking!
This 12 minute video does a good job of explaining the fairly non intuitive reasoning: https://www.youtube.com/watch?v=l3whaviTqqg
As I understand it (it's not an easy theory to wrap your - or at least my - mind around), the reason we don't see any other civilizations is that we're among the first ones.
This seems very unlikely, but is actually not. Because a successful hi tech civilization would likely be inclined to expand ("be grabby") and fill up the galaxy in ~100 million years, as Fermi pointed out. That would mean all habitable planets would then be taken, and no more civilizations would rise up from primordial goo like ours.
That means - and it's a weird mental leap, but I think it's correct - that almost all civilizations arising "naturally" would have the same experience we have: The universe seems weirdly empty.
I guess it also means that the galaxy is ours for the taking!
If we're the forerunners, it's our responsibility to leave behind huge and mysterious artifacts containing the secrets of the universe, filled with traps for the unwary.
"Figby, get those doom-chompers synchronized with the shooting flames!"
"Yes sir!"
"And think of something more profound than 'Be nice to other beings and remember to call your mother(s)' for that final secret. Maybe get someone in the art department to help out."
It's not easy being the Elder Race, but someone has to do it.
"Figby, get those doom-chompers synchronized with the shooting flames!"
"Yes sir!"
"And think of something more profound than 'Be nice to other beings and remember to call your mother(s)' for that final secret. Maybe get someone in the art department to help out."
It's not easy being the Elder Race, but someone has to do it.
I'm missing something in these videos. Is it that the perception we're early implies an implausible scenario because "grabby" (I would just call them expansionist) civilizations would also be cloaking their signals (he seems to gloss over this point)? I.e. "they're out there" we just can't see them, or is he saying that would be implausible because we should have been invaded by now by these expansionist empires, therefore since we haven't we are early?
You seem to be saying the theory implies we are early when in the first video I got the impression that is statistically implausible.
I guess my main confusion is, if they are grabby, why haven't we been grabbed?
edit: watched the second video further, I think I get it a little better now. We are generally early and/or somehow advanced aliens expand quickly, otherwise we'd see signals because the signals would propagate faster than their expansion, whereas if they expand quickly, they'll invade us before we see signals, and dominate a larger portion of visible universe.
You seem to be saying the theory implies we are early when in the first video I got the impression that is statistically implausible.
I guess my main confusion is, if they are grabby, why haven't we been grabbed?
edit: watched the second video further, I think I get it a little better now. We are generally early and/or somehow advanced aliens expand quickly, otherwise we'd see signals because the signals would propagate faster than their expansion, whereas if they expand quickly, they'll invade us before we see signals, and dominate a larger portion of visible universe.
My interpretation, which I'm only 90% sure of, is that if we weren't early we'd be dead, since an earlier civilization would have colonized Earth for their own purposes.
So seeing no one else out there is to be expected.
It's a bit like how it's NOT weird that we happened to evolve on a planet that is so extremely favorable to our form of life.
So seeing no one else out there is to be expected.
It's a bit like how it's NOT weird that we happened to evolve on a planet that is so extremely favorable to our form of life.
That's not that new an idea. Even at 1% of c we could fully colonize the Milky Way in 10 million years, which is a blink of an eye compared to the >4B years the EArth has been here.
The second issue is that planets don't really matter other than being essentially "mass repositories". They're a highly inefficient way of creating living area. I'm speaking of course of Dyson Swarms as a highly likely alternative. I saw "highly likely" because it requires no new physics, no new materials beyond what we already have, is orders of magnitude more efficient (in living space per unit mass terms) and is essentially just an engineering problem (obviously a big one).
If you accept that premise then it's even less likely there are other spacefaring civilizations within our light cone because they would stick out like a sore thumb. Certainly a whole galaxy of these would be detectable by us currently from millions of light years away.
The second issue is that planets don't really matter other than being essentially "mass repositories". They're a highly inefficient way of creating living area. I'm speaking of course of Dyson Swarms as a highly likely alternative. I saw "highly likely" because it requires no new physics, no new materials beyond what we already have, is orders of magnitude more efficient (in living space per unit mass terms) and is essentially just an engineering problem (obviously a big one).
If you accept that premise then it's even less likely there are other spacefaring civilizations within our light cone because they would stick out like a sore thumb. Certainly a whole galaxy of these would be detectable by us currently from millions of light years away.
> more species are likely getting filtered further down the chain
My personal hunch is the filter is around multicellular life. We'll find lots of planets with single-celled goop. Many fewer with animals.
The unions that created photosynthesis and mitochondria look to have happened only once (successfully) in Earth's history [1], and sound more like voodoo than science the more one thinks about it. (Cell ate another cell then changed its mind and adopted it for 1.45 billion years.)
[1] https://www.nature.com/scitable/topicpage/the-origin-of-mito...
My personal hunch is the filter is around multicellular life. We'll find lots of planets with single-celled goop. Many fewer with animals.
The unions that created photosynthesis and mitochondria look to have happened only once (successfully) in Earth's history [1], and sound more like voodoo than science the more one thinks about it. (Cell ate another cell then changed its mind and adopted it for 1.45 billion years.)
[1] https://www.nature.com/scitable/topicpage/the-origin-of-mito...
The earliest signs of life at >3.5B years old [1] while photosynthesis dates to ~3.4B years ago. That seems to be pretty quick (by some definition, ~100 million years with huge error bars is "quick").
If photosynthesis only evolved once, another explanation is that it only needed to once because it was so wildly successful.
Multicellular is interesting. That obviously took much longer but once it did? Holy crap did things take off. I kinda wish I could have a time machine just to visit the Cambrian Explosion era.
[1]: https://en.wikipedia.org/wiki/Evolution_of_photosynthesis
If photosynthesis only evolved once, another explanation is that it only needed to once because it was so wildly successful.
Multicellular is interesting. That obviously took much longer but once it did? Holy crap did things take off. I kinda wish I could have a time machine just to visit the Cambrian Explosion era.
[1]: https://en.wikipedia.org/wiki/Evolution_of_photosynthesis
> A core idea of this is that there are various filters that separate a new planet from one hosting spacefaring life.
The most obvious, but least talked about filter is time.
Let’s assume there is a civilization just like us on the other end of the Milky Way galaxy, it’s not like we can just “look out” and observe them. Assuming they blasted out radio signals, those radio signals would have to have been sent 100,000 years ago for us to detect them today. Alternatively for that same civilization to detect our earliest radio signals it take another 999,900 years.
If this technologically advanced civilization was in the closest galaxy instead of the opposite end of the Milky Way, then our ability to detect one another’s signals traveling at the speed of light would be separated by over 2.5M years.
The most obvious, but least talked about filter is time.
Let’s assume there is a civilization just like us on the other end of the Milky Way galaxy, it’s not like we can just “look out” and observe them. Assuming they blasted out radio signals, those radio signals would have to have been sent 100,000 years ago for us to detect them today. Alternatively for that same civilization to detect our earliest radio signals it take another 999,900 years.
If this technologically advanced civilization was in the closest galaxy instead of the opposite end of the Milky Way, then our ability to detect one another’s signals traveling at the speed of light would be separated by over 2.5M years.
> The most obvious, but least talked about filter is time.
For good reason: there's been a lot of it so far. Even at slower than light speeds, it would be possible for a sufficiently advanced civilization to send probes to ever star in the galaxy (or even colonize it) in just a few million years. So why don't we see any evidence of any prior civilization having done that? It would only take one.
For good reason: there's been a lot of it so far. Even at slower than light speeds, it would be possible for a sufficiently advanced civilization to send probes to ever star in the galaxy (or even colonize it) in just a few million years. So why don't we see any evidence of any prior civilization having done that? It would only take one.
How long would they have to last though? We don't just have to both be advanced but also overlap in time. When you consider there are hundred million+ years between advanced life forms and intelligent life, and even millions of years between humans and intelligent humans, any signals of any kind may have to last for millions of years or more to be detected.
Then there's so much space, so it probably takes more than one. Perhaps a million+ more than one.
Then the final but to me most important thing, is we often assume advanced life looks like us. I personally believe it generally does -- for a bit. But if we're just a stepping stone to AI and then (perhaps) we disappear, advanced life forms like us only exist for a blip anyways. We probably don't even know what to look for. The possibilities are fascinating and humbling.
Then there's so much space, so it probably takes more than one. Perhaps a million+ more than one.
Then the final but to me most important thing, is we often assume advanced life looks like us. I personally believe it generally does -- for a bit. But if we're just a stepping stone to AI and then (perhaps) we disappear, advanced life forms like us only exist for a blip anyways. We probably don't even know what to look for. The possibilities are fascinating and humbling.
I suspect that could be part of it, that we're the biological bootloader for AI and we last just a blink in that stage on the time scale of the universe.
But then what does that AI do afterwards and why don't we see them. That doesn't really solve the dilemma.
But then what does that AI do afterwards and why don't we see them. That doesn't really solve the dilemma.
That is true although I suspect it might be like an ant and us -- the ant certainly interacts with us but does it, can it, know anything about us? Maybe the output of AI is all around us and we are simply (now and forever) incapable of "seeing" it. My other hunch is that communication at that level isn't actually required in the traditional sense, and anything that would need to be communicable is done so via truth seeking.
It wouldn't have to be a signal, it could be physical artifacts.
> …it would be possible for a sufficiently advanced civilization to send probes to ever star in the galaxy (or even colonize it) in just a few million years.
It’s “possible”, highlighted by the fact that we haven’t sent a single probe to another star system. We have a grand total of 2 probes that have made it outside our solar system, and only 3 more on the way.
There are an estimated hundred thousand million stars in the Milky Way. At a rounded cost of $1B for the Voyager missions, “possible” starts to meet reality.
There are far to many assumptions. Not only does a technological civilization exist, but it had a few million years head start on us and used their time/technology to colonize every star system in the galaxy with physical probes, when so long as we are making assumptions and can assume they have/had the ability to collect all the same data/information locally at the speed of light.
It’s “possible”, highlighted by the fact that we haven’t sent a single probe to another star system. We have a grand total of 2 probes that have made it outside our solar system, and only 3 more on the way.
There are an estimated hundred thousand million stars in the Milky Way. At a rounded cost of $1B for the Voyager missions, “possible” starts to meet reality.
There are far to many assumptions. Not only does a technological civilization exist, but it had a few million years head start on us and used their time/technology to colonize every star system in the galaxy with physical probes, when so long as we are making assumptions and can assume they have/had the ability to collect all the same data/information locally at the speed of light.
Cough, Egyptian pyramids, jump doors with runes,... :)
Now seriously, maybe we have and they just weren't interested.
Now seriously, maybe we have and they just weren't interested.
I'm pulling information from an introductory astronomy class, but isn't the definition of what lot of time passing is, not agreed upon?
/The Five Ages of the Universe/ by Adams and Laughlin theorize that new stars won't stop forming until trillions (possibly hundreds of trillions) of years after the universe's inception. We're currently on years 14-15 billion. If their theories are true we'd be, arguably, one of the first instances of intelligent life in the universe.
Now, some astronomers theorize that the universe will end in 5 - 15 billion years, so that would change the timeline substantially.
/The Five Ages of the Universe/ by Adams and Laughlin theorize that new stars won't stop forming until trillions (possibly hundreds of trillions) of years after the universe's inception. We're currently on years 14-15 billion. If their theories are true we'd be, arguably, one of the first instances of intelligent life in the universe.
Now, some astronomers theorize that the universe will end in 5 - 15 billion years, so that would change the timeline substantially.
The oldest stars in our galaxy are >12 billion years old. Ours is 4.5 billion years old. We obviously don't have a lot (meaning more than 1) of data points here but that one data point is that life can evolve in 4 billion years.
Whatever the variance is we've had ~3x that for other civilizations to arise in our galaxy alone.
Yes we could be "first" (within our cone of spacetime). First of 3? That's possible. First of 1000? Way less likely. There's some BAyesian reasoning about probability spaces you can do here. The very fact that we can't seem to detect anyone else in our galaxy changes the probabilities making it much more likely (but not impossible of course) that we're effectively alone.
Also the odds that another civilization evolves over 4B years and reaches spacefaring technology within 100,000 years of us is, statistically speaking, incredibly unlikely. It's way more likely they'll be way ahead of us or way behind us.
Whatever the variance is we've had ~3x that for other civilizations to arise in our galaxy alone.
Yes we could be "first" (within our cone of spacetime). First of 3? That's possible. First of 1000? Way less likely. There's some BAyesian reasoning about probability spaces you can do here. The very fact that we can't seem to detect anyone else in our galaxy changes the probabilities making it much more likely (but not impossible of course) that we're effectively alone.
Also the odds that another civilization evolves over 4B years and reaches spacefaring technology within 100,000 years of us is, statistically speaking, incredibly unlikely. It's way more likely they'll be way ahead of us or way behind us.
Also, who knows how long the window would last where a civilization uses electromagnetic waves to communicate, in the ways we would look for them? We've only used them for a hundred-plus years or so, maybe in another hundred we will be using something else. That would mean there is only a 200-year period where we emitted detectible radiation, which is only detectible within a certain radius, and the detector would have to be within that radius and listening during that 200-year window at exactly the right distance and time to catch it.
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> we've had billions of years. Why aren't ther emore signs of technological life?
I think the "billions of years" part is key.
Humanity might die in the next centuries, or at least stop progressing technologically due to our lack of sustainable planning. If a human like life existed 100m years ago in a nearby planet we wouldn't now even if we sent basic probes, you'd need to dig just like we need to dig to find dino bones.
Modern civilisation are maybe 5000-7000 years old, that's not even a blip in the universe history. The universe could develop millions of technologically advanced civilisations on different planets with no time overlap
I also feel like lots of people are too much into sci fi, nothing guarantees technological progress can go much further than what we have and allow for large scale space exploration. We might not see signs of technological life because the most advanced thing they came up with are a few probes and some radio signals sent from so far away that you statistically will not find even if you look for them.
The universe physical and time scale raise the fermi paradox, but the same physical and time scale give you an answer as to why we might not be able detect life
I think the "billions of years" part is key.
Humanity might die in the next centuries, or at least stop progressing technologically due to our lack of sustainable planning. If a human like life existed 100m years ago in a nearby planet we wouldn't now even if we sent basic probes, you'd need to dig just like we need to dig to find dino bones.
Modern civilisation are maybe 5000-7000 years old, that's not even a blip in the universe history. The universe could develop millions of technologically advanced civilisations on different planets with no time overlap
I also feel like lots of people are too much into sci fi, nothing guarantees technological progress can go much further than what we have and allow for large scale space exploration. We might not see signs of technological life because the most advanced thing they came up with are a few probes and some radio signals sent from so far away that you statistically will not find even if you look for them.
The universe physical and time scale raise the fermi paradox, but the same physical and time scale give you an answer as to why we might not be able detect life
Lately I've been thinking that perhaps our technological progress might be deterministically leading us to our own destruction (or a major and irrecoverable regression) through some kind of unavoidable dynamic evolving.
Like a combination of nuclear weapons, biotechnology or AI with a tragedy of the commons type situation derived from the same competitive social nature that is required for us (or any other society) to develop technologically.
Perhaps even the most basic property of life, the self-preserving tendency of a self-preserving structure once it randomly emerges, can lead with mathematical precision to its own destruction a few billion years later, regardless of the specifics and despite the profoundly complex mechanisms evolved in-between.
Perhaps long-lived advanced civilizations are not possible at all, and can be seen as a weird transient natural phenomenon; starting with hydrothermal vents and ending with billions of odd etched silicon fossils.
Perhaps even the most basic property of life, the self-preserving tendency of a self-preserving structure once it randomly emerges, can lead with mathematical precision to its own destruction a few billion years later, regardless of the specifics and despite the profoundly complex mechanisms evolved in-between.
Perhaps long-lived advanced civilizations are not possible at all, and can be seen as a weird transient natural phenomenon; starting with hydrothermal vents and ending with billions of odd etched silicon fossils.
The most likely reason is the one show in the simulation made in this paper, I recently posted here.
"Possible CETIs Within Our Galaxy and Communication Probability Among CETIs ": https://news.ycombinator.com/item?id=31449404"
"...human beings need to survive 50 (+250 -49) Myr to receive one signal from other CETIs. Our results may quantitatively explain why we have not detected any alien signals so far. The uncertainty of the results has been discussed in detail and would be alleviated with the further improvement of our astronomical observation ability in the future..."
The universe is a big, big place and civilizations come and go. We would need to be around for 50 million years, to have a good chance to catch a window that would match another civilization. We are barely around as a species for 2 million years and civilization is maybe 10,000 years old...
"Possible CETIs Within Our Galaxy and Communication Probability Among CETIs ": https://news.ycombinator.com/item?id=31449404"
"...human beings need to survive 50 (+250 -49) Myr to receive one signal from other CETIs. Our results may quantitatively explain why we have not detected any alien signals so far. The uncertainty of the results has been discussed in detail and would be alleviated with the further improvement of our astronomical observation ability in the future..."
The universe is a big, big place and civilizations come and go. We would need to be around for 50 million years, to have a good chance to catch a window that would match another civilization. We are barely around as a species for 2 million years and civilization is maybe 10,000 years old...
I've always held the belief that given the vastness of space, and the age of time, it's not just a question of if other intelligent life can exist, but whether or not we we will be in the same place at the same time.
What if the probability of life forming on any given planet was so infinitesimally tiny that it happening on earth is already a fluke?
I would think that it's shortsighted. Just on Earth, we've been through several millions of years of various evolutions. We've had fauna, mega fauna, mega flora, dinosaurs, so many things have occurred over millions of years. It's hard to believe that none of this has possibly occurred elsewhere.
Edit: for clarity
Edit: for clarity
You're talking about evolution, I'm talking about life forming. More specifically, think about the likelihood of a cell forming from purely chemical reactions and kinetics.
While we're speculating, allow me to throw my 2 cents in.
The biochemistry of life is likely to be common, the conditions for complex or even intelligent tool using life are likely to be rare.
To have an earth, you need to have a moon comparable in mass to the planet to avoid atmospheric stripping. A temperature regime stable enough to support long term life development between 0 and 100 C. A star that doesn't blasttge planet in radiation every few thousand years. Along with a reasonable balance of materials, and a stellar neighborhood which wont swing the balance too badly every few million years.
Lastly, although untested, To have tool use, you likely need a planet with gravity thats strong enough for the atmosphere to be stable, but weak enough for organic molecules to hold together complex life and enable the construction of material objects. A super earth covered in algae is interesting, but may not be capable of traditional human intelligence.
The biochemistry of life is likely to be common, the conditions for complex or even intelligent tool using life are likely to be rare.
To have an earth, you need to have a moon comparable in mass to the planet to avoid atmospheric stripping. A temperature regime stable enough to support long term life development between 0 and 100 C. A star that doesn't blasttge planet in radiation every few thousand years. Along with a reasonable balance of materials, and a stellar neighborhood which wont swing the balance too badly every few million years.
Lastly, although untested, To have tool use, you likely need a planet with gravity thats strong enough for the atmosphere to be stable, but weak enough for organic molecules to hold together complex life and enable the construction of material objects. A super earth covered in algae is interesting, but may not be capable of traditional human intelligence.
My preferred speculation is simply that faster-than-light travel is impossible, so all the tool-using aliens out there are not visiting us because they can't, and we can't hear their signals because it gets lost against the background noise.
I mean, would we be able to detect our own civilization from a few lightyears out? Apparently, unless you're pointing a radio telescope right at something, you woudn't be able to pick up human civilization levels of radio from more than a lightyear out. Say there's one smart tool-using civilization per 5000 lightyear volume, then they're unlikely to meet.
I mean, would we be able to detect our own civilization from a few lightyears out? Apparently, unless you're pointing a radio telescope right at something, you woudn't be able to pick up human civilization levels of radio from more than a lightyear out. Say there's one smart tool-using civilization per 5000 lightyear volume, then they're unlikely to meet.
Even if a civilization out there had faster-than-light travel, they would most likely not know we were here. They would need to decide to come explore near us, probably need to expensively slow down to sub-light speeds to look for signs of life near here and pick up our emissions on some old archaic piece of equipment they happened to bring along.
Would a much more advanced civilization spend their exploration budget to look over uninteresting primitives like us, or would they go off in search of other more advanced civilizations like their own?
Would a much more advanced civilization spend their exploration budget to look over uninteresting primitives like us, or would they go off in search of other more advanced civilizations like their own?
> To have an earth, you need to have a moon comparable in mass to the planet to avoid atmospheric stripping.
Could you elaborate on this? I'm aware that magnetospheres protect atmospheres from solar wind stripping (e.g., https://science.nasa.gov/science-news/news-articles/earths-m...), but have never heard of the role of moons, and can't find anything via Google right now.
Could you elaborate on this? I'm aware that magnetospheres protect atmospheres from solar wind stripping (e.g., https://science.nasa.gov/science-news/news-articles/earths-m...), but have never heard of the role of moons, and can't find anything via Google right now.
You also need plate tectonics. And exactly the right level of stellar radiation for the carbonate-silicate cycle to work, if you want photosynthesis, and without that you likely won't have anywhere near enough energy available for complex life.
Get any of it wrong and life either won't develop, or will wreck its own biosphere in an unrecoverable way very early on and get wiped out (if there was ever life on Mars, that's my bet for why traces of it are elusive—it wasn't around very long, wasn't very complex, and it was a very long time ago).
Get any of it wrong and life either won't develop, or will wreck its own biosphere in an unrecoverable way very early on and get wiped out (if there was ever life on Mars, that's my bet for why traces of it are elusive—it wasn't around very long, wasn't very complex, and it was a very long time ago).
Can you elaborate? What's the reason it wouldn't work if all the plates were frozen?
Maybe not strictly necessary for any life, but the broad principal is that any process that recycles material is going to be really helpful to life, with big bonus points for it working in a dynamic fashion so it tends to self-stabilize—plate tectonics don't have that quality, but other processes do, like any chemical process where the concentration affects the rate at which the process occurs, or how our climate tends to find stable points rather than having runaway freezing or runaway heating.
In the Earth's case, vulcanism is critical to balancing atmospheric CO2 levels. Over time (not on human timescales) carbon tends to get trapped in ways that make it unavailable to life, so you need something to undo that, and that's a major mechanism for it.
Life may be (probably is) possible without some elements of what makes life work on Earth, but with the wrong environment may destroy itself relatively quickly (as life on Earth nearly did, during the oxygenation crisis) or fail to capture enough energy for the development of complex life (think: a planet where the only energy available to life comes from a few undersea vents, photosynthesis being impossible for any of several reasons).
For this reason, a planet being in the "Goldilocks zone" around its host star is just the bare minimum required for widespread, complex life. The planet itself must also be more-or-less the right size, and must have the right composition of surface and atmosphere and various processes occurring (geological and otherwise) to keep those in balance, and so on. It's possible there are certain very hardy chemistries possible for life that we simply don't see on Earth because they're easily outcompeted by what we've already got, but those pretty much by definition won't provide as much energy to the host body's biosphere, so complex life is less likely. It's also possible there are planets far more amenable to life than Earth (though perhaps wholly incompatible with Earth-like life), with unknown-to-us chemistries that are only viable in that kind of even-better environment.
In the Earth's case, vulcanism is critical to balancing atmospheric CO2 levels. Over time (not on human timescales) carbon tends to get trapped in ways that make it unavailable to life, so you need something to undo that, and that's a major mechanism for it.
Life may be (probably is) possible without some elements of what makes life work on Earth, but with the wrong environment may destroy itself relatively quickly (as life on Earth nearly did, during the oxygenation crisis) or fail to capture enough energy for the development of complex life (think: a planet where the only energy available to life comes from a few undersea vents, photosynthesis being impossible for any of several reasons).
For this reason, a planet being in the "Goldilocks zone" around its host star is just the bare minimum required for widespread, complex life. The planet itself must also be more-or-less the right size, and must have the right composition of surface and atmosphere and various processes occurring (geological and otherwise) to keep those in balance, and so on. It's possible there are certain very hardy chemistries possible for life that we simply don't see on Earth because they're easily outcompeted by what we've already got, but those pretty much by definition won't provide as much energy to the host body's biosphere, so complex life is less likely. It's also possible there are planets far more amenable to life than Earth (though perhaps wholly incompatible with Earth-like life), with unknown-to-us chemistries that are only viable in that kind of even-better environment.
The list of prerequisites is much longer. Right amount of radiation, rotating molten metallic core (that probably came from collision with another planet!), jupiter-like vacuum cleaner to not have massive asteroid impacts too often - but sometimes they may help, like for us. Stable, boring star.
The list is probably much longer, ie chemistry part mixed with geology, astronomy and other topics.
The list is probably much longer, ie chemistry part mixed with geology, astronomy and other topics.
A good way to understand this is through an ocean world thought experiment. If a hypothetical planet existed which was covered in a 100km deep ocean, all nutrients would steadily fall to the bottom of the ocean - where there would be minimal to no energy to make use of the nutrients. You'd eventually be left with a surface layer containing only the minimal amounts of nutrients which diffusion pulls back up to the surface.
In order for this hypothetical water world to host a thriving ecosystem, you would need a large moon or heavy vulcanism to ensure that the oceans remain mixed.
In order for this hypothetical water world to host a thriving ecosystem, you would need a large moon or heavy vulcanism to ensure that the oceans remain mixed.
Plate tectonics helps with carbon recycling and regulating the temperature of the planet.
Temperature drops, rainfall drops (less evaporation), rock weathering slows down (rock weathering normally removes CO2 from the atmosphere).
With plate tectonics, volcanism continues to spew CO2 in the atmosphere, temperature eventually rises. Negative feedback.
No plate tectonics, no volcanism, albedo increases, temperature drops further. Positive feedback.
Temperature drops, rainfall drops (less evaporation), rock weathering slows down (rock weathering normally removes CO2 from the atmosphere).
With plate tectonics, volcanism continues to spew CO2 in the atmosphere, temperature eventually rises. Negative feedback.
No plate tectonics, no volcanism, albedo increases, temperature drops further. Positive feedback.
But you're assuming that life must contain good quantities of water, and in all 3 phases on the planet.
Silicon life could definitely be a thing.. However silicon bonds are a lot lower energy than carbon bonds are, for most substances. (I would argue that oxygen would be toxic to silicon based beings, due to Si-O.). So, I'd theorize that silicon based living beings would have to be in an atmosphere of, say, methane. And the phasegraph of methane ( https://www.engineeringtoolbox.com/methane-d_1420.html ) would seem to show that -175c and around there would be ideal temps for silicon life.
However, if we're exclusively only looking for carbon/oxygen/water based lifeforms, then I think the 0-100c is a reasonable assumption.
Silicon life could definitely be a thing.. However silicon bonds are a lot lower energy than carbon bonds are, for most substances. (I would argue that oxygen would be toxic to silicon based beings, due to Si-O.). So, I'd theorize that silicon based living beings would have to be in an atmosphere of, say, methane. And the phasegraph of methane ( https://www.engineeringtoolbox.com/methane-d_1420.html ) would seem to show that -175c and around there would be ideal temps for silicon life.
However, if we're exclusively only looking for carbon/oxygen/water based lifeforms, then I think the 0-100c is a reasonable assumption.
Don't you need carbon because the C-C bonds won't be disrupted by O2? I read that somewhere iirc in Larry Gonick's cartoon about chemistry.
can't be disrupted by O2 if there's no O2 in your environment
The law of large numbers comes into play here.
There are at least 100B stars in our galaxy. Over the last 20+ years we've gained a lot data on exoplanets. Exoplanetary systems seem to be really common. So stability, the right elements, etc no doubt all play a role but we may be talking over WWhata trillion planetary bodies (including large moons).
What's more, our understanding of where live can evolve, survive and thrive has greatly expanded in recent decades and now includes volcanic vents on the ocean floor, for example.
So yes a lot of things have to go right but we're rolling an awful lot of dice.
There are at least 100B stars in our galaxy. Over the last 20+ years we've gained a lot data on exoplanets. Exoplanetary systems seem to be really common. So stability, the right elements, etc no doubt all play a role but we may be talking over WWhata trillion planetary bodies (including large moons).
What's more, our understanding of where live can evolve, survive and thrive has greatly expanded in recent decades and now includes volcanic vents on the ocean floor, for example.
So yes a lot of things have to go right but we're rolling an awful lot of dice.
Yes, but the fermi paradox focuses on intelligent life. Even if there are ~10 trillion of possible planets in the galaxy for intelligent life to evolve on, that is only 10^14th power. If each of the circumstances described above is a 1 in 100 event, then that leaves only 10^5 habitable planets for intelligent life to evolve across the entire galaxy. If you then consider that there is a 5 in 4.5 billion chance that such a planet currently has an intelligent life form on it, then it's quite possible that there are no other intelligent life forms in the galaxy. However there may be millions or billions of planets with evolved forms of algae.
Now, I do not believe that these are uncorrelated probabilities - and as such I'd place the odds quite a bit higher. But the more we learn about planetary physics, the more unique earth appears to be. Meanwhile, it appears that the biochemistry of life is incredibly common.
Now, I do not believe that these are uncorrelated probabilities - and as such I'd place the odds quite a bit higher. But the more we learn about planetary physics, the more unique earth appears to be. Meanwhile, it appears that the biochemistry of life is incredibly common.
"but we're rolling an awful lot of dice."
but are the odds better than 2^256 ? https://youtu.be/S9JGmA5_unY?t=38
but are the odds better than 2^256 ? https://youtu.be/S9JGmA5_unY?t=38
Lots of child comments have made statements about what life 'needs' and why that would make things difficult.
We don't know what conditions life 'needs' since we only have a sample size of 1. We can speculate, but nothing yet is a known fact.
We don't know what conditions life 'needs' since we only have a sample size of 1. We can speculate, but nothing yet is a known fact.
Right. It's not like we would theorize the existence of biological life on earth from first principles if we didn't know about it beforehand. It's such a magical, complex thing. We have no idea what other kinds of incomprehensibly complicated reactions might occur.
Anyone interested in this topic should check out Stephen Webb's book, "If the Universe Is Teeming with Aliens ... Where Is Everybody?".
It's not perfect, but it goes over a lot of possible explanations (75 different explanations!) for the Fermi Paradox. It covers pretty much every theory I've seen when people discuss the topic, aside from a government cover-up haha.
Simulations, aliens hiding on Earth, von Neumann probes, signals that we don't understand, distances being insurmountable, self-destructiveness, inescapable planets, singularities, it's got it all! A lot of the explanations ultimately can't get over the "OK, but surely there are at least a few exceptions" problem, but it's very fun to think about nonetheless. A really engrossing read if you like thinking about this stuff!
https://www.goodreads.com/en/book/show/180506.If_the_Univers...
It's not perfect, but it goes over a lot of possible explanations (75 different explanations!) for the Fermi Paradox. It covers pretty much every theory I've seen when people discuss the topic, aside from a government cover-up haha.
Simulations, aliens hiding on Earth, von Neumann probes, signals that we don't understand, distances being insurmountable, self-destructiveness, inescapable planets, singularities, it's got it all! A lot of the explanations ultimately can't get over the "OK, but surely there are at least a few exceptions" problem, but it's very fun to think about nonetheless. A really engrossing read if you like thinking about this stuff!
https://www.goodreads.com/en/book/show/180506.If_the_Univers...
Consider factors like the age of the universe, stars growing more metallic as they form starting with elements that can only be made by others going supernova, and chances of the planet not being hit by a supernova strong enough to sterilize the planet for billions of years. The great filter isn't necessarily still yet to come.
What observation methods would one use to detect life on Earth from even a moderate distance away? It is not known to me that we have the capability to even discover life on Earth if we were in another planet in another system.
As far as I understand, exoplanet discovery and study is still incredibly rudimentary.
As far as I understand, exoplanet discovery and study is still incredibly rudimentary.
SETI began by looking for radio signals that were highly unlikely to be "random" because that fit what we ourselves were using at the time. As we've since discovered, this sort of communication was shortlived lasting just decades.
So what could we observe instead? The answer is Dyson Swarms. These aren't rigid spheres as some seem to think (the original term was "Dyson Sphere" but is largely abandoned because of the confusion). It's merely a collection of orbitals to consume all the energy a star produces. Many (myself included) think this is the inevitable direction of our species.
The only way to get rid of heat in space is to radiate it away. The frequency of the light emitted depends entirely on the temperature of the radiating object. This means a full Dyson Swarm would have a huge infrared signature. That sort of thing we could detect from a very far distance. A whole galaxy of these would be detectable from millions of light years away.
So what could we observe instead? The answer is Dyson Swarms. These aren't rigid spheres as some seem to think (the original term was "Dyson Sphere" but is largely abandoned because of the confusion). It's merely a collection of orbitals to consume all the energy a star produces. Many (myself included) think this is the inevitable direction of our species.
The only way to get rid of heat in space is to radiate it away. The frequency of the light emitted depends entirely on the temperature of the radiating object. This means a full Dyson Swarm would have a huge infrared signature. That sort of thing we could detect from a very far distance. A whole galaxy of these would be detectable from millions of light years away.
I wasn't necessarily trying to address what we can look for. I was trying to ask, what are things we are even capable of looking for? I am aware of Dyson swarms, but is it not the case that the enumeration of objects that emit infrared large?
The Fermi paradox is not really a paradox of sorts, especially given when it was formulated. Because if we aren't even capable of detecting life, then how can we ask where is it?
The Fermi paradox is not really a paradox of sorts, especially given when it was formulated. Because if we aren't even capable of detecting life, then how can we ask where is it?
The Fermi Paradox isn't a paradox to many (including, I believe, Fermi). The answer many suspect (myself included) is that spacefaring life is incredibly rare so it's not really a "paradox" because there is nothing to detect.
As for amino acids, I would just work on the assumption that they, and nucleosides, sort of people out of space organic chemistry on a regular basis, in a way that has nothing to do with life, but just basic chemistry/physics.
The universe is infinite and continuously expanding. This cosmological scale, the monumental distance between celestial objects in deep space, would make it quite literally impossible for any extraterrestrial to feasibly be aware of or make contact with humans and vice versa. Even if we could travel beyond the speed of light, we'd still probably never make contact; there would be too many things that could go wrong. It's depressing to think about.
Space limits everything, and is the simplest solution to the Fermi paradox (following Occam's razor).
Source: I am a software engineer who works on cool space stuff
Space limits everything, and is the simplest solution to the Fermi paradox (following Occam's razor).
Source: I am a software engineer who works on cool space stuff
The Fermi paradox is a joke (literally.) It’s not meant to be taken seriously as science but as proof our understanding, specifically irt how we got complex life, is flawed. I really hate that there are entire media spheres dedicated to philosophizing about it.
It also does little but derail every conversation about life in the universe into speculative science fiction.
It also does little but derail every conversation about life in the universe into speculative science fiction.
My intuition is that life was formed using amino acids because they are common substances that occur naturally where liquid water is around.
Not because they have any unique lifeforming property.
Not because they have any unique lifeforming property.
It's this another point in favor of the panspermia hypothesis?
No, since this is not life or things definitely made by life. It's a point in favour of pseudo-panspermia (https://en.wikipedia.org/wiki/Pseudo-panspermia). Amino acids have been found in comets before, though it sounds like they found more here.
And what’s quite interesting about the pseudo-panspermia hypothesis…
https://en.wikipedia.org/wiki/Abiogenesis#Homochirality
…is the chirality of the molecules we’ve found on comets and meteorites. The amino acids and sugars out in space match what we find in Earth biology. That in way proves that some of the building blocks of life on Earth were generated in the Solar System, but at least it’s a plausible link.
https://en.wikipedia.org/wiki/Abiogenesis#Homochirality
…is the chirality of the molecules we’ve found on comets and meteorites. The amino acids and sugars out in space match what we find in Earth biology. That in way proves that some of the building blocks of life on Earth were generated in the Solar System, but at least it’s a plausible link.
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Can anyone point me in the right direction of a paper that talks more about this?
“Soluble Organic Compounds in Asteroid 162173 Ryugu”: https://www.hou.usra.edu/meetings/lpsc2022/pdf/1781.pdf
I'm not sure if you're asking specifically about this data or the General topic. If it's the general topic the Wikipedia article links to a few. https://en.m.wikipedia.org/wiki/Pseudo-panspermia
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So life beyond Mars confirmed then?
No, but some building blocks of life are found on an asteroid. So we know now that those molecules are present there. We have found amino acids in gas clouds in space before.
Wait what? How was that not bigger news?? How is not finding them on an asteroid not bigger news??? This brings up many more questions than answers, but how is it not possible at least to say that we're not the only place in the universe where life exists?
Because naturally-occurring amino acids are nothing new. You can make them yourself by sticking some chemicals together and applying energy to the mixture [0].
"Building blocks of life" is a phrase with no strong definition. Science journalists like to apply it to anything from water to DNA chains, though those are very different molecules in terms of complexity.
0: https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment
"Building blocks of life" is a phrase with no strong definition. Science journalists like to apply it to anything from water to DNA chains, though those are very different molecules in terms of complexity.
0: https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment
It's important to understand what amino acids are, if you want to know why this is more "interesting, but only somewhat so, science" than "groundbreaking news that changes our view of life in the universe": https://en.wikipedia.org/wiki/Amino_acid#General_structure
Those may seem complicated, but you have to also remember an "amino acid" is the entire family, and carbon tends towards "a bit complicated" naturally because it has so many bonds it needs to fill in. Fill an environment with carbon and the right other elements and it isn't "surprising" that amino acids form, it's inevitable. Like, literally unavoidable, you couldn't stop it if you tried. "The right environment for amino acids" would also be full of many other larger structures. It's a thing carbon does no matter where it is, not an exception. They would just be, if you'll pardon the convenient anthropomorphization, pointlessly larger structures, not doing anything in particular or having any particularly interesting properties beyond size. You get similarly large carbon structures in the soot of a fire, for instance.
Compare with hemoglobin, just to pick a popular protein of moderate size: https://en.wikipedia.org/wiki/Hemoglobin#Structure_of_heme This is a specific combination of 574 amino acids, in the correct chirality. Some deviations are possible that will retain functionality, it isn't that exact 574 amino acids, but there's limited variation possible. "Things useful for life" are much more than just bare amino acids.
This isn't something that should be downplayed; it is legitimately interesting, but at the same time, it doesn't materially move our probabilities on any particular theory of life because it was always predictable that amino acids would exist elsewhere in the universe. At a bare minimum for excitement would be demonstrating some sort of significant chirality preference. That would turn some heads.
Those may seem complicated, but you have to also remember an "amino acid" is the entire family, and carbon tends towards "a bit complicated" naturally because it has so many bonds it needs to fill in. Fill an environment with carbon and the right other elements and it isn't "surprising" that amino acids form, it's inevitable. Like, literally unavoidable, you couldn't stop it if you tried. "The right environment for amino acids" would also be full of many other larger structures. It's a thing carbon does no matter where it is, not an exception. They would just be, if you'll pardon the convenient anthropomorphization, pointlessly larger structures, not doing anything in particular or having any particularly interesting properties beyond size. You get similarly large carbon structures in the soot of a fire, for instance.
Compare with hemoglobin, just to pick a popular protein of moderate size: https://en.wikipedia.org/wiki/Hemoglobin#Structure_of_heme This is a specific combination of 574 amino acids, in the correct chirality. Some deviations are possible that will retain functionality, it isn't that exact 574 amino acids, but there's limited variation possible. "Things useful for life" are much more than just bare amino acids.
This isn't something that should be downplayed; it is legitimately interesting, but at the same time, it doesn't materially move our probabilities on any particular theory of life because it was always predictable that amino acids would exist elsewhere in the universe. At a bare minimum for excitement would be demonstrating some sort of significant chirality preference. That would turn some heads.
Especially when the life-relevant amino acids are mixed with all sorts of irrelevant amino acids, with the concentration of any particular species of molecule declining exponentially with the number of atoms it contains. This is supposed to be exciting?
It is uncertain where the amino acids on earth came from. A leading theory is that asteroids and comets seeded the early earth with a good mix of them.
So it is a data point supporting the idea that they could have been a source of these molecules. You may or may not find that exciting.
So it is a data point supporting the idea that they could have been a source of these molecules. You may or may not find that exciting.
I just find it an indication that formation of amino acids is not that important as a bottleneck for the origin of life. It's also not that surprising, as you'd expect life to use monomers that are fairly stable (and therefore could be formed by random processes, because of that stability.)
I think the conclusion is more amino acids form naturally without life rather than amino acid based life is widespread.
Indeed.
It would actually be more surprising if it turned out the molecules we are built from do not arise easily and naturally.
This doesn't mean that all life would be based off them though.
It would actually be more surprising if it turned out the molecules we are built from do not arise easily and naturally.
This doesn't mean that all life would be based off them though.
It's common knowledge among those who're interested, most people simply don't care.
>how is it not possible at least to say that we're not the only place in the universe where life exists?
Almost every expert believes that. In fact, it's entirely possible life didn't originate on earth in the first place. Not that it necessarily has an origin outside the solar system, but who knows.
>how is it not possible at least to say that we're not the only place in the universe where life exists?
Almost every expert believes that. In fact, it's entirely possible life didn't originate on earth in the first place. Not that it necessarily has an origin outside the solar system, but who knows.
Well, we know that we can produce some amino acids from the so-called "primordial soup" (which hit the news in the 50s). But there is still a wide gap between these simple chemicals and a simplest living organism.
It’s not possible because we’ve not yet observed it. It’s possible to say it’s very possible, but the strong assertion isn’t valid without proof.
Exactly that's why I was perplexed I got the first comment on this thread and that nobody seems to care.
Sorry, that was me.
Let's assume for a while that amino acids are everywhere in the solar system or galaxy (if not universe). Let's also assume that there are many earth-like planets.
If we found alien life on another earth-like planet, could it be possible that it too would have independently-evolved DNA? Not just DNA-like substances, but chemically identical DNA?
I guess I am wondering was DNA such an incredible fluke here on earth that we'll never see it again, or is it "the logical conclusion" for a bunch of similar amino acids in very similar environments? IIRC DNA is a chemically stable structure etc