Are we alone in the universe?

QuestorQuestor Shipmate
Since the time of Plato and Aristotle, our concept of the Universe has expanded from a few thousand stars to a multitude of galaxies and stars in their billions and thousands of billions.
Indeed with the Hubble telescope, stars and galaxies extend wherever we look going back billions of years.
Hubble is soon to be replaced by an even more powerful telescope the James Webb space telescope. Who knows what even greater splendours will be revelled?
I like to speculate that God has created other creatures with their own special relationship to Him
C S Lewis in his famous trilogy speculated this kind of event in our own solar system.

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Comments

  • Bishops FingerBishops Finger Shipmate
    edited May 13
    We Are Not Alone - Star Trek proves it...

    Seriously, though, we don't know, but it's entertaining to speculate.

    Alice Meynell's poem Christ in the Universe looks at it from a slightly different, but Christian, perspective:
    poetry-archive.com/m/christ_in_the_universe.html
  • Martin54Martin54 Shipmate
    edited May 13
    We do know. No sprculation is necessary. Only absolute certainty. By uniformitarianism we are average, normal, mediocre, insignificant. Like the universe itself, of infinite, from eternity. Which means Jesus is. He's unique for us. Just like He is for every other of infinite species with shared intentionality. From eternity. And demons-R-us. Of course scientifically we'll never prove it. So what?
  • Marvin the MartianMarvin the Martian Admin Emeritus
    I don’t think earth is the only place with life in the universe. Or even in our own solar system, for that matter. Every discovery made - exoplanets, organic chemistry on asteroids, etc - points further in the direction of life being quite common.

    In fact, I’m reasonably confident that we’ll find evidence of life somewhere else within my lifetime. Europa, maybe.

    Whether we ever find evidence of intelligent life somewhere out in space* is a lot more unlikely. The sheer size and age of the universe as well as the time needed for intelligent life to evolve makes it vastly improbable that two such civilisations would exist at the same time in close enough proximity to each other to be able to detect each other.

    .

    *= ...because there’s bugger all down here on earth. [/python]
  • Europa? But we've left the Europan Union...

    I'll get me Invisibility Cloak...
  • Martin54Martin54 Shipmate
    edited May 13
    I don’t think earth is the only place with life in the universe. Or even in our own solar system, for that matter. Every discovery made - exoplanets, organic chemistry on asteroids, etc - points further in the direction of life being quite common.

    In fact, I’m reasonably confident that we’ll find evidence of life somewhere else within my lifetime. Europa, maybe.

    Whether we ever find evidence of intelligent life somewhere out in space* is a lot more unlikely. The sheer size and age of the universe as well as the time needed for intelligent life to evolve makes it vastly improbable that two such civilisations would exist at the same time in close enough proximity to each other to be able to detect each other.

    .

    *= ...because there’s bugger all down here on earth. [/python]

    Interstellar communication is utter bollocks. One way, let alone two. Like economic nuclear fusion, AI, cures for dementia, arthritis, bipolarity, you name it, but bigger. Bollocks.
  • Hmm. Detection is one thing, communication quite another...I agree that both are rather unlikely, though.
  • Martin54Martin54 Shipmate
    Impossible. Utterly, eternally, economically, politically, technologically impossible. Detect how? What? With what?
  • communication:
    magic numbers, like the golden ratio, pi, Fibonacci numbers, atomic numbers
  • Mercy! Have mercy! I yield! I yield!
    :scream:
  • Martin54Martin54 Shipmate
    edited May 13
    communication:
    magic numbers, like the golden ratio, pi, Fibonacci numbers, atomic numbers

    Might you elaborate as to how they are communication? They are prevenient of God, so it's not Him. What do they communicate, prey? And how?
  • Martin54Martin54 Shipmate
    Mercy! Have mercy! I yield! I yield!
    :scream:

    Sorry, this is 15 rounds, on points. Put up your dukes.
  • mousethiefmousethief Shipmate
    I don’t think earth is the only place with life in the universe. Or even in our own solar system, for that matter. Every discovery made - exoplanets, organic chemistry on asteroids, etc - points further in the direction of life being quite common.

    Except for the fact of not actually discovering any.
  • Simon ToadSimon Toad Shipmate
    Well I don't know about other countries, but in Australia we have plenty of other species.
  • There are math numbers that are reflected in the structure of the physical world. Those would be likely communication introductions.
  • Martin54Martin54 Shipmate
    There are math numbers that are reflected in the structure of the physical world. Those would be likely communication introductions.

    Yeah, I've read A For Andromeda and Contact and everything in between. Both yearningly superb. Sagan's conceit with pi in the book is it's greatest flaw. The film is actually better for once.

    I know that's what you were inferring and implying.

    How would they be communicated, are they being communicated, apart from by nature?
  • Martin54Martin54 Shipmate
    I don’t think earth is the only place with life in the universe. Or even in our own solar system, for that matter. Every discovery made - exoplanets, organic chemistry on asteroids, etc - points further in the direction of life being quite common.

    In fact, I’m reasonably confident that we’ll find evidence of life somewhere else within my lifetime. Europa, maybe.

    Whether we ever find evidence of intelligent life somewhere out in space* is a lot more unlikely. The sheer size and age of the universe as well as the time needed for intelligent life to evolve makes it vastly improbable that two such civilisations would exist at the same time in close enough proximity to each other to be able to detect each other.

    .

    *= ...because there’s bugger all down here on earth. [/python]

    While we're dealing with the rational impossibility of detecting extrasolar civilization, which nobody has suggested any mechanism for yet:

    I've still got my hopes pinned on spectroscopy empirically proving the fact, the rational certainty of extrasolar life by detecting oxygen and water vapour. One rationally cannot say that one does not think earth is the only place with life in the universe. Unless 'think' is shorthand for rational P=1 certitude due to uniformitarianism, Kolmogorov complexity and common sense. Life is universal. Life sharing intentionality. Mere assertion of that is just fine. As is the extrapolation of Kolmogorov to infinite universes form eternity in physical cosmology. P=1. No 'debate' is rationally possible regardless of rationally impossible empirical proof, although I have encountered a couple of brilliant postmodern thinkers infected by the virus that questions rationality and the greatest neutral rational fact of all, eternity. As do some here.

    Rationally Europa has an immeasurably low possibility of supporting life, even if it got there as Terran extremophiles. It just doesn't have the gradients, intersections, possibility space in the most probable thick ice model, even with black smokers, but here's hoping when we finally drill through the tens of km of ice and get a sample of water back to earth. Got a spare $100 BN anyone?
  • It always strikes me that either answer should make us sit up.

    Either we are alone in the universe as a species who can produce intelligence - we are unique

    Or there are other similarly capable creatures out there.

    There is every evidence that there is other life out there. Rather, every chance that somewhere in our solar system, something might exist, and there are many other places outside.

    And we spend so much of our effort and energy killing each other.
  • Martin54Martin54 Shipmate
    It always strikes me that either answer should make us sit up.

    Either we are alone in the universe as a species who can produce intelligence - we are unique

    Or there are other similarly capable creatures out there.

    There is every evidence that there is other life out there. Rather, every chance that somewhere in our solar system, something might exist, and there are many other places outside.

    And we spend so much of our effort and energy killing each other.

    We've had the answer since Anaximander and other pre-Socratics, not just Charles Lyell.
  • Why does life have to rely on oxygen ? We have sulfur reliant bacteria on Earth.

    (Bleuch to that spelling of sulphur, but it's now technically correct)
  • Why does life have to rely on oxygen ? We have sulfur reliant bacteria on Earth.

    (Bleuch to that spelling of sulphur, but it's now technically correct)

    I'll start spelling sulphur wrong as soon as I stop hearing "aluminum".
  • Martin54Martin54 Shipmate
    Why does life have to rely on oxygen ? We have sulfur reliant bacteria on Earth.

    (Bleuch to that spelling of sulphur, but it's now technically correct)

    It doesn't. Empirical detection of it on ambient worlds does.
  • Penny SPenny S Shipmate
    My brain, without my consciously arranging it that way, automatically assumes that sulfur is about science, and sulphur may not be, may even belong along with brimstone in totally fictional contexts.*
    (I agree about aluminum - sauce for one is sauce to the other. There was an agreement, which only one party observes.)

    For us to be the only intelligent life form in the universe is utterly improbable. Thank goodness the distances involved effectively quarantine us all from each other. Either we would behave as we have with indigenous peoples all over the planet with them, or they would do it to us.

    *Got caught out once reading an American edition of the Odyssey. I had to stop reading and recalibrate when the ship was filled with the stuff.
  • Martin54Martin54 Shipmate
    edited May 14
    Penny S wrote: »
    My brain, without my consciously arranging it that way, automatically assumes that sulfur is about science, and sulphur may not be, may even belong along with brimstone in totally fictional contexts.*
    (I agree about aluminum - sauce for one is sauce to the other. There was an agreement, which only one party observes.)

    For us to be the only intelligent life form in the universe is utterly improbable. Thank goodness the distances involved effectively quarantine us all from each other. Either we would behave as we have with indigenous peoples all over the planet with them, or they would do it to us.

    *Got caught out once reading an American edition of the Odyssey. I had to stop reading and recalibrate when the ship was filled with the stuff.

    For us to be the only intelligent life form in 10 kly is utterly improbable, as in absolutely unlikely but not empirically impossible as we can't check the billions of star systems in that bubble, whereas in this infinitesimal universe is absolutely impossible.
  • Marvin the MartianMarvin the Martian Admin Emeritus
    mousethief wrote: »
    I don’t think earth is the only place with life in the universe. Or even in our own solar system, for that matter. Every discovery made - exoplanets, organic chemistry on asteroids, etc - points further in the direction of life being quite common.

    Except for the fact of not actually discovering any.

    Not yet.
  • I thought they'd found some sort of evidence of bacteria on Mars?
  • Martin54Martin54 Shipmate
    edited May 14
    I thought they'd found some sort of evidence of bacteria on Mars?

    Uh huh. How come I don't know about this? Ohhhhhh. You mean the methane trace. Uh huh.
  • Martin54Martin54 Shipmate
    mousethief wrote: »
    I don’t think earth is the only place with life in the universe. Or even in our own solar system, for that matter. Every discovery made - exoplanets, organic chemistry on asteroids, etc - points further in the direction of life being quite common.

    Except for the fact of not actually discovering any.

    Not yet.

    We don't have to to know it's there with certitude. But empiricism is nice.
  • Martin54 wrote: »
    I thought they'd found some sort of evidence of bacteria on Mars?

    Uh huh. How come I don't know about this? Ohhhhhh. You mean the methane trace. Uh huh.

    Yes, I think that's what I meant. From Professor Go Ogle:

    Living microorganisms, such as methanogens, are another possible source, but no evidence for the presence of such organisms has been found on Mars, until June 2019 as methane was detected by the Curiosity rover.

    I shouldn't have used the word *bacteria*. My bad.
  • Marvin the MartianMarvin the Martian Admin Emeritus
    Martin54 wrote: »
    I thought they'd found some sort of evidence of bacteria on Mars?

    Uh huh. How come I don't know about this? Ohhhhhh. You mean the methane trace. Uh huh.

    The Martian methane plumes are evidence that may point towards life, yes. Not conclusive evidence, but still evidence.
  • Martin54Martin54 Shipmate
    edited May 14
    Martin54 wrote: »
    I thought they'd found some sort of evidence of bacteria on Mars?

    Uh huh. How come I don't know about this? Ohhhhhh. You mean the methane trace. Uh huh.

    The Martian methane plumes are evidence that may point towards life, yes. Not conclusive evidence, but still evidence.

    Aye, on a planet with the biggest volcano (pressure cooker valve) in the solar system where gas giants are balls of non-biogenic, primeval methane, easily produced by geologic methanogenesis.
  • Martin54Martin54 Shipmate
    Martin54 wrote: »
    I thought they'd found some sort of evidence of bacteria on Mars?

    Uh huh. How come I don't know about this? Ohhhhhh. You mean the methane trace. Uh huh.

    The Martian methane plumes are evidence that may point towards life, yes. Not conclusive evidence, but still evidence.

    Until abiotic geochemistry is eliminated as impossible to explain the trace, that's what it is.
  • mousethiefmousethief Shipmate
    mousethief wrote: »
    I don’t think earth is the only place with life in the universe. Or even in our own solar system, for that matter. Every discovery made - exoplanets, organic chemistry on asteroids, etc - points further in the direction of life being quite common.

    Except for the fact of not actually discovering any.

    Not yet.

    Argument from future discovery isn't even argument. It's just wishful thinking.
  • Martin54Martin54 Shipmate
    mousethief wrote: »
    mousethief wrote: »
    I don’t think earth is the only place with life in the universe. Or even in our own solar system, for that matter. Every discovery made - exoplanets, organic chemistry on asteroids, etc - points further in the direction of life being quite common.

    Except for the fact of not actually discovering any.

    Not yet.

    Argument from future discovery isn't even argument. It's just wishful thinking.

    We don't need to discover any to know that they are there as they always have been.
  • Penny SPenny S Shipmate
    Actually, I have been reading about this very issue in "The Human Cosmos -see what we are reading thread.
    The Allan Hills meteorite which turned out to be from Mars, and others since identified as from there (ejected by impact) contain carbonate structures, very small, which are similar for organically produced structures in Earth rocks. They also contain chemical traces suggestive of life. I was under the impression that they had now been discounted, so the report in the book may possibly not be up to date.
  • Martin54Martin54 Shipmate
    Penny S wrote: »
    Actually, I have been reading about this very issue in "The Human Cosmos -see what we are reading thread.
    The Allan Hills meteorite which turned out to be from Mars, and others since identified as from there (ejected by impact) contain carbonate structures, very small, which are similar for organically produced structures in Earth rocks. They also contain chemical traces suggestive of life. I was under the impression that they had now been discounted, so the report in the book may possibly not be up to date.

    All claims had been debunked by 2001, 'the scientific consensus is that "morphology alone cannot be used unambiguously as a tool for primitive life detection."'.
  • Merry VoleMerry Vole Shipmate
    edited May 16
    pondering on the OP re 'God creating other creatures with their own special relationship to Him'. Firstly, I think God has a 'special relationship' with all creatures on earth, not just humans. Unless one is a Young Earth Creationist we presumably believe all life is linked, all the way back to 'Primordial Soup' or however life began. But I guess the OP was referring to a 'special relationship' God has with humans -partly at least because God chose to be incarnated as a human being.
    Is our human relationship with God one predicated on intelligence? In other words does degree of intelligence affect or determine the ability to have a relationship with God?
    I would say not, as the relationship is initiated by God , rather than the other way round.

    Although I don't agree with posters who believe in the inevitability of other intelligent life in the universe, it is still interesting to speculate what it would mean for what we on earth believe about life and God.
    What if a life form somewhere else in the universe, had evolved that was far more intelligent than us? Would they look after each other and their world better than we humans do? Would they then have a different type of relationship with God than we do?
    I have always thought that the human failings that God works to solve with the gospel were moral failings. But what if they are failings of intelligence? *


    * (which reminds me of the quote 'If you think education is expensive, try ignorance!'
    (- although that begs the question of whether education improves intelligence or not!)
  • Marvin the MartianMarvin the Martian Admin Emeritus
    mousethief wrote: »
    mousethief wrote: »
    I don’t think earth is the only place with life in the universe. Or even in our own solar system, for that matter. Every discovery made - exoplanets, organic chemistry on asteroids, etc - points further in the direction of life being quite common.

    Except for the fact of not actually discovering any.

    Not yet.

    Argument from future discovery isn't even argument. It's just wishful thinking.

    I’m arguing from current knowledge based on historical discoveries which, while not offering any kind of conclusive proof of life elsewhere, can certainly be taken as pointing in that direction.

    A decade ago I could have said I believed the Higgs Boson existed based on the extent of scientific -knowledge at the time. And you could have said “we haven’t seen it, so it doesn’t exist”. Which of us would have been more justified?

    Did the planet Neptune exist before 1846? Would you have dismissed earlier predictions of its existence derived from orbital anomalies in the other planets on the grounds that we haven’t seen it?
  • Martin54Martin54 Shipmate
    Merry Vole wrote: »
    pondering on the OP re 'God creating other creatures with their own special relationship to Him'. Firstly, I think God has a 'special relationship' with all creatures on earth, not just humans. Unless one is a Young Earth Creationist we presumably believe all life is linked, all the way back to 'Primordial Soup' or however life began. But I guess the OP was referring to a 'special relationship' God has with humans -partly at least because God chose to be incarnated as a human being.
    Is our human relationship with God one predicated on intelligence? In other words does degree of intelligence affect or determine the ability to have a relationship with God?
    I would say not, as the relationship is initiated by God , rather than the other way round.

    Although I don't agree with posters who believe in the inevitability of other intelligent life in the universe, it is still interesting to speculate what it would mean for what we on earth believe about life and God.
    What if a life form somewhere else in the universe, had evolved that was far more intelligent than us? Would they look after each other and their world better than we humans do? Would they then have a different type of relationship with God than we do?
    I have always thought that the human failings that God works to solve with the gospel were moral failings. But what if they are failings of intelligence? *


    * (which reminds me of the quote 'If you think education is expensive, try ignorance!'
    (- although that begs the question of whether education improves intelligence or not!)

    It's not just the absolute certainty of shared intentionality elsewhere in the galaxy, let alone by the trillions of species elsewhere in this insignificant universe, it's the infinity of such species there has been in the infinity of universes for eternity. That can't be rationally disagreed with on any basis whatsoever. So on what basis do you disagree?

    I don't see higher intelligence fixing our moral limitations in the slightest. Why would higher intelligence predispose a species to be more caring? If the average human had an Einsteinian level intelligence, had the ability to understand Kant at 13, would emotional intelligence follow? Why would evolution select for that, with the opportunity costs that come with it?
  • Merry VoleMerry Vole Shipmate
    I'm not saying evolution *would* select for that, just that it *could* or just might..
    I'm not an expert on evolution, but I think there is no inevitability of life evolving to produce consciousness and human-level intelligence. Evolution goes in the direction the environment allows.
  • Martin54Martin54 Shipmate
    Merry Vole wrote: »
    I'm not saying evolution *would* select for that, just that it *could* or just might..
    I'm not an expert on evolution, but I think there is no inevitability of life evolving to produce consciousness and human-level intelligence. Evolution goes in the direction the environment allows.

    Absolutely, but it accumulates, complexity increases, it 'learns'. And on a galactic scale at least, the inevitable has happened. Here we are. Nowt special. There is no rational reason to believe that the trillion worlds of our galaxy are sterile and that at least the next order of magnitude to us, ten of them don't have concurrent civilizations to ours. Ten thousand. A million.
  • Martin54 wrote: »
    Merry Vole wrote: »
    I'm not saying evolution *would* select for that, just that it *could* or just might..
    I'm not an expert on evolution, but I think there is no inevitability of life evolving to produce consciousness and human-level intelligence. Evolution goes in the direction the environment allows.

    Absolutely, but it accumulates, complexity increases, it 'learns'. And on a galactic scale at least, the inevitable has happened. Here we are. Nowt special. There is no rational reason to believe that the trillion worlds of our galaxy are sterile and that at least the next order of magnitude to us, ten of them don't have concurrent civilizations to ours. Ten thousand. A million.

    I expect you're right - nay, I hope you're right - but we simply don't know for absolute certain...

    We can have some fun speculating, of course!
  • Martin54Martin54 Shipmate
    Martin54 wrote: »
    Merry Vole wrote: »
    I'm not saying evolution *would* select for that, just that it *could* or just might..
    I'm not an expert on evolution, but I think there is no inevitability of life evolving to produce consciousness and human-level intelligence. Evolution goes in the direction the environment allows.

    Absolutely, but it accumulates, complexity increases, it 'learns'. And on a galactic scale at least, the inevitable has happened. Here we are. Nowt special. There is no rational reason to believe that the trillion worlds of our galaxy are sterile and that at least the next order of magnitude to us, ten of them don't have concurrent civilizations to ours. Ten thousand. A million.

    I expect you're right - nay, I hope you're right - but we simply don't know for absolute certain...

    We can have some fun speculating, of course!

    We can never know empirically, and we already know rationally. That's all we need.
  • Gramps49Gramps49 Shipmate
    edited May 16
    CBS Sunday Morning ran this video today https://www.cbsnews.com/video/something-in-the-air-the-increased-attention-to-ufos/

    Concerning the recently reported discovery of bacteria Mars, the guess is the instruments may have been contaminated before launch. More investigation to follow.
  • alienfromzogalienfromzog Shipmate
    And so we have arrived at the Drake Equation.

    Wiki article here: https://en.m.wikipedia.org/wiki/Drake_equation

    Two thoughts:
    1. I am a big fan of the Drake Equation as a rational way to consider this question.
    2. My conclusion is that we probably are alone in the universe. I think that people who draw the opposite conclusion are underestimating how complex life is and thus overestimating the probability of life arising on any putative planet that is hospitable to life.

    So, let's look at Drake:
    N = R*fpneflfifcL

    Where:
    N = the number of civilizations in our galaxy with which communication might be possible (i.e. which are on our current past light cone);
    and
    R* = the average rate of star formation in our galaxy
    fp = the fraction of those stars that have planets
    ne = the average number of planets that can potentially support life per star that has planets
    fl = the fraction of planets that could support life that actually develop life at some point
    fi= the fraction of planets with life that actually go on to develop intelligent life (civilizations)
    fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
    L = the length of time for which such civilizations release detectable signals into space

    There is obviously a lot of speculation here because of the huge range of values for each variable. However, one of the interesting things is we now know R*, fp and ne with a fair degree of certainty. The Wiki article links to recent data that puts the number of new stars at between 1.5 and 3 per year, the fraction of stars with planets at approaching 1 (i.e. stars having planets is a rule rather than an exception) and the fraction that could potentially support life at 0.1 (i.e. 10%).

    Therefore if fl, fi, and fc have high values then N is going to be high and thus we know that it's a statistical certainty that there is intelligent life out there in our galaxy. Indeed original estimates put these fractions as essentially 1 in each case. Thus we would expect a civilisation we could communicate with for every 3-5 years that the galaxy has existed (multiplied by the longevity of these civilisations); i.e. the universe would be literally teeming with species for us to meet (i.e. Star Trek!)

    However, I don't think that. I think life is really rare in our galaxy because I think fl is actually really low. Life is really complicated stuff. The argument for a fl approaching one is based on the fact that life seems to have appeared on earth almost as soon as the conditions were conducive to it. Obviously, this is an anthropomorphic view and thus potentially problematic but also life only arose on earth once. We only have carbon-based lifeforms on this planet (that we've found so far!). By which we mean that all of the key molecules that make up our bodies are carbon compounds. There are some very good chemistry reasons for this; the fact that carbon forms four covalent bonds and that these are stable with nitrogen and oxygen and phosphate and hydrogen and a few others is key to making life possible. The next nearest element is silicon. Which is why it's a cliche of Sci-Fi to talk about silicon-based lifeforms but as far as we can tell, it doesn't quite work. Obviously in a wide, wide universe, all sorts of things might be possible that we don't yet know about but this is but a marginal addition to the probability. We do know a lot about what is needed to make Carbon-based life work.

    Obviously, this gets a bit metaphysical and philosophical because the very definition of life is a little tricky but we can narrow it down a bit to self-replication of a genome. And here, by genome, I mean some sort of molecule that carries the coded information for life. In our experience of earth-organisms this can only mean DNA (or RNA*). DNA is a very big carbon compound.

    So, what's the minimum number of genes you need to make life as we know it? Well, it's a few. For the sake of simplicity, I will suggest an organism that is a single cell. Has a genome (made of DNA) and uses protein enzymes to work. That's a simplistic description of all life of planet earth (as far as we know). Now the reason I have said DNA for the genome is that there is no known complete organism that has an RNA genome (RNA is not as stable as DNA). There are RNA viruses but they are not self-sufficient and rely on other organisms in order to replicate).

    So, what does our simplistic organism need? Well, It needs an enzyme for copying the DNA (i.e. to make new organisms!) It needs an enzyme to make RNA copies of each gene in order to make the proteins in needs to run the cell. It needs ribosomes (this is the key cell machinery that builds proteins from amino acids) It needs a gene to make the tRNA molecules that bring the amino acids together to make the proteins. It needs an enzyme for building the phospholipid membrane that makes the cell wall. It needs an enzyme for using energy and it needs at least one protein to make a channel in the cell wall for allowing it to capture nutrients from its environment. By my count, that's a minimum of 7 fully functioning genes to make a very primitive cell. In reality, what I've described is ridiculously over-simplistic and would not even come close to be a viable life form. The least number of genes of any known organism is 525 genes!

    (There has been some interesting work in this area: see here: https://www.discovermagazine.com/planet-earth/biologists-create-organism-with-smallest-genome).

    Hopefully, I am beginning to get across, just how complex abiogenesis (life starting) is. The mathematical probability of generating some sort of functioning organism, even on our putative favourable planet is very, very small. Evolutionary theory would suggest that once you get a functioning genome, then single-cell organisms will lead to complex organisms and intelligent life if you give it long enough, but you have to get started first!

    <continued below>
  • alienfromzogalienfromzog Shipmate
    <continued>

    The mathematics here might not be very intuitive but it is simple. The argument goes: there are billions of planets capable of supporting life in the known universe, therefore there must be life out there somewhere! But if the probability of life starting is very, very small, that doesn't hold. Let's propose 1 billion planets capable of supporting life. If the probability of abiogenesis is 1 in 1000 then of those billion planets, only 1 million will have life. If it's 1 in a trillion then the odds are 1000/1 that any of them will have life!

    My point is that molecular biology in the past 20 years has shown that life is even more complex than we thought it was. Now, one might argue that we have billions of years of evolution to develop that complexity which is true. But, even the most primitive of life is actually pretty darn complex thus the fl is probably very, very, VERY small. If the probability of life arising on a particular planet (that is indeed favourable to life) is say 1 in 10100 (and I can easily construct probability estimates that go this high) then the fact that there are thought to be 10,000,000,000,000,000,000,000,000 planets in the known universe does not help you very much as that's only 1025 and thus the odds of there being life on any of them would be 1 in 1075. by comparison your odds of winning the lottery are only 13 million to one! (i.e. 1.3 x 107). YMMV.

    Of course, I could be completely wrong. I may be massively overestimating how complex the most primitive form of a cell might be that's needed to get life going in the first place. However, 525 genes is a helluva lot to get in order to just have a single cell that's capable of replicating itself. I think that the problem is that astrophysicists get really excited about how big our universe is and haven't noticed how the mathematics of even simple lifeforms cuts in completely the other direction...

    So, yeah, on balance, I think we probably are alone in the universe (my name notwithstanding).


    AFZ


    *There are no known-RNA organisms that are not obligate intracellular parasites and thus depend on DNA organisms to replicate. All of this is speculation but in the absence of a viable model, life (but not as we know it Jim) is even less likely than life as we know it.
  • alienfromzogalienfromzog Shipmate
    I appreciate that that is far, far too long so here's the short version: TL:DR...

    Are we alone in the universe?

    Probably.

    AFZ
  • Bishops FingerBishops Finger Shipmate
    edited May 16
    I appreciate that that is far, far too long so here's the short version: TL:DR...

    Are we alone in the universe?

    Probably.

    AFZ

    :lol:

    Well, you got here all the way from Zog, so no, we aren't alone...
  • mousethiefmousethief Shipmate
    mousethief wrote: »
    mousethief wrote: »
    I don’t think earth is the only place with life in the universe. Or even in our own solar system, for that matter. Every discovery made - exoplanets, organic chemistry on asteroids, etc - points further in the direction of life being quite common.

    Except for the fact of not actually discovering any.

    Not yet.

    Argument from future discovery isn't even argument. It's just wishful thinking.

    I’m arguing from current knowledge based on historical discoveries which, while not offering any kind of conclusive proof of life elsewhere, can certainly be taken as pointing in that direction.

    A decade ago I could have said I believed the Higgs Boson existed based on the extent of scientific -knowledge at the time. And you could have said “we haven’t seen it, so it doesn’t exist”. Which of us would have been more justified?

    Did the planet Neptune exist before 1846? Would you have dismissed earlier predictions of its existence derived from orbital anomalies in the other planets on the grounds that we haven’t seen it?

    And what evidence do we have for extraterrestrial life that even comes close to orbital anomalies, which are measurable and must needs have a physical cause?
  • Martin54Martin54 Shipmate
    I appreciate that that is far, far too long so here's the short version: TL:DR...

    Are we alone in the universe?

    Probably.

    AFZ

    1 in 1,000,000,000,000,000,000,000,000 worlds. Riiiiiiight.

    So are we alone in all of eternal infinity too?
  • alienfromzogalienfromzog Shipmate
    edited May 16
    Martin54 wrote: »
    I appreciate that that is far, far too long so here's the short version: TL:DR...

    Are we alone in the universe?

    Probably.

    AFZ

    1 in 1,000,000,000,000,000,000,000,000 worlds. Riiiiiiight.

    So are we alone in all of eternal infinity too?

    Given that most astrophysicists think the universe is expanding (since the Big Bang) and therefore finite, I don't have that mathematical problem...

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