Chance of life on other planets

Discussion in 'Astronomy, Exobiology, & Cosmology' started by James R, Sep 4, 2010.

  1. jmpet Valued Senior Member



    N = the number of civilizations in our galaxy with which communication might be possible;

    R* = the average rate of star formation per year 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 the above that actually go on to develop life at some point
    fi = the fraction of the above that actually go on to develop intelligent life
    fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
    L = the length of time such civilizations release detectable signals into space.[3]

    N = 7 × 0.5 × 2 × 0.33 × 0.01 × 0.01 × 10000 = 2.31
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  3. birch Valued Senior Member

    this analogy doesn't work because the egg must have been consciously placed in the boxes. the chance of life on other planets is not based on a arbitrary act.
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  5. Green Destiny Banned Banned

    Oh, I disagree.

    In this specific case, if life had been consciously placed on a series of planets spread throughout the universe, it certainly would not be an arbitrary fact. It would instead, invoke some idea of an intelligent creator, or, a creator with intent.
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  7. Green Destiny Banned Banned

    sorry, had to edit the message. I meant ''not be''.
  8. birch Valued Senior Member

    this topic has nothing to do with a creator with intent.

    my post was specifically addressing the analogy.
  9. Green Destiny Banned Banned

    Remember what the analogy stands for. You are taking what has been proposed - a conscious decision to place eggs in boxes - the analogy of this is of life on planets. I was just taking your example further through logic, what the analogy truely means, and in the case, it would suggest an intent where life was placed in the universe if indeed there was a conscious decision.

    Don't worry, I'm not straddling down religious intent, I was following on your words with logic, and replacement of what the analogy truely meant.
  10. Shadow1 Valued Senior Member


    a question:
    may be their a chance, that there's other humans like us, somewhere else in the univerce?
  11. Green Destiny Banned Banned

    The statistics of an occurrance far outweigh the age itself of the universe, that is, if we are to suspect this ''other human likeness'' is totally independant to our civilizations existence. However, if that were to be true, then it may happen in an alternative way through Panspermia Theory. The chances would considerably increase to believe that another human-like exocivilization existed, for it's possible microbes could have been transported from planet to planet, so something genetically-similar may arise in that aspect. Of course, they wouldn't be dopplegangers, only an evolutionary course.
  12. Shadow1 Valued Senior Member


    just a question, how exactly, does evolution, works? and why? and what's it's purpose? it can't be for nothing. and how does it do it? and how does it make the changes? and how does it choose to keep things and change things? and why all that?
  13. Green Destiny Banned Banned

    I could take a very Darwinian-Approach, but as many do realize, concepts like survival of the fittest, are incomplete. There seems to be an inherent, deeper meaning to the ''survival of the fittest'' idiom.

    It seems, that the very nature of life, is to simply live it - whether you are chosen naturally to be able to survive or not. Natural selection however, is a very misdomeaning word, there is nothing consciously-selective about the processes, if it is natural.

    Therefore, it would seem that natural selection is a random set of events which are natural by definition, meaning that pertain to natural laws. These laws may not have a broad and vast band of reason over the many ecosystems which now infestate the world over, but, nevertheless, all the life does share one common-instinct, and that is the drive to live.

    Natural selection is no more a faulty misuse of words, than what we might expect from the term survival of the fittest. It seems that life has it's place, without there necesserily being anything like a gradient in all life where there is a specific fittest catagory.

    Life simply is, because it can, and will grow and mutate, because that is the prime function of all life, from the micro-organism, to the great Leviathon.
  14. Sarkus Hippomonstrosesquippedalo phobe Valued Senior Member

    James, to add my tuppence...

    If there is no relationship between the nature of the box and the existence / non-existence of an egg, then based on our existing knowledge we would estimate 10 of the 100 boxes to have an egg.
    With each new piece of information (e.g. opening another box) the estimate would change.
    For example, if we had not yet opened any other box then we the rationally conclude that each box contains an egg.

    If, on the other hand, each box is slightly different, then our estimate would depend upon our views of how/whether the nature of the box relates to the existence of an egg.

    Alternatively, if we are of the assumption that an unknowable external consciousness put the eggs in the boxes, and that the existence of an egg in a particular box is entirely and wholly at the whim of the external consciousness, then I would conclude that it is not possible to know how many boxes have eggs.
  15. birch Valued Senior Member

    the analogy doesn't work at all because there is no way to know or even guess how many eggs exist in any box based on this information alone simply because the egg in a box makes no sense whatsoever. an egg isn't simply going to exist in a box unless someone put it there either by mistake or by conscious choice. there is also no indication of a pattern anyways so far.

    either way, life on other planets has to do with the laws of the universe which we have more information about which suggests a pattern from cause and effect along with the law of probability. there is no real cause and effect in the egg/box analogy.
    Last edited: Sep 5, 2010
  16. lightgigantic Banned Banned

    I disagree

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  17. birch Valued Senior Member

    this analogy is similar to what happened when i moved. there was one box that was teeming with ants and found out that it was a piece of chocolate in the box by accident. none of the other boxes had chocolate.

    it's an accident because it was not meant to be packed. secondly, the packing box would not spontaneously produce chocolate as it's unrelated in that context.
  18. Green Destiny Banned Banned

    I do not believe James wanted the analogy to be taken in the superfluously-serious context, but as a shadow of a more amusing anecdote to an oversimplified example of something otherwise greately complex.
  19. M00se1989 Banned Banned

    I believe it is increasing exponentially as time passes that we will either find or occupy another planet. mars so far is looking like the best option.
  20. nietzschefan Thread Killer Valued Senior Member

    Frankly the fact that life may have existed to some degree on Mars(when it was water rich) and probably exists on EUROPA at a tiny level, really should put the life in the universe - pessimists, in their place. That's 3 places just in our solar system.
  21. Green Destiny Banned Banned

    Good point.
  22. James R Just this guy, you know? Staff Member

    Some interesting and thoughtful responses.

    My own answer to my analogy is that we simply don't have enough information to estimate the number of boxes that contain eggs.

    What do we know? Only that 1 box out of 100 contains an egg and 9 do not. There are 90 unknown boxes left.

    We don't know whether eggs were placed at random or according to some scheme. We don't even know whether some boxes are more conducive to having eggs than others.

    In terms of trying to estimate the chances of life on other planets, we can perhaps do a bit better. We have some idea about the conditions that are conducive to life. However, we aren't at all sure about the chance of life developing even if the conditions are conducive.

    I think the analogy is potentially useful in exposing some muddy thinking. We currently know of one planet that has life on it. From that piece of data alone, it is very hard to estimate the probability of life elsewhere.

    Things could get a lot better, though. Suppose we find that Mars has indigenous life on it. Then we'd have two examples of life in our our solar system alone. It seems to me that the chances would then be very good for life elsewhere, even intelligent life. This is where the analogy with the eggs breaks down significantly, because of our far greater knowledge of the conditions under which life is likely to thrive, as compared to the conditions under which eggs are likely to be found in boxes.


    Comments on the answers other people have given above:

    Yes, but you have assumed that the chance of any box containing an egg is the same for all boxes.

    I agree.

    No, I don't assume that.

    Exactly right.

    100 boxes, 1 trillion boxes - it makes no difference.

    • What are the assumptions of the Poisson distribution? (I can't recall, but there's some randomness there, isn't there?)

      It's strange how I can make an error just by asking a question. :shrug:

      So, before the discovery of the platypus and the echidna, it would have been correct to assume that egg-laying mammals did not exist, according to you, even though such a thing is clearly possible.

      I didn't give any information on whether the placement of eggs was arbitrary or not.

      It's interesting to compare this to the contemplation of life elsewhere. In fact, the general assumption before any extraterrestrial bodies were explored, was that life would be found everywhere. I'm not convinced this is a reasonable position to take, even if it is rational.


  23. IamJoseph Banned Banned

    I will make a pointer which is very hedy and difficult to explain, but I will try. It will show the insanity of NS as most understand this.

    Imagine light per se is point A, the sun is point B, the earth is point C, D is the environment and life is point E.

    Here, ToE is saying that E comes from D and/or point B [whichever or combined does not matter].

    But to have point B and D, there has to be A as pre-existant. The sun could not produce light without A; the D would have no effect without A.

    When we say life emerged, we are saying it emerged from somewhere - its essence must be pre-existing as a concept - even if it is derived from a combination of multiple factors.

    When we say life emerged in the universe - we are saying the life pre-existed the universe in some form [potentially, or as a program or law], and that the universe came [proceeded] to life; this is true even if the life appeared by later interactions in the universe: the life could not emerge unless it was existant in some form as a premise.

    Another example: the universe was created in wisdom. This means wisdom pre-dated the universe.

    Again. Toyota made a car. This means the premise of a car predated Toyota making the car.

    Again. Jack built a home. The premise of 'HOME' [blueprints] preceded the home.

    Here, even science is an after thought - the premise of science [laws] must be precedent - namely the factor of the formless becomeing form must be first.

    The environment selecting life on its own is wanting. Think it over and be sure before responding.

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