Chance of life on other planets

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

  1. nietzschefan Thread Killer Valued Senior Member

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    Ya Told ya so.
     
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  3. keith1 Guest

    Yeah, this is a cheap penal colony that can't afford guards.
     
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  5. Me-Ki-Gal Banned Banned

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    5 is my guess . There may be non , but my brain tells me there may be 5,, any more and I would be surprised. My law of diminished returns tells me not to bet any money on the other boxes having an egg
     
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  7. orcot Valued Senior Member

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    Hey it makes the drake equision a little more interesting

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    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

    Turns to R*xfpXne could be a min of 100 000 000-500 000 000 planets depending witch article you read
    500 mil planets
    100 mil planets.

    leaving the drake equision as only:

    fl = 1 (100% of these planets will develop life)
    fi = 0.01 (1% of which will be intelligent life)
    fc = 0.01 (1% of which will be able to communicate)
    L = 10,000 years (which will last 10,000 years)


    N= x00 000 000*fl*fi*fc*L

    It is however still a guessing game
     
  8. keith1 Guest

    Earth-like conditions, algae and time. If it can walk out of the water, it will walk into Cambridge.
     
  9. orcot Valued Senior Member

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    I would say the changes for a earthlike planet with a earthlike temprature and at least some water the changes for life to develop are nearly 100%. However their seems to be a large change that it stays with that and never develops beyond single cell organism.
    I also do not believe that every sentient species will evolve to the point of inventing the wheel or metalurgy or even simple farming like the neanderthals who seems were probably as smart as us.
    That said a single sentient species must be very rare in the universe it should either be none or something in the order of 2-5 or so
     
  10. Dinosaur Rational Skeptic Valued Senior Member

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    The recent data relating to planets is not startling. Long before there was observational evidence, there werre reasons to believe in the existence of a huge number of planets.

    I wish people would put the Drake equation to rest. Analysis of the development of life on earth is a better approach to the problem than guessing at parameters for the Drake equation.

    BW: The original concept of this thread is not a good analogy to the problem of estimating the existence of life eslewhere. We only have a sample of one, but the sample of life on earth comes with a huge amount of information relating to the the history of life on earth. In addition there is a huge amount of relevant data about the rest of the cosmos. Finding one egg in some number of boxes comes with almost zero data useful for estimating the chances of other eggs.
     
  11. keith1 Guest

    Your pulling that data out of your magic hat? I would agree with you if there was no life anywhere in the universe. But there is. I'm an example, standing here posting to an example.

    (To add: It is been noted that on Earth, one is never more than six feet away from an insect).
     
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  12. keith1 Guest

    Unless that one doing the finding of the egg, is an egg-layer itself. Then one must logically advance the odds.
     
  13. Believe Happy medium Valued Senior Member

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    simple life 100% chance

    something like us ???% chance. It's probably out there but it could be waaaaayyyyyyyy to far away to matter or of us to ever detect it
     
  14. orcot Valued Senior Member

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    Odd remark if I reply on a post of their being 500 million earth like planets (your post by the way) and add a other article of a 100 million possible earth like planets in "the habitable zone" I can't imagen what part of it could have been misintripited that their is no life in the universe?

    And abouth the actual quote that I found it odd that only 1 sentient species lives on a single planet you have to admit with the biodiversity here on earth 1 of anything is extremly rare.
    For comparison:
    The gorilla:
    you have the gorilla gorilla gorilla (I wouldn't try to say that in a mirror)
    but you also have the rilla gorilla diehli a subspecies
    chimpanzees:
    has Pan troglodytes and Pan paniscus

    I could go and name pretty much all the great apes but when you come to humans (homo sapiens) their is only one and that is pretty rare (not a unicum either).

    I yust remarked that on a alien planet a sentient being might arise out of evolution and altough it's biology might be completly different than ours the same principles of evolution exist meaning X out of X changes it will have evolutionary cousins meaning more than 1 sentient species on their planet.


    I hope I made myself a little more clear by this
     
  15. keith1 Guest

    Or not. Your stance has been easily neutralized. Without the extra symbolic superlatives, I might add.
     
  16. keith1 Guest

     
  17. orcot Valued Senior Member

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    agree
    This being the 500 million as you said on page 11 refering to this article?
    well I wouldn't say that 500 million is a low numbre but I put in the drake equision to show that a earthlike planet in the "goldilock zone" not to hot not to cold doesn't immediatly that their is sentient life with the conclusion that it is still a guessing game.

    I'm not entirly following but yes sometimes some species go extinct and it's almost unavoidable. It could be that you are trying to say that one sentient species will always try to kill the other sentient species. And yes people these days do exterminate other species but we mainly do it by modifying the landscape, before that we more or less scavengers and we have been known to domesticate animals meaning if it ain't harmful and it's useful we adopt it. Did we kill the other sentient species? Who knows? But their gone nonetheless.

    I do agree most planets with life on will not have intilligent life on it but if their is intliligent life on it then the story changes it will have subspecies homo sapiens alone has quit a few (all extinct offcourse). Any alien species will have a somewhat similar history I'm yust saying hey what if on this alien world all those species are alive their would be 5 species with a cranial capacity 2 times bigger then a gorilla.

    Let's look at it a different way if you went back in time 170 000 years ago then apart from humans (homo sapiens sapiens)
    you would also have neanderthals, idaltus, rhodesiensis and heidelbers you can argue if these species were really intilligent but the all wore clothes and had fire.

    That said going from the quistion is their life in the universe, to is their intilligent life in the universe, I also like the add the quistion is that intilligent alone.

    If anything human history showed us that both are possible
     
  18. keith1 Guest


    From the link: "...And that's a minimum (500 million habitable zone planets) because these stars can have more than one planet and Kepler has yet to get a long enough glimpse to see planets that are further out from the star, like Earth..."

    I interpret that statement as that, to date, habitable zone planetary finds have been mostly in the extreme inner habitable region, where technology is easiest to pinpoint and resolve. That much work is to be done in exploring the zone areas as far out as relates to the distance Earth is from our star.
    500 million is a low estimate.

    No other sentient being survived on Earth to invent rockets, nor may have had the capability to ever do so (from the fossil record), with even some kind intervention.

    Rockets were invented on arrows (India/Asia) and developed further in Germany. both for warfare purpose.
    Warfare may be an invention of isolated (Geologic/Mountain Ranges) cultures separated by distance, and forced to later clash, after stress of cultural incompatibility.

    Reasoning then, such other planetary cultures found, would greatly match our own need to make rockets, if such geologic impediments were also found on the surface of their planet. We would know them by their geology.
     
  19. D H Some other guy Valued Senior Member

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    2,257
    That is your math. Others have different math.

    I tend to agree with Dinosaur here. The Drake equation was something cooked up by Sagan and Drake after one too many puff. Depending on how you spin the numbers, even with the planet estimates coming from Kepler, yield anywhere from millions of sentient, space-capable species in this galaxy alone to fewer than one such species (on average) per supercluster. In short, the Drake equation is useless.
     
  20. keith1 Guest

    I'm not saying it's useless. R is calculated by observation, and the other factors are not; fp and ne are obviously underestimated. But that only bolsters the odds that the other factors are also underestimated. Not in any way over-estimated. These factors are not in stone, but high fp and ne numbers are going to be essential indicators...

    And I managed to let the data say that...not demonizing Sagan and Drake to bolster my point.

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  21. James R Just this guy, you know? Staff Member

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    D H:

    Maybe; maybe not - how it was cooked up is irrelevant.

    No. The Drake equation is perfectly valid. The problem is that the factors in the equation are damned difficult to pin down accurately. That's due to our current state of knowledge, and is not a problem with the equation itself.
     
  22. Mircea Registered Member

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    70
    They're both idiots, so what did you expect? I mean his Spectacular Excellency the Most Fantastic Preeminent Being On-High Doctor Carl Sagan was the moron standing on Jimmy Carter's desk in the Oval Office screaming that glaciers would be cruising down Pennsylvania Avenue by the year 2000 if Carter didn't do something now! (and "now" was 1978).

    It's 2011, see any glaciers yet?

    Not only is it useless, it isn't even based on logic, reason or science.

    If you're looking for advanced multi-cellular life, then you're looking at G-Class star systems and perhaps K-Class since they're similar to G-Class.

    If you're looking for any form of life, then those star class and F and M Classes as well. You can forget about A, B and O Classes due to the rare chance of planets and the solar radiation is horrendous, even in the so-called "habitable zone."

    Why would you want to demonize His Excellency the Preeminent Foremost World Renown Authority On-High Doctor Carl Sagan?

    His rotting corpse should be dug up, drawn, quartered and burned.

     
  23. Dinosaur Rational Skeptic Valued Senior Member

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    Instead of just expressing opinions & guessing at parameters for the Drake equation, why not try an analytical approach to the subject of intelligent life elsewhere in the universe? The only evidence on which to base an analysis is the history of the Earth and our knowledge of how solar systems form. Consider the history of our planet, which contains the only evidence we have for the existence of life in general and for intelligent life in particular. Imagine compressing the history of the Solar System into 1000 days. This is easier than comparing billions, hundreds of millions, et cetera.


    Solar system formed 1000 days ago (4.6 billion years)
    First life appears 804 days ago (3.7 billion years)
    First vertebrates (fish) 87 days ago (400 million years)
    Dinosaurs appear 54 days ago (250 million years)
    First mammals 47 days ago (210 million years)
    Dinosaurs disappear 14 days ago (65 million years)
    First primate 13 days ago (60 million years)
    Early human ancestor 40 hours ago (7 million years)
    Early genus homo 10 hours ago (2 million years, Homo Erectus)
    Modern man appears 60 minutes ago (200,000 years)
    Start of civilization 3 minutes ago (10,000 years)
    Modern technology 2 seconds ago (100 years)​
    I do not claim that the above are precise values, but they are fair approximations. There is controversy over most of these numbers, so precision is not possible.

    A Scientific American fom the October 2001 issue discussed the GHZ (Galactic Habitable Zone) suitable for the development of life. The article concludes that complex life forms are rare in our galaxy.
    A solar system too close to the center of the galaxy is not likely to harbor any complex life forms due to orbital instabilities (caused by rapidly moving stars), too much radiation (due to massive stars & activity of the central black hole), and cometary/asteroid impacts (due to more objects in the Oort Cloud & Kuiper belt, as well as more disturbances of those regions caused by nearby stars).

    A solar system too far from the galactic center will not have sufficient heavy elements, which are necessary to living organisms. Elements other than hydrogen and helium are created by stars which go nova at the end of their life cycles. In particular, type II novae are required for the creation of many of the heavier elements. In the outer part of the galaxy, there have not been enough nova events to create the abundance of heavy elements required by life forms.

    The above considerations limit the GHZ to a narrow ring near the position of the solar system (about 28,000 light years from galactic center).​
    The following analysis is based on the above information.

    Life occurred on Earth not long after suitable conditions for its existence occurred. This strongly suggests that life is very likely to occur whenever conditions are suitable for its existence. Now consider the requirements for the evolution of intelligent life.

    Our solar system started to form from a collapsing cloud of interstellar dust about 5 billion years ago. It has existed in its present form for about 4.6 billion years. This suggests that a solar system requires a stable region of a galaxy for about 5 billion years, which seems to be the length of time required for the formation of the system & the evolution of intelligent life. The inner regions of a galaxy do not provide a stable region for that period of time.

    The first solar systems to form consisted almost entirely of hydrogen & helium, lacking the heavier elements required by life forms. The first stars existed in the inner part of galaxies, far from the galactic habitable zone. Stars with sufficient heavy elements might not have formed in the habitable zone for the first 1-2 billions years after the Big Bang (This is a guess on my part: I could find no estimates by expert astrophysicists/cosmologists, which I am not).

    The above supports the notion that the first intelligent life could not have come into existence until about 6-7 billions years after the Big Bang.

    BTW: The formation of a solar system seems to require a nearby nova or other event causing increased density of part of an interstellar cloud of gas. The increased density initiates gravitational collapse resulting in the formation of a solar system. In some galaxies, including our own, the first intelligent life might not come into existence as soon as 6-7 billion years after the Big Bang.

    Note that dinosaurs existed for about 185 million years, were revolutionarily successful, & were not much (if any) more intelligent when they went extinct. This strongly suggests that intelligence is not an inevitable result of evolution.

    Note that the Neanderthals were about as intelligent as our primate line, but did not survive to develop a technological culture. While some believe that we killed them off, it seems mor likely that some behavioral traits prevented them from coping with a changing environment.

    BTW: Recent DNA analysis indicates that there was some breeding between Neanderthals & our ancestors.

    There are good reasons to believe that a primate design is a prerequisite the evolution of a technological culture. Note how long it took for the first primate to appear.

    The above analysis strongly suggests that while life is likely to be common, intelligent life is likely to be rare. Intelligent life seems to be a lucky fluke rather than an inevitable result of evolution.

    While I believe that intelligent life exists elsewhere, I consider it remotely possible that none exists. I would not be surprised to learn that none exists elsewhere in our galaxy. I would not be surprised to learn that some (perhaps many) galaxies have no technological cultures.
     

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