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life elsewhere in the universe ?

Discussion in 'After Hours Lounge (Off Topic)' started by jimmyjet, May 29, 2015.

  1. jimmyjet

    jimmyjet Producer

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    i saw this mentioned in another thread, and thought it might deserve a thread of its own


    i dont have an opinion about it, because any conclusion is based entirely on assumptions


    but because of the great distances involved, it seems highly unlikely that we would ever know about any existence of life
     
  2. Walter Kittel

    Walter Kittel Lead Actor

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    Astronomers estimate that there are one hundred billion galaxies in our universe. One estimate is that there are around 70 billion trillion stars in our universe. Obviously not all of these systems can support biological life, but with that many star systems I would say the odds are decent that life exists elsewhere.


    It does seem unlikely that we will ever obtain direct evidence of extra-terrestrial life given both the vast distances between the stars but also because of how extremely brief our existence as a species that could fathom the idea of life elsewhere is in comparison to the age of the universe. Given the span of time that encompasses the universe - hundreds, thousands of races on other worlds could have lived and died. We may be one of the first intelligent species in the universe or the latest one to the party. We don't know.


    John von Neumann proposed self-replicating robots to explore space - http://en.wikipedia.org/wiki/Self-replicating_spacecraft


    One of the arguments against the existence of intelligent life elsewhere is the absence of these robotic probes. This has been countered by others including Carl Sagan (see above link.)


    - Walter.
     
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  3. jimmyjet

    jimmyjet Producer

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    at first thought, i can see why someone would think that the likelihood of life exists or has existed, based on the number of stars in our universe.


    however, that is based upon an assumption that life occurs at a frequency greater than 70 billion trillion, for example


    and that number is so huge that it alone is incomprehensible to us - so it is natural for a human brain to assume that it is likely that life exists elsewhere


    but we have no idea as to what that real frequency actually is - in other words, how often does our universe spawn conditions such that life begins ?


    if it takes on the average a gazillion gazillion stars such that life on a planet will arise, then 70 billion trillion is a drop of water in the ocean - so it all depends upon an assumption about something for which we have absolutely no facts or evidence.


    as far as the self replicating robots, i think a much simpler explanation can suffice - it would still take these robots to go out into space travel - the time it would take to travel the distances they would need to go in a universe that is expanding rapidly - just how far could any of them really go, in relation to the size of the universe ?


    many scientists already think that the majority of the universe is forever beyond our reach - i have heard the numbers as great as a penny (our visible universe) on a football field (size of actual universe)
     
  4. Dr Griffin

    Dr Griffin Cinematographer

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    The dinosaurs lasted so long because they lived in harmony with their environment. Man won't come close. Man uses for his own gain, and most certainly not in harmony with his environment. I agree with some of the other thoughts expressed here, that our brief existence as a species will preclude any hope of our discovering any intelligent extraterrestrial life. There is always the possibility that we will be discovered by an advanced extraterrestrial life form.
     
  5. BrianW

    BrianW Cinematographer

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    Those numbers are indeed huge and mind boggling. But this isn't exactly incomprehensible, or even incalculable.


    We know the percentage of stars that are like our sun, and we can calculate the percentage of those stars that have planets exactly like Earth orbiting them the ideal distance away. And this assumes that life requires a planet exactly like Earth orbiting a star exactly like our sun to arise.


    While we don't know the exact conditions that gave rise to life on Earth, we can make a pretty good stab at calculating the combinations of variations that would occur with plate tectonics, tides, weather/climate, and other factors that likely contributed to the conditions on Earth that gave rise to life. And while you're absolutely right that that's no guarantee that life will arise even if a planet exactly like Earth exists, it at least gives us a reasonable estimate of the number of candidates.


    So though we can't guess the actual frequency, we can at least calculate the number of planets on which it's a possibility, and I think that's pretty good.

    It is doubtful that the creators of such robots would intentionally send them across intergalactic distances. The good news is that interstellar distances within a galaxy are too small to be affected by the expansion of the universe. Our Voyager probe could reach the nearest star (not that it's going that direction, but still) in 75,000 years. At that speed, it would take only 1.5 billion years for self-replicating exploration robots to span the galaxy. Given that intelligent life could have existed in the universe in the past five or six billion years, that's plenty of time for self-replicating exploration robots to span the galaxy if the earliest civilizations that could have arisen had sent them out.


    But you're right about intergalactic distances. Going the speed of our Voyager probe, it would take three trillion years for a robotic probe to cross the typical 200 million light year distance between galaxies. That's many times older than the universe itself. Expansion would indeed overtake the probes and leave them forever stranded in the intergalactic void.
     
  6. jimmyjet

    jimmyjet Producer

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    i didnt try to calculate, thanks for doing so


    at least someone from our galaxy, if early enough, could have spanned our galaxy


    but if we look how long our sun has been around, it still hasnt formed life yet that has made these robots - not that we are necessarily as intelligent as other life forms could be !!


    but i am not convinced that a society would even want to create these self-replicating robots ?


    i think the argument fails miserably if one is using it as a firm conviction that previous life did not exist because we dont have replicating robots - it does not take a carl sagan to realize that !!
     
  7. Sam Posten

    Sam Posten Moderator
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  8. dvdclon

    dvdclon Second Unit

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    Here's something I found interesting:


    From The Wall Street Journal 12/25/2015 by Eric Metaxas

    "The same year Time featured the now-famous headline, the astronomer Carl Sagan announced that there were two important criteria for a planet to support life: The right kind of star, and a planet the right distance from that star. Given the roughly octillion-1 followed by 27 zeros-planets in the universe, there should have been about septillion-1 followed by 24 zeros-planets capable of supporting life.

    "With such spectacular odds, the Search for Extraterrestrial Intelligence, a large, expensive collection of private and publicly funded projects launched in the 1960s, was sure to turn up something soon. Scientists listened with a vast radio telescopic network for signals that resembled coded intelligence and were not merely random. But as years passed, the silence from the rest of the universe was deafening. Congress defunded SETI in 1993, but the search continues with private funds. As of 2014, researches have discovered precisely bubkis-0 followed by nothing.

    "What happened? As our knowledge of the universe increased, it became clear that there were far more factors necessary for life than Sagan supposed. His two parameters grew to 10 and then 20 and then 50, and so the number of potentially life-supporting planets decreased accordingly. The number dropped to a few thousand planets and kept on plummeting.

    "Even SETI proponents acknowledged the problem. Peter Schenkel wrote in a 2006 piece for Skeptical Inquirer magazine: 'In light of new findings and insights, it seems appropriate to put excessive euphoria to rest . . . . We should quietly admit that the early estimates . . . may no longer be tenable.'

    "As factors continued to be discovered, the number of possible planets hit zero, and kept going. In other words, the odds turned against any planet in the universe supporting life, including this one. Probability said that even we shouldn't be here.

    "Today there are more than 200 known parameters necessary for a planet to support life-every single one of which must be perfectly met, or the whole thing falls apart. Without a massive planet like Jupiter nearby, whose gravity will draw away asteroids, a thousand times as many would hit Earth's surface. The odds against life in the universe are simply astonishing. . . .

    "Fred Hoyle, the astronomer who coined the term 'big bang,' said that his atheism was 'greatly shaken' at these developments."

    [​IMG]
     
  9. hotrodguy

    hotrodguy Stunt Coordinator

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    Cool, an article from the future, maybe there is other life out there after all...or a time traveler. :P
     
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  10. Sam Posten

    Sam Posten Moderator
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    We're treading very close on P&R here, but I wouldn't take one quote by Fred Hoyle out of context here. He was a sci fi author in addition to his scientific role and he stood opposed to a lot of popular theories and opinions.
    http://en.wikipedia.org/wiki/Fred_Hoyle

    He was a complex guy who wasn't afraid of speaking his mind. Sound bites can't convey that.
     
  11. RobertR

    RobertR Executive Producer

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    The Fermi Paradox article is fascinating.
     
  12. dvdclon

    dvdclon Second Unit

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    The future date was my mistake: I pasted everything but the date. Wishful thinking on my part, perhaps.
     
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  13. Josh Steinberg

    Josh Steinberg Executive Producer
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    I'd like to believe that there's something else out there somewhere, but who knows? I was always amused by this Calvin & Hobbes quote on the subject:


    intelligence.
     
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  14. jimmyjet

    jimmyjet Producer

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    oh my gosh,


    that is cute !!
     
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  15. jimmyjet

    jimmyjet Producer

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    well, this is specific information that backs up my statement about large numbers and the frequency that life turns up


    no matter how large a number seems to our human brain, it is always infinitesimal to some bigger number !!


    but i will also counter this with we dont know the half of anything - there is more than likely a humongous piece of the puzzle that we dont even have a clue about - maybe never will
     
  16. Reed Grele

    Reed Grele Screenwriter

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    The dinosaurs had it made for millions of years. But they never built space ships, or had any way of predicting that an asteroid the size of Mount Everest would end the world as they knew it. We've been here only a small fraction of that time, but we are the only species that we know of that has developed technology to be able to leave our planet, and visit others.


    I hope to live long enough to see science prove that life exists elsewhere in the universe. But intelligent life? Doubtful.


    Right now, all our "eggs" are in one basket. The only way the human race has any chance of surviving is to someday leave earth and colonize other planets in this, and other solar systems.


    If intelligent life is so rare in this universe, then we have the obligation to preserve it.
     
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  17. jimmyjet

    jimmyjet Producer

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    well, we have a few billion years before we cant live here any more


    i think a much bigger task is to make sure that we get to that point - not sure that looks too promising, as of yet


    but as far as leaving - i am not convinced we have much of a chance of doing so


    we would both have to get there, and be able to live long enough (millions of years) to adapt to the planet before our genetics might be to the point of being able to live on the planet without artificial support


    but we might be smart enough to be able to retrofit the planet itself


    it is at least within the imagination of being able to move the planet to a more desirable orbit, add mass to it if needed for gravity, do a star trek terraform of it, etc. those things dont counteract the laws of physics.


    in fact, if we found a way to move the earth, we could do so to match the increase in size of the sun, keeping us at just the right distance. (assuming we could deal with the other planets and their new effects on us)


    plus how close to the speed of light can we bring space propulsion in that time ? we dont really understand space and time. but supposedly when we travel at relativistic speeds, our measure of space and time are dramatically different.


    what we currently measure to be millions of light years away can be measured in very small numbers at relativistic speeds.


    i think space and time, in its ultimate essence, is way beyond us at this point. so just what we may discover eons in the future could radically change our ideas about what is and is not likely !!
     
  18. DaveF

    DaveF Moderator
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  19. DaveF

    DaveF Moderator
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  20. jimmyjet

    jimmyjet Producer

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    also, according to relativity, any time we are moving at a speed relative to our environment, we are traveling faster into the future than someone at rest in that environment


    so the star trek type of travel is not possible, according to all known physics


    if i recall, impulse speed is the speed of light


    traveling at the speed of light, i could go from a to b, and measure no distance traveled and no time elapsed. at relativistic speeds near the speed of light, i would measure small distances and times.


    but i would be moving thru the future on a one-way trip. so i could never get back to my present. and if i traveled very far at that speed, we could literally be talking any number of years into the future.


    so if we were traveling fast enough to go very far, we would also be traveling far into the future of the environment in which we came from


    so it seems that the only aliens that we could encounter today would be people traveling at high speeds, but that started their journey eons ago. this could occur if these aliens developed these skills much earlier in our timeline.
     

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