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Laws of the universe

  1. May 17, 2009 #1
    hello,I read on this recently and a questions is running in my head , here it is: the laws of the universe all seem to be made so the universe can host life, change just one or a few(lets say more antimatter than matter) and the universe would be without life and observers, this leads me to an other question, the odds that our universe be made for life are slim, could if be that there are other universes that did not have the slim chance we got and those are forever silent? this would maybe imply that universes are made of random events and also pop up (if you allow me the expression)at random, and we are just the lucky ones. take note that I am not an expert on the dynamics of the universe, what are your opinions on this ?
     
  2. jcsd
  3. May 18, 2009 #2
    If the laws of nature precluded life, we wouldn't be discussing the topic.This biases conclusions we might make about the likelyhood of the physical laws supporting life--or so the anthropomorphic argument goes.
     
  4. May 18, 2009 #3

    Chronos

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    This is an inevitable conclusion. A universe with laws that prohibit life would forbid our existence. I consider this self evident. It proves nothing aside from the fact the universe must permit at least one planet with observers such as ourselves. It also implies other planets populated by intelligent creatures are highly probable.
     
    Last edited: May 18, 2009
  5. May 18, 2009 #4

    Chalnoth

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    It's difficult, I think, to word this properly. But the simple fact is that if the universe were not so that life is possible, then there would be nobody around to observe that universe. Since intelligent beings can only observe a universe which is conducive to life, said intelligent beings (i.e. us) can not conclude anything at all about the mere fact that the universe they find themselves in harbors life.
     
  6. May 18, 2009 #5
    I think I get what you mean, we cant conclude anything from the fact that the cosmos seems made for life, us being here does not bring a new information there could be a million other universes that are silent we would never be able to proove ther existence.
     
  7. May 18, 2009 #6

    DaveC426913

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    No. This logic is flawed.


    A dream house that's been won in a lottery will contain at least one lottery winner (else the lottery was not won). By your logic the dream house being populated by other lottery-winners is highly probable.
     
    Last edited: May 18, 2009
  8. May 18, 2009 #7
    What you described is often known as the "Anthropic Principle"
     
  9. May 18, 2009 #8
    your right on this but its kinda illogic that we are alone in the universe, you just need to look at the number of stars.. and other facts that can be taken into account.it would in my oppinion, be logic if there were other life somewhere in the universe. Or maybe im rong.
     
  10. May 18, 2009 #9

    DaveC426913

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    Opinions cannot be wrong, they can only be well- or poorly-supported.
     
  11. May 19, 2009 #10

    Chronos

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    That is an odd analogy. I merely assert that if you know with certainty one lottery winner exists, it is highly probable at least one other lottery winner exists somewhere in the universe. The principle of mediocrity [see http://en.wikipedia.org/wiki/Mediocrity_principle] [Broken] suggest it is improbable that anything about our planet is unique in the universe. And even the most pessimistic assessment of the Drake equation [see http://www.setileague.org/general/drake.htm] [Broken] inputs suggests a significant probability we are not the only sentient beings in our own galaxy. Projects like SETI [see http://www.seti.org/Page.aspx?pid=1241] suggest others share this opinion.
     
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  12. May 19, 2009 #11

    Chalnoth

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    Well, the mediocrity principle really isn't on any sort of strong foundation, though. It does seem that every time we think there is something unique about us or our planet, more knowledge proves us wrong. But I'm not so sure we can say it's definitely the case.

    That said, everything we are learning about life seems to indicate that there are likely to be at least a few planets in your typical galaxy that harbor life. And if there are just a few per galaxy, with well over 100,000,000,000 galaxies in the visible universe, well, that's a heck of a lot of life out there.
     
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  13. May 19, 2009 #12
    We take life originating on other planets as a chance, but why? Is it not possible that they just naturally evolve in certain ideal places. The chance that planets form is high, all you need is gravity. The chance that life evolves elsewhere should also be high ~ life is not exempt from the laws of physics. If physics created life on this planet then it should create life on other planets also.
     
  14. May 19, 2009 #13

    D H

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    The typical lottery winner is pretty danged mediocre. They just got lucky.

    That said, their is a lot to be said for the motion that the Earth is extraordinary. It's the right size and in the right place, it has a big honking Moon, it orbits a star that does not have a binary pair, is relatively stable, is neither too big nor too small, is neither too far from nor too close to the galactic center. Then there's Jupiter, which (1) exists, helping to clear out the junk from the solar system, and (2) didn't go on a kamikazee sunward dive.

    Simple life happened to develop on Earth (quickly, so based on a sample size of one, that's not so extraordinary), then complex life happened to develop on Earth (rather late, so so based on a sample size of one, that might be extraordinary). While semi-intelligent life has arisen multiple times, intelligent life in an environment conducive to advancement (how would hyper-intelligent squid develop fire, extract metals, build radios, get out into space?) and equipped with manipulators conducive to advancement has arisen once (based on a sample size of one). In the 4.5 billion years that it took for that one species to develop, the universe has not conspired to wipe out life (it's tried, multiple times), life hasn't committed suicide (it's tried, multiple times), conspired to wipe out that one intelligent species (it's tried, multiple times), and that one intelligent species hasn't committed suicide (yet). Life has gone ballistic a couple of times, leaving us with all those neat hydrocarbons without which a hyper-intelligent version of us would still be playing around with fire.

    In short, the Mediocrity Principle may well be yet another pile of hogwash brought to us by the humanities. The Earth might be anything but mediocre. Intelligent life might well be extremely rare.

    The Drake equation can be wielded to give answers ranging from "we are utterly alone" to "the universe is utterly crowded": It's pretty much worthless. Until we get beyond the basic problem of extrapolating from a sample size of one, the best answer is we don't know -- yet. The Kepler mission is a first small step toward getting past this problem.
     
  15. May 19, 2009 #14

    DaveC426913

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    In the analogy, the house is the universe. A lottery winner (civilisation) being in the dream house (in the universe) simply does not mean there's more than one lottery winner (civilization) in that house (universe).


    Oh, I see. OK.

    In a universe that's billions of light years wide, there's a lot of chances for any given set of similar circumstances to come together. So, whatever circumstances lead to development of life (even if there's ten thousand independent factors), it's still quite likely that those identical factors occur together in multiple places. Which means the ingredients for life are out there, in an uncountable number of locations, perfectly primed for life to develop.

    In a nutshell: in a universe large enough, if something happens once, it has a high probability of happening many times.

    I concede your point.
     
  16. May 20, 2009 #15

    Chronos

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    I havent given up on the possibility of life elsewhere within our own solar system, either current or in the past. Mars is a prime suspect, given fairly compelling evidence it once had an atmosphere and surface water. The possibility of liquid water still existing beneath its surface is tantalizing. I agree that sentient life is an exquisitely improbable result of evolution. But, in a galaxy as vast as ours, with hundreds of billions of stars, the highly improbably becomes highly likely. I see no flaw with the Drake equation. The premises are sound, if simplistic. Most of the variables cannot be handicapped at present, but, those that can have very good odds [sun-like stars accompanied by earth-like planets]. On the other hand, all species are relatively short lived on earth, and the same is most likely true everwhere else in our galaxy. I agree beings such as ourselves are exceedingly rare, and we may be the most advanced civilization currently residing in this galaxy. The Fermi paradox http://en.wikipedia.org/wiki/Fermi_paradox] [Broken] remains viable. The Kepler mission should be very interesting.
     
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  17. May 20, 2009 #16
    if mars had water on it liquid, it would be either to salty or to acid, wich lets me think that mars has never and will never host life)8. but about the other stars and exoplanets, well its nearly an evidence, given their number that some of them host life as we know it, or as we dont know it .we may not be the most advanced ones around, the wow signal suggest othewise. see http://en.wikipedia.org/wiki/Wow!_signal
    and for the chances of life existing somewhere else in the universe via the size of that universe well, what if the universe is infinite this changes the equation.
    also the best candidate for life in this solar system is the moon Europa, beneath its crust of soiled ice near some volcano down below.
    for full details view
    http://people.msoe.edu/tritt/sf/europa.life.html [Broken]
     
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