How rare is life in our Universe?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Seattle, Jun 18, 2018.

  1. Seattle Valued Senior Member

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    Life could be anywhere so of course that includes large stars that become supernovas. Life would definitely be snuffed out in such a scenario (everywhere in its solar system and far beyond).

    Our Sun has an effective "main sequence" phase of approximately 10 billion years but life on Earth probably only has another 1 billion years (which is way before it goes into its Red Giant phase). This is because it burns about 10% hotter for every billion years and that is predicted to be more than life on Earth could stand.

    Regarding radio waves coming back around to Earth time after time...this doesn't happen. We may receive such waves if they just haven't yet had time to reach us but there is no "coming back around". The Universe is thought to be flat. Even if it's not, not enough time would exist for anything to ever come back around. For one thing the Universe is huge if not infinite and for another it's expanding faster than the signals are travelling.
     
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  3. gebobs Registered Member

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  5. RainbowSingularity Valued Senior Member

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    most advanced civilisations would go a long way out of their way to hide their existance.
    look at how close humans were to space exploration back in the late 50s
    slavery was considered normal in the usa then.
    imagine that on an intergalactic scale.
    genocide would be considered normal.
    it is an awfully good bit of luck the human species did not make the jump to inter staller travel back then because;
    it is arguebale that the species is capable now, of not spreading genocide & wiping out any other species it comes in contact with.

    if you could make remote control stealth fighter jets for free
    would you give them to bulcan & asian & african war lords to use ?
     
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  7. Gawdzilla Sama Valued Senior Member

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    Why would they have FTL and not have BLT?
     
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  8. Gawdzilla Sama Valued Senior Member

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    A really horrible band.
     
  9. Gawdzilla Sama Valued Senior Member

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    That is completely weird.
     
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  10. Michael 345 Bali in Nov closer Valued Senior Member

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    I was about to post if we tasted like chicken

    But bacon better

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  11. Dinosaur Rational Skeptic Valued Senior Member

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    The existence of life elsewhere seems likely. It occurred on Earth almost as soon as suitable conditions for its existence existed. Considering the number of galaxies, it is reasonable to believe that it exists elsewhere.

    I expect life to occur in many galaxies & expect some galaxies (perhaps our own) to have more than one planet with living creatures.
    The existence of technological cultures is a different issue: I expect them to be rare.

    I avoid discussing intelligence elsewhere. Among local friends such discussions get bogged done with definitions of intelligence. I have friends who consider the octopus to be intelligent & various mammals (EG: Other primates) to be intelligent.

    BTW: It is difficult to deny that other primates are intelligent.​

    I prefer to discuss technological cultures,
    which avoids definition problems.

    I expect technological cultures to be rare: With many galaxies having none & few having more than one.
    Dinosaurs existed for millions of years. The last of them were not much (if any) closer than the first ones to developing technology. Similarly for other types of living creatures.

    The primate body design seems best suited to developing technology. Only Homo Sapiens actually did.

    Note that the Denisovans & Neandertals seemed to have the potential but became extinct at a Stone Age level of culture.

    Evolution does not seem to inevitably result in a technological culture.







     
  12. Xelor Registered Senior Member

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    148
    I figured that'd be possible. What I don't know is how probable/rare it is, but I suspect it could be common enough that life has been started and snuffed out enough times to affect the ability of one's discerning whether exist (or existed recently enough for one to detect) other "advanced" life forms. I suppose one might encapsulate the notion as "timing is everything."

    I think I recall hearing that near-Earth supernovas means one that happens anywhere from 50 to 1000 light years away. If one happened to any star that far away, well, in astronomical time spans, any such life would have been long gone before we were even able to receive their signals. On the other hand, it seems as though it'd take an awful lot of luck for the most distant stars we've discovered to be, here at the juncture of our finding them, at the point whereby our discovery of them coincides fairly closely with there being life on them that's "chatty" and that we are thus due to somewhat soon start hearing from them. (Nevermind that if we do soon hear from them, relative to their own frame of reference, they're civilization(s) are long gone, but I suppose it'd be nice to learn that they were once there.)


    That's what I thought too.
     
  13. gebobs Registered Member

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    As Jerry said, the Dead are like black licorice. Not everyone likes black licorice. But people who do really like black licorice.

    Regardless, it was a play on "What would make the trip worthwhile."
     
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  14. gebobs Registered Member

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    The 1850s or 1950s?
     
  15. Michael 345 Bali in Nov closer Valued Senior Member

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    Wasn't that because we screwed them out of existence?

    Great thought bubble

    Now MAKE LOVE NOT WAR starts to make sense

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  16. kx000 Valued Senior Member

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    Life may be rare, but space is infinite. Keep going far enough out there and you will find yourself.
     
  17. Seattle Valued Senior Member

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    Do you have any evidence that space is infinite? If it is, that doesn't imply that you will find yourself.
     
  18. gmilam Valued Senior Member

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    Q: Why do Grateful Dead fans wave their hands in front of their face?
    A: To keep the music from getting in their eyes.

    Q: What did the Grateful Dead fans say when they ran out of drugs?
    A: Man, these guys suck.

    (Maybe these should go in the Hallucinogenic Drugs thread.)
     
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  19. sideshowbob Sorry, wrong number. Valued Senior Member

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    If you go somewhere to find yourself you're wasting your energy.
     
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  20. Michael 345 Bali in Nov closer Valued Senior Member

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    Quicker to look in the mirror

    Oh there you are

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

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    I'm hoping to see evidence of life on Mars or Europa or somewhere within my lifetime.
     
  22. Seattle Valued Senior Member

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    That would be nice for sure.
     
  23. kx000 Valued Senior Member

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    Technically infinity is a negative trait and is not part of nature.
    But you would. If you think about it there are only so many shapes and colors so inevitably I would reoccur forever.
     

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