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Thread: If there is an alien civilization at the same technological stage as us

  1. #1
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    If there is an alien civilization at the same technological stage as us

    What's the nearest distance from Earth where we would NOT be able to miss their existence? Would be 10 light years? 30 light years? Less than a light year?

  2. #2
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    There was a debate about detecting a nuclear explosion on a planet at Proxima 4+ LY away. In principle we could detect the photons if we happened to be looking but the light from the star would probably mask it. We can detect small radio transmission on the scale of our solar system, eg Voyager, but the signal to noise of a planet around any star is going to make it unlikely that we would detect our kind of civilisation unless by chance we see a nuclear war on a nearby system, in which case we might also get the spectrum of isotopes to confirm what the blip was.So for exoplanets mostly atthe mo., I think no hope.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
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  3. #3
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    Quote Originally Posted by profloater View Post
    There was a debate about detecting a nuclear explosion on a planet at Proxima 4+ LY away. In principle we could detect the photons if we happened to be looking but the light from the star would probably mask it. We can detect small radio transmission on the scale of our solar system, eg Voyager, but the signal to noise of a planet around any star is going to make it unlikely that we would detect our kind of civilisation unless by chance we see a nuclear war on a nearby system, in which case we might also get the spectrum of isotopes to confirm what the blip was.So for exoplanets mostly atthe mo., I think no hope.
    I thought radar could be detected at interstellar distance?

  4. #4
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    Radar pulse can be detected at greater distances but also mimic certain unusual natural sources.

  5. #5
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    So theoretically could there be an alien civilization at the same exact stage as us as near as 4 LY away and we can miss them?

  6. #6
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    Quote Originally Posted by Plat View Post
    So theoretically could there be an alien civilization at the same exact stage as us as near as 4 LY away and we can miss them?
    I think we would be detectable at that distance. We are twice as powerful as the sun at radio wavelengths apparently.

    Voyager transmits at 23 Watts from beyond the edge of the solar system and NASA can pick up the signal.

    More of a problem with ETs at the exact same technological stage as us, is the radius of the radio bubble. It's only around 100 light years, a triflingly small volume compared to the galaxy as a whole.

  7. #7
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    The universe looks to play tricks--pulsars that are first called LGMs..

    Leave it for some new degenerate stellar matter to perfectly replicate the first five minutes of an "I love Lucy" episode by accident, and cause more false hopes.

    "Look aliens are re-broadcasting TV back to us like from CONTACT--no...wait...it's another &#$@! star!"

  8. 2019-Feb-15, 08:42 PM

  9. #8
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    I think there is a question of whether we'll be in the right place at the right time to see intermittent events powerful enough to reach us.

    We're getting close to observing the entire sky simultaneously, but we're not there yet.

  10. #9
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    As I understand it, we are effectively invisible to any civilization like ours.

    Is Our Civilization Detectable? tells the story.

    COSTS AND DIFFICULTIES OF LARGE-SCALE ‘MESSAGING’, AND THE NEED FOR INTERNATIONAL DEBATE ON POTENTIAL RISKS is the paper.
    Where the telescope ends, the microscope begins. Which of the two has the greater view?

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