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    UFOs & Extraterrestrial Life

    starman
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    Post  starman on Tue Jan 14, 2020 10:55 am

    So K stars have advantages. A disadvantage, though, is the increased likelihood of tidal locking within the goldilocks zone. Taking that into account,  M stars may have virtually no habitable zone and that of Ks might be too small.


    Last edited by starman on Sat Jan 18, 2020 10:51 am; edited 1 time in total
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    Post  Tsavo Lion on Sat Jan 18, 2020 2:39 am

    The Navy Cryptically Says It Has Top-Secret UFO Briefings That Would Cause 'Exceptionally Grave Damage' to US National Security if Published
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    Post  starman on Sat Jan 18, 2020 11:41 am

    I never take government or "insider" reports at face value. While they serve the general purpose of familiarization, they also maintain key secrets through misinformation.
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    Post  Tsavo Lion on Mon Jan 20, 2020 7:13 am

    GJ 180 d has an orbital period of 106 days, and the team thinks this particular planet is far enough from its star Gliese 180 that it would not be tidally locked.
    https://www.sciencealert.com/wobbly-stars-have-revealed-two-new-goldilocks-zone-super-earths
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    Post  starman on Mon Jan 20, 2020 10:39 am

    I'm not very optimistic about either of them. Even if one or both aren't tidally locked, any life would probably evolve no farther than a thin film. I saw a hypothetical view of life on a world twice as massive as Earth, with a surface gravity treble what we experience. There were virtually no flying creatures and animals needed six legs instead of four... Imagine life on a world almost eight times as massive as ours...
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    Post  kvs on Mon Jan 20, 2020 6:10 pm

    The observations we have are skewed by the method used to detect these extra-solar planets. Earth sized planets are much
    harder to find compared to 2x Earth size and larger. So we have more of these large "Earth" observations. They do not mean
    anything. Since we have established that there is a rich spectrum of planetary systems, it would be unphysical if Earth sized
    and smaller were not available in large numbers. You never hear about 1/2 Earth size planets because the current method
    and instrument accuracy can't detect them. But they must exist.

    Back in the 1980s, it was not clear at all that so many Earth range planets were out there and the Star Trek universe looked
    contrived. Now, it is no longer an obscure issue. There is a vast number of Earth-sized (i.e. within 10% not 100%) planets
    out there. And they are basically guaranteed to have water unless they are pathological like Venus. Venus got screwed up
    by most likely a large impact that left its axis of rotation almost parallel to the orbital plane and left its rotation to be much
    weaker than that of Earth. If you look at Jupiter, Mars and Earth, they all have a 24-25 hour rotation rate. That is a characteristic
    feature of planetary formation for our star. Venus should have had a similar rotation rate and its axis of rotation should have
    been perpendicular to the orbital plane accounting for the wobbling that you normally find. Thus, "M class" planets really
    do exist in vast numbers. That leaves only life formation and development of intelligent life and civilizations as the uncertain
    variables. Unlike Star Trek, there is likely to be no endless availability of humanoid civilizations on these Earth-like worlds.
    Most of them probably do not have intelligent (as in civilization-forming) life.

    But given the enormous number of Earth-like planets, even if only a small probability of intelligent life exists on them, then
    that implies tens of thousands or higher order of such planets. Then we have the distribution of advanced civilizations and more
    primitive ones. The likelihood of Earth-type civilizations is not 100% and we probably are down to hundreds of actual instances.
    The number of sci-fi utopias among them is basically zero. All of the civilizations will be subject to the same physics and
    are guaranteed to have exploited carbon fossil fuels just like humans. All of these Earth-type planets will have fossil fuel
    resources since they are generic due to life and solar energy (oil, gas and coal are sources of fossilized sunshine). So it
    is highly probable that most advanced civilizations off themselves in the fashion humans are doing, i.e. via thermal death
    through CO2 pollution. Some of them may see the light earlier and transition to nuclear (including ultimately fusion), but
    these will number in the handful.

    So the reason we have no signals from aliens, is because the ones even capable of sending them are few and thus
    scattered over a vast volume and hence too far (1/r^2 attenuation of EM signal with distance). They are probably not
    building any enormous signal generators to attract our attention just like we are not building any such devices. And
    any advanced civilization will not waste energy in a fashion that would broadcast its existence to the whole universe.

    They are out there regardless of our ability to detect them. But their numbers are very small which is why we cannot
    detect them.
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    Post  Tsavo Lion on Mon Jan 20, 2020 9:01 pm

    So we have more of these large "Earth" observations. They do not mean anything.
    Super earths may have earth-size moons with right conditions for life.
    There may be a lot more advanced civilizations that been using different ways to communicate for 100s/Ks of years that we still can't detect. Also, they may scramble their radio signals to sound like natural radiation so only certain recipients can decode them.
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    Post  starman on Tue Jan 21, 2020 12:18 pm

    kvs wrote:Venus got screwed up
    by most likely a large impact that left its axis of rotation almost parallel to the orbital plane and left its rotation to be much
    weaker than that of Earth.

    Receiving almost twice as much insolation as Earth may have made a runaway greenhouse effect inevitable.


     Venus should have had a similar rotation rate and its axis of rotation should have
    been perpendicular to the orbital plane accounting for the wobbling that you normally find.

    At its distance from sol, tidal dissipation was another issue.

    So it
    is highly probable that most advanced civilizations off themselves in the fashion humans are doing, i.e. via thermal death
    through CO2 pollution.

    Smacks of temporocentrism. Mirroring the Cold War, Sagan thought many civilizations destroy themselves in nuclear wars.

    Some of them may see the light earlier and transition to nuclear (including ultimately fusion), but these will number in the handful.

    I don't doubt there will be grave crises due to global warming and other issues. But I've long opined the ultimate casualty will be democracy not civilization.  It's not that solutions are lacking it's just that people tend to resist them, as they involve sacrifices. Present government is obsolete and will go.

    So the reason we have no signals from aliens, is because the ones even capable of sending them are few and thus
    They are out there regardless of our ability to detect them.   But their numbers are very small which is why we cannot
    detect them.  

    The number of independently evolved civilizations is indeed small, I suggest only 100 or so in the whole galaxy. But many of these could've spread. We're mere beginners; others may have been spacefarers for millennia, maybe eons. I think ET has been here a long time.
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    Post  Tsavo Lion on Wed Jan 22, 2020 5:08 pm

    Bible astronauts
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    Post  GarryB on Thu Jan 23, 2020 6:56 am

    There were virtually no flying creatures and animals needed six legs instead of four... Imagine life on a world almost eight times as massive as ours...

    If you had ever seen a Penguin swim from an underwater perspective you would think it was flying... higher gravity means denser gases surrounding the planet and denser gases are easier to fly through...

    Imagine a creature that has an enormous sac like Portuguese man o' war jellyfish that produces light gases from the food it eats perhaps that can float around like a balloon in the thick atmosphere...
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    Post  starman on Thu Jan 23, 2020 11:27 am

    GarryB wrote:
    .. higher gravity means denser gases surrounding the planet and denser gases are easier to fly through...

    Na, a denser medium is harder to move through, more resistance.

    Imagine a creature that has an enormous sac like Portuguese man o' war jellyfish that produces light gases from the food it eats perhaps that can float around like a balloon in the thick atmosphere...

    What does it eat up there? To my knowledge there are no analogues in our atmosphere. Higher gravity isn't favorable to true flight because it takes more energy to become airborne and stay that way.

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