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Thread: Earth question

  1. #1
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    Post Earth question

    Hey guys, how are we all doing? been a very long time since i posted on here, i was just thinking the other day about how the moon was formed from smashing into the earth and taking some of the earth with it... my question is.. if the moon didn't smash into the earth and the earth stayed the size it was, do you think we would still have life as we know it? or would it be different.. feel free to correct or adjust my question if it does not make sense. thank you

  2. #2
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    There's an argument that the moon "stabilizes" the Earth's rotation axis. (In fact, what it does is provide a strong force making the Earth's axis precess relatively rapidly in the ecliptic plane, which makes it less sensitive to the longer-term perturbations caused by the gravity of other planets.) Because the Earth's axial tilt remains fairly tightly fixed around 23.5 degrees, there's a long-term stability of climatic zones, which means life has a chance to adapt to local conditions over long periods. Without the moon, the argument goes, the Earth would flip around between inclinations of 0-85 degrees, and there would be no stable climatic regimes, making conditions much more challenging for the evolution and persistence of life.
    But Lissauer et al. have shown that a moonless Earth would have geologically long periods of axial stability, punctuated by occasional shifts to new regimes. So conditions might be not much more challenging for life than our current situation, which after all is punctuated by dramatic climatic changes and extinction events. But with the added challenges to evolution, things would no doubt turn out a little (or a lot) differently.

    Grant Hutchison

  3. #3
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    Quote Originally Posted by elizabeth25 View Post
    Hey guys, how are we all doing? been a very long time since i posted on here, i was just thinking the other day about how the moon was formed from smashing into the earth and taking some of the earth with it... my question is.. if the moon didn't smash into the earth and the earth stayed the size it was, do you think we would still have life as we know it? or would it be different.. feel free to correct or adjust my question if it does not make sense. thank you
    The likely scenarios for the giant-impact hypothesis have a Mars-sized protoplanet impacting proto-Earth. The impactor didn't become the moon, most of it merged with Earth. The moon formed as a completely new body from the spray of debris.

    A pseudo-Earth that never experienced this event would be somewhat smaller, and would have a smaller iron core. It might have lost its magnetic field, or never formed one. It might have more atmosphere and water initially (much was likely lost in the Theia impact), but would lose more over time, especially if it lacked a magnetic field. It might look very much like a second Venus.

    If it took a more Earthlike path, pseudo-Earth would have weaker tides than Earth. Tidal pools are thought to have been important to the development of land organisms, and potentially to the formation of life. It would still have solar tides, but these would be weaker. They'd also be synchronous with the day/night cycle, which might have some important effects...you would only have bright sunlight at high tide. Moonlight has also been an important influence on evolution on Earth, and would be absent. The axial tilt would be somewhat more variable leading to more variation in seasons over time, recent numerical modeling estimated variation in the range of 20-25 degrees. It would probably also have less volcanism due to its smaller size and smaller core...note that volcanism is an important contributor to atmospheric gases and mineral nutrients available to the surface biosphere.

    So, it might be fairly Earthlike, or very much unlike Earth. Probably not as good for life overall, but not necessarily terrible.

  4. #4
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    I wonder if life would have started earlier without the cataclysmic event that formed the Moon? And if it did, would it have made any difference in the long run, getting that little bit of a head's start?

    On the flip side, there is a theory that a near-miss event shortly after the moon formed, contributed to life forming.

    A cataclysm may have jump-started life on Earth. A new scenario suggests that some 4.47 billion years ago—a mere 60 million years after Earth took shape and 40 million years after the moon formed—a moon-size object sideswiped Earth and exploded into an orbiting cloud of molten iron and other debris.
    I also have to wonder that even if the moon-forming event hadn't happened, would there have been other, similar events in the early chaotic period of the solar system.
    At night the stars put on a show for free (Carole King)

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  5. #5
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    Quote Originally Posted by Swift View Post
    I wonder if life would have started earlier without the cataclysmic event that formed the Moon? And if it did, would it have made any difference in the long run, getting that little bit of a head's start?

    On the flip side, there is a theory that a near-miss event shortly after the moon formed, contributed to life forming.



    I also have to wonder that even if the moon-forming event hadn't happened, would there have been other, similar events in the early chaotic period of the solar system.
    It’s quite difficult to re-run the experiment but it does seem that life needs some critical pinch points where it gets nearly exterminated but not quite. This kind of puts extreme pressure on the evolution principles and there seems to be a wild expansion of species after each near extinction event
    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.
    Originally Posted by Ken G

  6. #6
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    With the Moon closer, and tides on the early, hotter Earth greater, you had a lot of churning, mixing.
    There was a TED talk about Unilever soap models “evolved” on a computer when a true intelligent design attempt failed.

    The smokers on the sea floor—perhaps more of them— weren’t just natures alembics, perhaps they were difference engines as well...solving for life.

    Maybe recreate smoker designs online, with tides flowing past them? And see if you have any spin-ups. Whichever model works best is the target for Europa cryobot probe.

    I’ve often found vortices hypnotic, and the MN 1986 tornado had a double helix in its structure.
    There was a steam devil segment spotted once at the ABC coke plant in Tarrant Alabama...a smoker of another type.

    Biology takes you so far back. Blind chemistry only so far forward. I can’t prove it—but vortex action may be the cause of abiogenesis.

    For a planet with no moon—extant life forms may adapt to that, if not evolve there.

    Without a Moon helping to weather rock to dust, it might be a hard start.

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