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  • Lunar tides in the Hadean

    From stargene@21:1/5 to All on Mon Jan 17 10:56:08 2022
    [[Mod. note -- I apologise for the long delay in posting this article,
    which the author submitted on 2022-Jan-11. The article was unfortunately mis-classified as spam by an over-eager filter.
    -- jt]]

    After the moon formed, due the proposed Theia off-angle
    collision with the new Earth, it was vastly closer to its
    parent planet; maybe 3 roche radii (?). Just how powerful
    and high would the resulting tides been on Earth? I include
    any oceans and tides within the solid (crustal?) Earth.
    Would such tides have contributed greatly to any plate
    tectonics and volcanism? Would this have contributed
    to the ultra-hot and highly fluid komatiite lavas?
    Thanks,
    Gene

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  • From Phillip Helbig (undress to reply@21:1/5 to stargene on Mon Jan 17 14:06:57 2022
    In article <[email protected]>,
    stargene <[email protected]> writes:

    After the moon formed, due the proposed Theia off-angle
    collision with the new Earth, it was vastly closer to its
    parent planet; maybe 3 roche radii (?). Just how powerful
    and high would the resulting tides been on Earth? I include
    any oceans and tides within the solid (crustal?) Earth.
    Would such tides have contributed greatly to any plate
    tectonics and volcanism? Would this have contributed
    to the ultra-hot and highly fluid komatiite lavas?

    Tidal force is inversely proportional to the cube of the distance, so
    they would be much higher. But was there water then? The solid Earth
    also has (much smaller) tides, and they would have been higher as well.
    The scaling isn't simple, though; in the case of solid-mass tides, the
    extreme viscosity plays a role, and also the shape of the coastline and
    so on also play a role, and its effect would not scale simply with the
    tidal force.

    See also https://astronomy.stackexchange.com/questions/39109/how-high-were-the-tides-back-when-the-moon-was-much-closer-to-earth

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