Lunar tides in the Hadean

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stargene

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Jan 17, 2022, 1:56:12 PMJan 17
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[[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

Phillip Helbig (undress to reply)

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Jan 17, 2022, 5:06:59 PMJan 17
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In article <1c6aeebc-7004-44e6...@googlegroups.com>,
stargene <star...@sbcglobal.net> 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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