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Dokino21 t1_is1levy wrote

If our Moon was tidally locked to the Earth, from the beginning, how would the side not always facing the moon be impacted if at all?

Example: Moon in a position that doesn't impact wobble and tilt and is always facing the Eastern Hemisphere.

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(I'm writing a story and trying to give a scientific reason why life exists on this one continent and thought this could be a reasonable reason why life didn't develop to the same level anywhere else. I'm probably wrong)

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Brickleberried t1_is1ygag wrote

The Moon is tidally locked to the Earth, but the Earth is not tidally locked to the Moon.

I think if both were tidally locked to each other, such that one side of the Moon always faced one side of Earth, things would be less dynamic. You wouldn't have tides. Earth would be cooler because it wouldn't be flexing and squeezing and stretching from the Moon's shifting gravity (not sure if only a tiny bit or not).

I don't really know of a reason to make it so that it would be better for life on one side or the other of Earth.

The only related idea I can think of it that the Moon's far side has a thicker crust than the near side, which caused more lava flows on the near side. Maybe a similar thing could happen on Earth due to the Mars-sized object that hit the Earth to create the Moon where it knocks off a bunch of crust late in formation? It might not be scientifically possible, but sci-fi just needs to sound somewhat plausible.

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atomfullerene t1_is6zq58 wrote

>You wouldn't have tides.

You'd still have solar tides, which are about 1/3 of our current tides.

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atomfullerene t1_is6zv9o wrote

Well, you'd have month-long days. It wouldn't cause life to be on only one side of the planet though.

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Dokino21 t1_is7rmst wrote

Why would the moon only facing one side of the planet impact the length of days?

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atomfullerene t1_is7ttc8 wrote

The moon takes a month to go around the earth. If one side of the the earth faces the moon, it must therefore also take a month to rotate.

Granted, a "month" might be much shorter on some other planet if the moon was much closer. For example, pluto's moon charon faces only one side of the planet, but it only takes 6.4 days to orbit.

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Dokino21 t1_is81el3 wrote

I'm still confused. Why would the moon always facing the eastern hemisphere dictate the duration of the day? The moon would just be up there, staring at us, menacingly day and night. Wouldn't it?

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Rex_Mundi t1_isaw39q wrote

The presence of the Moon (which has about 1/81 the mass of Earth), is slowing Earth's rotation and extending the day by about 2 milliseconds every 100 years.

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atomfullerene t1_is82z96 wrote

Think about what it means for the moon to be visible in the sky...that side of the planet has to face the moon. Which means the planet has to take the same time to spin around once as the moon takes to travel around the planet once. Otherwise that side of the planet would get ahead of the moon or get left behind it.

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Dokino21 t1_is8ln59 wrote

I think I'm missing some vital piece of information in my brain because in my wee brain, I am talking moon is always above my head all the time, it does moon stuff, maybe it rotates like a good boy, but it's always there while the planet does it's rotation around the sun and does it's daily rotation. In my mind, the moon and earth are holding hands while the earth does it's 24 hours a day, 365 a year.

So I am really missing some kind of epiphany in understanding.

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