• Kellenved@sh.itjust.works
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      1 day ago

      You’re not deep enough yet, tides and earths core only exist because stars exploded billions of years ago and some particles eventually formed earth

    • JackbyDev@programming.dev
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      20 hours ago

      This raises an interesting question in my mind, does tidal power make the earth get closer to the moon? Because if you got all the energy out of it, then the water wouldn’t move, so I guess it’s the same as gravitational potential in that sense, but I guess it’s removing it, so less gravitational potential means either less mass (not the case) or less distance.

      • excess0680@lemmy.world
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        16 hours ago

        The opposite happens. Tidal energy is what causes the moon to drift farther away from the earth, as the moon loses angular velocity.

        • gandalf_der_13te@feddit.org
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          10 hours ago

          actually, the moon gains angular momentum from the tidal movement that it causes, and that’s what makes it move further away. the reason is that it takes Earth about 1 day to rotate once around its axis, but it takes the moon 28 days to rotate once around Earth’s axis. so Earth has a higher angular velocity, and the tidal movement tries to reduce that difference to make the two tidally locked eventually. ironically, this process transfers angular momentum to the moon (to speed it up), which makes it move further away and thus the angular velocity actually decreases. yeah, orbital mechanics is weird.

          (btw this is not a joke. it’s really that way, difficult to comprehend i know).

          • excess0680@lemmy.world
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            12 hours ago

            If you mean harvesting tidal energy, the effect on the moon would be minimal. The loss of angular momentum the moon experiences is due to the mass of the earth’s waters. I could not imagine anything humans could build that could extract enough tidal energy that it would disrupt the moon without utterly destroying the environment at the same time (by way of nullifying tides somehow). In fact, to harness tidal energy, one way would be to use underwater turbines. They would have an immediate effect to the local environment but a negligible amount to the moon itself.

            • JackbyDev@programming.dev
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              12 hours ago

              I know its minimal, I’m not saying it’s a concern, I’m just saying if we are harvesting it, doesn’t that mean it’s pulling us closer to it? It’s not magically free energy (in the physics sense), so what else could it be other than converting the potential gravitational energy between the earth and moon into something else?

              • gandalf_der_13te@feddit.org
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                10 hours ago

                see my other reply in this thread

                basically it doesn’t move the moon closer, but it makes the Earth rotate slower. that’s where the energy comes from.

                basically the tides transfer angular momentum from the Earth to the moon.

    • Agent641@lemmy.world
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      1 day ago

      Geothermal comes from friction inside the core, residual heat from planet formation, and radioactive decay. Since all elements heavier than hydrogen were fused inside stars, and heavier actinides like uranium are formed in second gen stars, and the inertia of dust that coalesces into planetary bodies including the earth and the moon originated from dying stars going supernovae, geothermal and tidal energy are products of stellar explosions, either inertial, kinetic, or radioactive. Tides are driven by the moon, whose energy is kinetic, stored from past supernovae