Unlocking Limitless Green Energy: Harnessing Earth's Rotational Kinetic Energy

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Discussion Overview

The discussion revolves around the concept of harnessing the Earth's rotational kinetic energy for energy production. Participants explore theoretical and practical implications, including potential mechanisms, engineering challenges, and ecological considerations. The conversation touches on various aspects of physics and engineering, including angular momentum and tidal energy.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose the idea of using gyroscopic mechanisms to tap into the Earth's rotational energy.
  • Others express skepticism about the feasibility, noting that extracting energy would require slowing the Earth's rotation, which involves transferring angular momentum.
  • A participant mentions the difficulty of engineering a system that remains stationary relative to the Earth's rotation to effectively harness this energy.
  • Concerns are raised about the ecological impact of changing the Earth's rotation period, with some suggesting that significant changes could threaten species survival.
  • There is a discussion about conservation of angular momentum, with one participant asserting that without the moon's involvement, energy extraction would be impossible.
  • Another participant questions the idea that driving a car could affect the Earth's angular momentum, leading to further clarification that such effects would be temporary.
  • Some participants highlight tidal energy as a practical method of tapping into the Earth's rotational kinetic energy, noting existing engineering approaches.

Areas of Agreement / Disagreement

Participants express a range of views, with no consensus on the feasibility of harnessing the Earth's rotational energy directly. While some support the idea of using tidal energy, others argue against the practicality of extracting energy without affecting the Earth's angular momentum.

Contextual Notes

Participants acknowledge limitations in their understanding of the implications of changing the Earth's rotation and the technical challenges involved in creating a viable energy extraction system.

GRDixon
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The Earth rotates in inertial space. The amount of rotational kinetic energy is enormous ... millions of mankind's annual consumption. Is there any kind of apparatus, perhaps one based on gyros, that could tap into this energy?
 
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I don't this can work at all. To use the kinetic energy of the Earth we must slow it down, and that can only be done by transferring the angular momentum of the Earth to something else (the moon for tidal energy).
 
Gyros? Well, the energy required to sustain their action exceeds the energy able to be extracted from this or any other arrangement.
 
From an engineering perspective, I think it would be rather difficult to get the other portion of the contraption to stand still (i.e. you have to have something that's not rotating with the Earth to take advantage of the Earth's rotation). Good luck with that!

Addendum:

I hadn't considered Foucault. Neat idea.
 
Anyway, if you change the period of rotation of the Earth, many species wouldn't adapt and die.
 
fluidistic said:
Anyway, if you change the period of rotation of the Earth, many species wouldn't adapt and die.

Well, I wouldn't deny that's true for a significant change in the period. But at what point do we consider it significant?
 
Pythagorean said:
I hadn't considered Foucault. Neat idea.
What about conservation of angular momentum?

Try tidal power.
 
  • #10
cesiumfrog said:
What about conservation of angular momentum?

Try tidal power.

Another good one! This one is already being used too! There's several different engineering approaches to it.
 
  • #11
fluidistic said:
Anyway, if you change the period of rotation of the Earth, many species wouldn't adapt and die.
Don't imagine that there would be any significant change in the period of rotation if you consider the mass of the Earth.
It might actualy be speeding up at present due to the amount of hydro electric scheems in the northern hemisphere.
I imagine any slowing would be counteracted by rainfall, by angular momentum when it falls or dams.
 
  • #12
...anyone going to attempt to quantify the issue...?
 
  • #13
russ_watters said:
...anyone going to attempt to quantify the issue...?

If you do not use the moon in some way, the energy you can gain is exactly zero, since there's no way to reduce the angular momentum of the earth.
 
  • #14
there's no way to reduce the angular momentum of the earth.

How's that? doesn't driving a car give angular acceleration the the earth?
 
  • #15
Zula110100100 said:
How's that? doesn't driving a car give angular acceleration the the earth?

And it takes it away again as soon as you stand still again. The angular momentum of the Earth with the car remains the same.
 
  • #16
willem2 said:
If you do not use the moon in some way, the energy you can gain is exactly zero, since there's no way to reduce the angular momentum of the earth.

As the Earth rotates, the tidal bulge follows a bit behind the Earth-Sun line (neglecting the moon) and so there is a tidal torque on the Earth reducing its rotational angular momentum and converting some of that to orbital angular momentum. You can alter the angular momentum of the Earth but not of the Earth-Sun or Earth-Sun-Moon system except by exterior effects (e.g. Jupiter).

As mentioned tapping tidal energy is tapping the rotational kinetic energy of the Earth. Tapping tidal energy would imperceptibly but quantifiably increase the lag of the tidal bulge, increasing the rate of tidal slowing of the Earth's rotation.
 

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