Idea for a perpetual motion machine

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Discussion Overview

The discussion revolves around the concept of a rotating probe in interstellar space and whether it could maintain its rotation indefinitely. Participants explore the implications of drag from plasma and other forces on the probe's motion, while also addressing the classification of such a system in relation to perpetual motion machines (PMMs).

Discussion Character

  • Exploratory
  • Debate/contested

Main Points Raised

  • One participant questions if a probe brought to a full stop and then rotated would continue to rotate eternally, considering potential drag from plasma.
  • Another participant cautions about the terminology used, noting that discussions about perpetual motion machines are generally not permitted in the forum.
  • A participant clarifies that the concept discussed would not fit the typical definition of a PMM, as energy cannot be extracted without slowing the system down.
  • There is a suggestion about having an exterior rotating with a stationary generator in the core, raising questions about energy generation and system dynamics.
  • One participant reiterates that while energy extraction is not feasible, the system could potentially serve as a means of energy storage.
  • Concerns are raised about the existence of a truly closed system, with acknowledgment of external forces such as gravity and radiation affecting the probe.

Areas of Agreement / Disagreement

Participants express differing views on the classification of the discussed system in relation to PMMs, and there is no consensus on the feasibility of maintaining rotation indefinitely in the presence of external forces.

Contextual Notes

Participants note the limitations of the discussion, including the assumption of a closed system and the potential influence of external forces, which remain unresolved.

heterotictype1
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If someone were to send a probe out to interstellar space, bring it to a full stop and start rotating, would it continue rotating eternally? Or would drag from errant plasma slow it?
 
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This is a legitimate question. But you should be careful with your words. Perpetual machine questions are banned from these fora.
 
This would not be considered a "perpetual motion machine" in the sense that we mean in our rules, anyway, even if it did continue rotating eternally. A "perpetual motion machine" normally means a device that you can extract energy from, perpetually. There's no way to extract energy from this particular device without slowing it down.
 
What if you had the exterior rotating with a stationary generator in the core?
 
heterotictype1 said:
What if you had the exterior rotating with a stationary generator in the core?

The outside would slow down and the inside would begin to rotate until the two were rotating at the same speed and no more power would be generated.
 
jtbell said:
There's no way to extract energy from this particular device without slowing it down.
But it would be a way to store energy, though.

In reality I don't think there is any such thing as a 100% absolute closed system. In this example there would still be gravitational forces, radiation, and interaction with the interstellar medium, even if very small.
 

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