Idea for a perpetual motion machine

  • #1
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?
 

Answers and Replies

  • #2
1,948
200
This is a legitimate question. But you should be careful with your words. Perpetual machine questions are banned from these fora.
 
  • #3
jtbell
Mentor
15,643
3,689
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.
 
  • #4
What if you had the exterior rotating with a stationary generator in the core?
 
  • #5
Drakkith
Staff Emeritus
Science Advisor
20,991
4,810
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.
 
  • #6
907
88
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.
 
  • #7
berkeman
Mentor
58,204
8,258

Related Threads on Idea for a perpetual motion machine

  • Last Post
Replies
8
Views
3K
  • Last Post
Replies
1
Views
821
Replies
1
Views
316
Replies
35
Views
2K
Replies
62
Views
18K
Replies
4
Views
4K
Replies
2
Views
2K
Replies
9
Views
1K
Replies
13
Views
3K
Top