List of Special Relativity Paradoxes.

In summary, there are many paradoxes in Special Relativity, including the Ladder Paradox, Bug-Rivet Paradox, Cooling Paradox, Twin Paradox, Trouton-Noble Paradox, Ehrenfest Paradox, Detonator Paradox, Falling Rod Paradox, Bar/Ring Paradox, Feenburg's Twin Paradox, and Supplee's Paradox. Each of these paradoxes challenges our understanding of the fundamental principles of Special Relativity, such as length contraction, relativity of simultaneity, and the constancy of the speed of light. However, through careful analysis and application of these principles, these paradoxes can be resolved and help us further understand the complexities of Special Relativity.
  • #1
greswd
764
20
Here's a catalogue of paradoxes in Special Relativity, for convenience sake.

If I've missed out any, do notify me.


Ladder Paradox:
A ladder enters a barn. In the barn's frame the ladder is length contracted and fits nicely, but in the ladder's frame the barn is length contracted and it won't fit. If doors at both ends of the barn shut, what will happen.

Easily dealt with using the relativity of simultaneity. Both doors do not simultaneously shut in the ladder's frame.


Bug-Rivet Paradox:
Similar to the Ladder Paradox, with a bug hiding in a hole. A Length COntracted rivet can't squash the bug in the bug's frame, but it is the other way round for the rivet.

This paradox is tricky as there is no way out for the rivet.


Cooling Paradox:
If a metal rod is heated till it glows, both ends cannot cool at the same rate in all frames.


Twin Paradox:
The mother of all paradoxes.


Trouton-Noble Paradox:
If there is no net torque in one frame, will length contraction produce one in another frame?


Ehrenfest Paradox:
A rotating cylinder and Length Contraction implies a different value of pi.


Detonator Paradox:
A variant of the Bug-rivet paradox. A bomb is activated by completing the circuit. Will it explode if a wire is passed through both terminals? Again, length contraction causes confusion.


Falling Rod Paradox.
A length contracted rod falls into a grate, but otherwise in the rod's frame. Also solved with relativity of simultaneity, this time involving a physical bending of the rod.


Bar/Ring Paradox:
A variant of the falling rod paradox, with the grate replaced by a ring, and no acceleration involved.

The solution is that due to length contraction of the bar in the ring's frame, in the bar's frame it is not directly aligned with the ring.
 
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  • #3
greswd said:
Here's a catalogue of paradoxes in Special Relativity, for convenience sake.

If I've missed out any, do notify me.

Ladder Paradox
[..]
Bug-Rivet Paradox:
[..]
This paradox is tricky as there is no way out for the rivet.
Tricky? Recently explained here in detail (search the forum).
Cooling Paradox
[..]
Twin Paradox:
[..]
Trouton-Noble Paradox:
[..]
Ehrenfest Paradox:
A rotating cylinder and Length Contraction implies a different value of pi.
:rofl: (sorry, could not help it!) - search the forum for explanations that leave π intact. :smile:
Detonator Paradox:
A variant of the Bug-rivet paradox. A bomb is activated by completing the circuit. Will it explode if a wire is passed through both terminals? Again, length contraction causes confusion.
[..]
Falling Rod Paradox.
[..]
Bar/Ring Paradox:
One more:
http://en.wikipedia.org/wiki/Bell's_spaceship_paradox
 
  • #4
Another one: An experiment for an entangled electron-positron pair as intrepreted from two different inertial frames moving at relativistic speed with respect to each other.
 
  • #5
bobc2 said:
Another one: An experiment for an entangled electron-positron pair as intrepreted from two different inertial frames moving at relativistic speed with respect to each other.

whats the name of that?
 
  • #6
greswd said:
Ladder Paradox:

Also commonly known as the "barn and pole" paradox, with a pole-vaulter carrying a pole, instead of a ladder.
 
  • #7
i didnt include bell's spaceship paradox because this involves acceleration.
 
  • #8
greswd said:
i didnt include bell's spaceship paradox because this involves acceleration.
So what? So do the twin paradox and the Ehrenfast paradox. SR handles acceleration fine. :smile:
 
  • #9
Feenburg's Twin Paradox is another good one.
 
  • #10
Ehrenfest Paradox is one I wasn't familiar with, fascinating!
 
  • #11
harrylin said:
greswd said:
i didnt include bell's spaceship paradox because this involves acceleration.
So what? So do the twin paradox and the Ehrenfast paradox. SR handles acceleration fine. :smile:
This.
 
  • #12
FeynmanIsCool said:
Ehrenfest Paradox is one I wasn't familiar with, fascinating!
It's a good one. It really confused me when I first encountered it. The key to understanding it is to realize that it's impossible to bring a disc to rotation without forcefully stretching the material.
 

1. What is special relativity and why is it important?

Special relativity is a theory proposed by Albert Einstein in 1905 that describes the relationship between space and time. It is important because it revolutionized our understanding of the physical world and has been confirmed by numerous experiments and observations.

2. What are some examples of paradoxes in special relativity?

Some examples of paradoxes in special relativity include the twin paradox, the ladder paradox, and the pole-and-barn paradox. These thought experiments highlight the counterintuitive consequences of the theory, such as time dilation and length contraction.

3. How do these paradoxes challenge our understanding of the universe?

The paradoxes in special relativity challenge our understanding of the universe by demonstrating that our everyday concepts of space and time may not be as straightforward as we think. They also force us to question our assumptions about the nature of reality and the behavior of objects at high speeds.

4. Are these paradoxes solvable or are they just theoretical conundrums?

While some paradoxes in special relativity may seem unsolvable or contradictory, they can all be resolved through careful analysis and application of the theory. However, some may still be considered theoretical conundrums as our understanding of the universe and technology may not yet be advanced enough to fully explain them.

5. What implications do these paradoxes have for our daily lives?

The paradoxes in special relativity may not have direct implications for our daily lives, as they typically occur at very high speeds or in extreme situations. However, the theory itself has led to advancements in technology, such as GPS systems, and has greatly influenced our understanding of the universe and the laws of physics.

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