Exploring Phase Velocity and Time Travel Possibilities

In summary: Not every single posting with a question about relativity is designed to question its validity as some apparently seem to think.
  • #1
byron178
157
0
When something has a phase velocity greater than the speed of light,will it travel backwards in time in one frame?
 
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  • #2
Nope.
 
  • #3
ghwellsjr said:
Nope.

but relativity says that if something were to travel faster than light than in one frame it will travel backwards in time.
 
  • #4
ghwellsjr said:
Nope.
Hmm, how do you conclude that?
 
  • #5
byron178 said:
but relativity says that if something were to travel faster than light than in one frame it will travel backwards in time.
No, it doesn't. It says the normal matter cannot travel faster than light (in any frame).
 
  • #6
HallsofIvy said:
No, it doesn't. It says the normal matter cannot travel faster than light (in any frame).
I would agree with that but do you think that that would imply that the phase does not go backwards in time in another frame?
 
  • #7
Passionflower said:
I would agree with that but do you think that that would imply that the phase does not go backwards in time in another frame?

ive read that its like an illusion the phase velocity traveling faster than light.
 
  • #8
Passionflower said:
I would agree with that but do you think that that would imply that the phase does not go backwards in time in another frame?
Apparently then the problem is that you do not understand what "phase" velocity means. "Phase" velocity is a property of a wave. There is nothing with mass moving at the "phase" velocity of a wave.
 
  • #9
HallsofIvy said:
"Phase" velocity is a property of a wave. There is nothing with mass moving at the "phase" velocity of a wave.
Yes, and I implied that that was not the case?

Phase velocity can be observed, and thus it can also be observed in many frames of reference.
 
  • #10
The propagation of emf in a waveguide has a wave velocity greater than c.

What does "backwards in time" mean?
 
  • #11
Passionflower said:
Yes, and I implied that that was not the case?

Phase velocity can be observed, and thus it can also be observed in many frames of reference.

Plenty of things can be observed to be faster than speed of light. But they don't transmit information or matter.

Consider two very very long straight rulers, both moving at uniform speed (<c of course) perpendicular to their elongated direction. The point at which they cross has speed proportional to 1/tan(theta), where theta is the angle between them. So this point can travel at any arbitrarily high speed. Just like any point of the wave front of a dispersive wave.
 
  • #12
mathfeel said:
Plenty of things can be observed to be faster than speed of light. But they don't transmit information or matter.
Yes I am aware of that.

Did anyone claim the contrary?

Not every single posting with a question about relativity is designed to question its validity as some apparently seem to think.
 

FAQ: Exploring Phase Velocity and Time Travel Possibilities

1. What is phase velocity and how is it related to time travel?

Phase velocity is the speed at which a wave travels through a medium. It is not directly related to time travel, as time travel is a concept that is still largely theoretical and not fully understood by science.

2. Can phase velocity be faster than the speed of light?

No, according to the theory of relativity, the speed of light is the maximum speed at which any object can travel. Therefore, phase velocity cannot be faster than the speed of light.

3. Is it possible to travel back in time by manipulating phase velocity?

Currently, there is no scientific evidence or theory that suggests that manipulating phase velocity can lead to time travel. The concept of time travel is still a topic of ongoing research and exploration.

4. Are there any real-world applications of studying phase velocity and time travel?

Studying phase velocity and time travel can help scientists better understand the fundamental properties of the universe and potentially lead to advancements in fields such as astrophysics and quantum mechanics.

5. How do scientists measure phase velocity?

Phase velocity is typically measured using specialized equipment such as oscilloscopes and phase meters. These instruments can detect the changes in phase of a wave as it travels through a medium and calculate the velocity based on those changes.

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