Can FTL Travel be Achieved With Mass of a Photon?

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Discussion Overview

The discussion centers around the plausibility of achieving faster-than-light (FTL) travel by manipulating the mass of an object, particularly in relation to the properties of photons. Participants explore theoretical implications, the nature of mass, and the constraints imposed by current scientific understanding.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant questions whether it is plausible to move faster than light in a vacuum by making the mass of something less than that of a photon.
  • Another participant challenges the idea of having mass less than zero, suggesting that a photon must have some form of mass due to its energy.
  • Some participants assert that a photon does not possess mass, with one stating that the concept of mass for a photon would violate gauge invariance in quantum electrodynamics (QED).
  • There are claims that energy does not imply mass, and that a particle cannot have mass and travel at the speed of light simultaneously due to relativistic effects.
  • One participant attempts to clarify Einstein's equation, emphasizing that a photon has zero rest energy and therefore zero mass, as it is never at rest.
  • Several participants express confusion regarding the implications of a photon’s mass on the original question about FTL travel.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the nature of mass in relation to photons, with some insisting that photons must have mass while others argue against it. The discussion remains unresolved regarding the feasibility of FTL travel.

Contextual Notes

Participants reference external discussions and FAQs regarding the mass of photons, indicating a lack of clarity and consensus on the topic. The conversation reflects ongoing debates in theoretical physics without definitive conclusions.

Lunct
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Really silly question, but if we assume that our current science is correct, is it plausible that we can move faster than light in a vacuum? Say, for example, can we make the mass of something less than a photon so it then can it move faster than light in a vacuum.

I know this sounds like a stupid question but I always here "at the moment we don't have the technology to move faster than light", but I have always believed it is simply not possible. Is it possible?
 
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Lunct said:
can we make the mass of something less than a photon

Less than zero?
 
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Vanadium 50 said:
Less than zero?
surely a photon has somewhat of a mass because energy does have mass
 
Lunct said:
so when a photon is moving is possesses mass
No.
 
Orodruin said:
No.
I can understand why it doesn't have a mass, it must have a mass. Maybe it is so small we can't possibly mesure it but it must have a mass. If it doesn't than why?
 
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Lunct said:
I can understand why it doesn't have a mass, it must have a mass
No. In fact, the photon having mass would directly violate gauge invariance of QED. Energy does not imply mass.
 
Lunct said:
I can understand why it doesn't have a mass, it must have a mass. Maybe it is so small we can't possibly mesure it but it must have a mass. If it doesn't than why?
Particle can't move with speed of light and also have some mass. That's just not possible due to relativistic effect.
 
  • #10
Lunct said:
I can understand why it doesn't have a mass, it must have a mass. Maybe it is so small we can't possibly mesure it but it must have a mass. If it doesn't than why?

In modern notation, Einstein's famous equation is actually ##E_0 = mc^2##. Note the subscript! ##E_0## is rest energy, which is the energy that something has when it's at rest. A photon is never at rest (always moves at the speed of light), so it has zero rest energy (and therefore zero mass). Its energy is entirely kinetic.
 
  • #11
okay a photon has no mas, can we get to the actual question now?
 
  • #12
Lunct said:
okay a photon has no mas, can we get to the actual question now?
It has been answered and the answer is no
 
  • #13
Lunct said:
Say, for example, can we make the mass of something less than a photon so it then can it move faster than light in a vacuum.

If photon has zero mass this doesn't make any sense.

Or in general, an object can't travel faster than the speed of light.
 
  • #14
Greg Bernhardt said:
It has been answered and the answer is no

And with that, this thread is closed.
 
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