Does light speed apply to all waves traveling in vacuum?

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Discussion Overview

The discussion revolves around whether the speed of light applies to all waves traveling in a vacuum, particularly focusing on electromagnetic waves and other types of waves, such as gravitational waves and matter waves. Participants explore theoretical implications and the nature of wave propagation in different contexts.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants propose that while light is a specific type of electromagnetic wave, other waves might travel faster than the speed of light, depending on their frequency.
  • Others argue that all electromagnetic waves, regardless of their frequency, travel at the speed of light in a vacuum.
  • It is noted that all massless waves and particles are said to travel at the speed of light, but there is uncertainty regarding the behavior of matter waves associated with particles.
  • One participant questions whether gravitational waves have been experimentally proven to travel at the speed of light, suggesting that there may be limitations in the experimental evidence.
  • There is a discussion about the implications of relativistic velocity addition, particularly in scenarios where a light source is moving relative to an observer.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the speed of different types of waves in a vacuum, and the discussion remains unresolved with no consensus on the applicability of the speed of light to all waves.

Contextual Notes

Some claims are based on specific definitions of waves and their properties, and there are unresolved questions about the experimental validation of certain theories, particularly concerning gravitational waves.

Crazy Tosser
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Seriosly, waves have different frequencies, and light is somewhere in the middle of the EM spectrum, then maybe the right or left side could travel faster than c
 
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Light is generally the term used to refer to electromagnetc waves in the visual spectrum (but its really the same as other E&M waves, just at different energies).
They all behave generally the same, i.e. all E&M waves travel at the speed of light.
 
All massless waves (and all massless particles) travel at the speed of light.
 
That includes gravity, by the way.
I think that in one regard, you can say that not all waves travel at c in vacuum, but I'm not sure if my reasoning applies. It seems to me that the matter waves associated with a particle can't do so, since the particle itself can't.
 
CT, all EM waves travel at the same speed in a vacuum. As far as I am aware this is not the case when dealing with a medium in which the waves are traveling slower.

Phlogistonian said:
All massless waves (and all massless particles) travel at the speed of light.

If by speed of light you mean around [itex]3\times10^8[/itex] then I can't see how that is correct.
 
Crazy Tosser said:
Seriosly, waves have different frequencies, and light is somewhere in the middle of the EM spectrum, then maybe the right or left side could travel faster than c
The phase velocity of a wave is a product of the frequency and wavelength:

L*f=v

The electromagnetic wave equation has solutions with different frequences, but the wavelength must be inversely proportional to the frequency, so the product is always the same:

L*f=c
 
Danger said:
That includes gravity, by the way.
I think that in one regard, you can say that not all waves travel at c in vacuum, but I'm not sure if my reasoning applies. It seems to me that the matter waves associated with a particle can't do so, since the particle itself can't.


Has it been experimentally proven that gravity waves travel at the speed of light.
 
_Mayday_ said:
If by speed of light you mean around [itex]3\times10^8[/itex] then I can't see how that is correct.

The original question was about waves in a vacuum.
 
Phlogistonian said:
The original question was about waves in a vacuum.

That doesn't make what you said correct.
 
  • #10
_Mayday_ said:
That doesn't make what you said correct.

You can think what you want. I won't engage in a pointless argument over semantics.
 
  • #11
Well, how about traveling slower than the speed of light? If you are in a car that's goin at 100mph and you light a flashlight backwards, does the light travel at c-(100mph)?
 
  • #12
Crazy Tosser said:
Well, how about traveling slower than the speed of light? If you are in a car that's goin at 100mph and you light a flashlight backwards, does the light travel at c-(100mph)?

Please refer to the basics on relativistic velocity addition.

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/einvel.html

The speed of light is constant in all inertial frames, no matter the speed of the source.

Zz.
 
  • #13
bassplayer142 said:
Has it been experimentally proven that gravity waves travel at the speed of light.

only to within 20%, IIRC.
 
  • #14
Crazy Tosser said:
Well, how about traveling slower than the speed of light? If you are in a car that's goin at 100mph and you light a flashlight backwards, does the light travel at c-(100mph)?

Excellent question, CT, and the answer is very important (ZapperZ already mentioned it). Make sure to keep reading every text you can get your hands on, because we've all asked this question at one time or another; if you can accept the true answer it will blow your mind.
 

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