Speed of Light: Can We Go Faster?

[N468989]

is it possible to make light travel faster than the actual speed of light? an unrealistic idea is to "throw" the source of light in the direction of the emitting beam...theoretically it must work.

another question does anything travel faster than light?

 

[Doc Al]

is it possible to make light travel faster than the actual speed of light? an unrealistic idea is to "throw" the source of light in the direction of the emitting beam...theoretically it must work.

Not according to currently accepted physical theory (special relativity). The speed of light is the same with respect to any frame, regardless of the speed of the source.

another question does anything travel faster than light?

No.

 

[neutrino]

another question does anything travel faster than light?

http://www.math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/FTL.html

 

[Doc Al]

Good link. But no "thing" (object or particle) travels faster than light.

 

[neutrino]

But no "thing" (object or particle) travels faster than light.

In vacuum.

 

[Doc Al]

In vacuum.

D'oh! You got me! :tongue2:

 

[Jilvin]

I heard somewhere that you could lower the amount of energy in a vacuum and the speed of light itself could potentially raise by a fraction.

Not all vacuums are the same. The measure speed of light is currently only observed in one vacuum.

It wouldn't change much though...

 

[ZapperZ]

I heard somewhere that you could lower the amount of energy in a vacuum and the speed of light itself could potentially raise by a fraction.

Not all vacuums are the same. The measure speed of light is currently only observed in one vacuum..

Would you like to make an exact citation on where you "heard" this from? Keep in mind of the speculative post no-no that is explicitly stated in the PF guidelines.

Zz.

 

[rbj]

i just get tired of seeing this recur so often without people wondering if any such change in c can even be meaningful. as if we would know the difference.

quoting John Barrow:

[An] important lesson we learn from the way that pure numbers like $\alpha$ define the world is what it really means for worlds to be different. The pure number we call the fine structure constant and denote by $\alpha$ is a combination of the electron charge, e, the speed of light, c, and Planck's constant, h. At first we might be tempted to think that a world in which the speed of light was slower would be a different world. But this would be a mistake. If c, h, and e were all changed so that the values they have in metric (or any other) units were different when we looked them up in our tables of physical constants, but the value of $\alpha$ remained the same, this new world would be ''observationally indistinguishable'' from our world. The only thing that counts in the definition of worlds are the values of the dimensionless constants of Nature. If all masses were doubled in value [including the Planck mass m_P ] you cannot tell because all the pure numbers defined by the ratios of any pair of masses are unchanged.

i just wish people would ask: "how would we ever know that the speed of light has changed? ... changed relative to what??"

 

[neutrino]

i just get tired of seeing this recur so often without people wondering if any such change in c can even be meaningful. as if we would know the difference.

i just wish people would ask: "how would we ever know that the speed of light has changed? ... changed relative to what??"

Someone actually posted a question on similar lines, recently...
https://www.physicsforums.com/showpost.php?p=1421517&postcount=5

 

[rbj]

Someone actually posted a question on similar lines, recently...
https://www.physicsforums.com/showpost.php?p=1421517&postcount=5

thanks, i just jumped into the fray.

 

[Loren Booda]

The accelerating cosmos infers that beyond the universal event horizon, unobservable spacetime moves faster than light speed relative to us.

See also the (speculative) book Faster Than Light: Superluminal Loopholes in Physics (Plume) by Nick Herbert.