Faster than the speed of light

DaleSpam

Sure, nothing is wrong with this. In this case v is the phase velocity of the wave, which is not limited to c and does not violate SR in any way as no matter, energy, or information is travelling faster than c.

What is being accelerated here? The phase velocity is not the velocity of any object and so it doesn't need any time to accelerate.

Cosmos2001

In an initial case, v is more the velocity of the “moving electrodynamic wave packet” that is being generated by the array of dipoles that is adjustable v=Lf (ref.: multiphase linear motors)

The array of dipoles is that which have mass and is to be accelerated. I was anticipating the overall energy requirement.

I think we can have two cases:

1. conventional “moving wave packet” propagating in the outer space having no matter, energy, or information travelling faster than c;
2. forced “moving electrodynamic wave packet” along the array length, receiving enough flow of energy for keeping (v>>c) , in this case, we can have strongly forced energy moving along the array length faster than c, but if the array of dipoles moves to the opposite direction, then the whole conjunct will have nothing faster than c.

Before the “moving wave packet” propagating away from the array of dipoles, will the extra energy be converted into acceleration propelling the array of dipoles to the opposite direction?

Obs: In this case, the array of dipoles is floating in the deep space. Another case is the array fixed inside a container in which net propagation of energy to dipoles would be blocked by stationary waves. I think if the array is floating in the deep space, without stationary waves surrounding it, it will have facilitated the propagation of energy to dipoles.

DaleSpam

I thought the dipoles were just generating the wave with phase velocity v>c. If the dipoles are being accelerated then what is doing the accelerating? Your setup is not very clear.

In any case, dipoles work according to Maxwell's equations so you will never get a group velocity >c or any material object travelling with v>c.

Phrak

It is defined in Infinitesimal Calculus.

.......The infinitesimal calculus does a better job of making sense of Δy/Δx where Δx --> 0, than any other calculus of which I am aware.

Phrak

"Nothing travels at greater than the speed of light" is just street language. Ignore it.

There's plenty of stuff that locally propagates at great then c. In fact most stuff does have this greater-than-c attribute in various incarnations. What's the point of this, Cosmos; what is driving you?

I get the impression that you are dissatisfied with conventional wisdom in the claim that massive stuff must propagate at less than c. In fact, I think you take this as a challenge. This I like. Am I in error in any of this?

Cosmos2001

I’m sorry; it is difficult to me to express it in a clearer form.
Now, I’m not trying to violate “nothing can move faster than light”; I’m trying to use it as support.

The energy in each dipole will never travel faster than c, but the overall energy moving along the array length will be forced (v>c), however, in the surrounding medium the speed is limited to c. To prevent speed violation; the array of dipoles will be forced to move to the opposite direction, doing (v=c), evicting energy flow faster than c.

If an object is traveling at low speed, vacuum doesn’t offer both support and resistance to change velocity. If the object is traveling close to c, it will offer resistance. The idea here is to take advantage of the resistance transforming it into support for initial acceleration of massive objects. Is it possible?

epenguin

I am surprised this thread reaches 4 pages without a mention of tachyons, particles with the remarkable properties: 1. Even I have heard of them 2. They can only travel faster than light - it takes infinite energy to slow them down to that speed. They achieve this remarkable property by their mass being an imaginary number.

Like all the most elite particles they are not actually known to exist. They seem to have been played with as an idea over the years. I suspect and would like to think this play is not entirely futile.

At the risk of being thought to have suffered an infantile regression, if they existed would we see them? Would they see us? Couldn't they exist in an incommunicado copresent parallel universe and mightn't they be worlds of positrons and antiprotons and this SOLVE THE PROBLEM OF BARYON NUMBER ASYMMETRY? Where do you get application forms for Nobel Prizes?

Anyway there is a Wikipedia article about them http://en.wikipedia.org/wiki/Tachyon - I found it quite difficult, but this one http://en.wikipedia.org/wiki/Tachyons_in_fiction was easier. It is based on the following fundamental principle: "it can impart a science-fictional "sound" even if the subject in question has no particular relation to superluminal travel (a form of technobabble, akin to positronic brain)."

DaleSpam

No, only the phase velocity will be >c. Energy does not move at the phase velocity.

I don't know how you arrive at this conclusion. The array of dipoles won't move at all, dipole radiation is symmetric.

Not even remotely. Lots of experiments have been done with phase velocities >c. The kind of propulsion you envision doesn't exist. There is no "traction" from phase velocities like you are supposing. In fact, there is no physical significance to phase velocities >c at all any more than there is a physical significance to the velocity of the "dot" from a laser pointer.

Cosmos2001

In a multiphasic linear motor, if (v<c), energy move at the phase velocity, it is hard to refute this; I think is a true fact for (v<c) because without this the linear motor would not work.
My hypothesis is, if (v>c), the energy will move forcedly at the phase velocity, facing relativistic resistance.

It is only a hypothesis.
Always seeing it as a multiphasic linear motor: if (v<c) then energy will flow along it in a non-forced way because it will not face relativistic resistance, energy will be dissipated into outgoing multiphasic waves increasing their amplitude. If (v>c) then energy will face relativistic resistance in order to be dissipated into the outgoing multiphasic waves, relativistic resistance will become a hypothetical relativistic support.

DaleSpam, I have no problem with you proving I’m wrong, if you can I’m grateful to you, but I felt I’m failing in describing my point of view.

Well, I know that “lots of experiments have been done with phase velocities >c”, but I’m not finding out one using an array of dipoles.
Please, could you give some clue to finding it?

DaleSpam

An array of dipoles is not a multiphase linear motor. A linear motor needs a primary and a secondary, not just one of the two. The energy moves from the primary to the secondary at the speed of light, not at the phase velocity.

No. If v>c then you will just have an ineffective transfer of energy from the primary to the secondary. Most of the energy will just be radiated away or dissipated as heat.

Just Google "phased array" and "phase velocity" to see what is there. I think you need to learn some basic EM concepts before worrying too much about the experimental details and relativistic effects. Specifically you should learn about motors and dipole antennas.

Cosmos2001

DaleSpam, frankly, you are impossible. I know an array of dipoles is not equal to a multiphase linear motor, but they are similar in some aspects. I know energy moves from the primary to the secondary at the speed of light, but the velocity of moving electric/magnetic fields can be adjustable (v=Lf).

I have failed completely in describing my point of view.
I’m giving up this topic.
You win!!!
Anyway, thank you for your suggestions; I will google them.

DaleSpam

The phase velocity of the fields is adjustable. No energy transfer occurs at the phase velocity.

You have successfully described your belief that by making a wave with a phase velocity >c you will encounter some sort of relativistic resistance which will give your dipole array some support. It is wrong, but you have successfully described it.

QuantumJG

My knowledge of relativity is pretty basic. The fact is that you cannot go faster than c or 299,792,458m/s.

A cool phenomena is Cherenkov radiation. It is similar to a sonic boom but with light. A body of mass cannot travel at c, but when light travels in a medium other than a vacuum, it will travel at <c. A particle can now potentially travel faster than that light and it will emit radiation as a result. A cool example is the blue glow in reactors.

MattRob

Actually, you can fairly simply travel faster than 299,792,458 m/s from your own perspective due to time dilation as you approach the speed of light. However, from a stationary perspective, you will never see anyone else go at that speed.

Okay, I don't understand something. So Photons don't have any mass? How do they exert force when they hit an object, then. Isn't that something mass does? It seems more like photons have some, just an incredibly tiny amount of mass.

Also, don't photons travel faster than c? Okay, a light wave travels at c, but because it travels in a wave, it isn't traveling in a straight line. So if it were to travel in a straight line, it would go above c. I think I've read about an experiment to do with this somewhere, where the scientists ultimately decided that it does travel faster than c but doesn't carry any information. This is something I've never really understood. How is it that something can travel faster than c but truly not carry any information?...

So, in my imaginary lab, I've got this device that can send out these straight-path photons that don't carry any information but travel faster than c. At the other end of the lab, there's a special computer I've made. The computer will start "recording" when it receives 5 photons in a string, each 1 nanosecond apart. After that, every nanosecond, if it doesn't receive a photon, it will make a 0. If it does receive a photon, it makes a 1. And so my other device is made to emit the photons at 1 nanosecond intervals so that the 1s and 0s end up creating the data. Viola, the fact that it exists at all is information. So if anything can travel faster than c, then it carries information.

Two other things, Quantum entanglement and quantum tunneling. I can sort of understand that entanglement doesn't carry information because it's randomized. But randomization is really a fancy way of saying we don't know the factors. So if they could be discovered, or the randomization somehow controlled, then couldn't entangled particles transfer information FTL?

And now Quantum tunneling. I haven't heard any reason why it wouldn't work as FTL.

DaleSpam

Usually "your own perspective" means "in a reference frame where you are at rest", in which case your velocity is 0 by definition.

No, that is something momentum does. Photons have momentum.

I think you need to learn a bit more about Maxwell's equations. A light wave is not some piece of matter which undulates like a snake to go forward. It is an electromagnetic field which varies from place to place.

Can you cite the experiment in question?

Cosmos2001

Photon can behave as either particle or wave.
It exerts a force when it hit an object, losing energy after that. Could it be because one of the wave half-cycle is mediating interaction between the interstellar medium and the object?

DaleSpam

I don't know what this means.