Faster than the speed of light

[Dale]

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.

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.

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.

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.

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?

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]

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.

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.

 

[Dale]

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).

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

I have failed completely in describing my point of view.

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]

Is it possible to go faster than the speed of light? And why do some scientists say you can't?
Thanks -_-!

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.

 

[Dale]

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.

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

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?

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

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 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.

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?...

Can you cite the experiment in question?

 

[Cosmos2001]

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

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?

 

[Dale]

Could it be because one of the wave half-cycle is mediating interaction between the interstellar medium and the object?

I don't know what this means.

 

[DaveC426913]

I don't know what this means.

Cosmos plays pretty fast and loose with terms.

 

[Cosmos2001]

Cosmos plays pretty fast and loose with terms.

Photon doesn’t have any mass, but it has momentum.
Momentum is the product of the mass and velocity (p=mv)
It seems contradictory.
Is there an explanation for this, such as an interaction with something else?

 

[DaveC426913]

Photon doesn’t have any mass, but it has momentum.
Momentum is the product of the mass and velocity (p=mv)

That is the classical definition of momentum.

 

[Dale]

Photon doesn’t have any mass, but it has momentum.
Momentum is the product of the mass and velocity (p=mv)
It seems contradictory.
Is there an explanation for this, such as an interaction with something else?

Sure there is an explanation. That definition of momentum is only approximate and only applies for particles with v<<c.

In a more modern understanding momentum is the conserved quantity corresponding to spatial-translation symmetry. Thus a field can also have momentum provided that its Lagrangian is invariant wrt spatial translations. You should read up on Noether's theorem.

 

[MattRob]

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

Look, I'll do it now mathematically. If observer is traveling at .9c, then he is traveling at 269,813,212 m/s.

Now to calculate time dilation using the Lorentz equation (Sorry, don't know how to use the fancy math fonts):
L = c / sqrt( c^2 - v^2 )

L = 299,792,458 / sqrt( 299,792,458^2 - 269,813,212^2 )
L = 299,792,458 / sqrt( 89,875,517,873,681,764 - 72,799,169,369,756,944 )
L = 299,792,458 / sqrt( 17,076,348,503,924,820 )
L = 299,792,458 / 130,676,503
L = ~2.294

For every 2.294 seconds of stationary observer time, 1 second of traveling observer time passes. Now, time dilation is accounted for the velocity of the observer, since speed is distance over time. I'll be using the reciprocal, since in this case time is passing at a slower rate for the traveler, while using the raw non-reciprocal would result in the opposite effect.
1/~2.294 = 0.43588989486853601900818999255813

269,813,212 meters / 1 second
Now, correcting for time dilation
269,813,212 meters / 0.43588989486853601900818999255813 second

618,993,959 meters / second

Much faster than 299,792,458 meters a second. From your own perspective, anyways. That is to say, a stationary object will fly by at 618,993,959 meters a second, and you will travel 4 Ly in 1.937 years.

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

And momentum is proportional to mass. And yes, photons do have mass as a matter of fact. E=mc^2, the equation doesn't mean there's a relationship in-between mass and energy, it means mass is energy. "Is", being another word for "equal to".

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.

In it's spare time it will sometimes act like a particle, too. Just has a darned habit of not deciding which one to be.

Can you cite the experiment in question?

That's the darned thing about hearing something interesting somewhere, it's always heck trying to find it again. I think it was to do with early radar experiments, but I'll try to find this and come back to it.

 

[Oudeis Eimi]

And momentum is proportional to mass. And yes, photons do have mass as a matter of fact. E=mc^2, see the "="? It means "equals". The equation doesn't mean there's a relationship in-between mass and energy, it means mass is energy.

Most everything in the above paragraph is wrong.

 

[Dale]

Look, I'll do it now mathematically. If observer is traveling at .9c, then he is traveling at 269,813,212 m/s.

Now to calculate time dilation using the Lorentz equation (Sorry, don't know how to use the fancy math fonts):
L = c / sqrt( c^2 - v^2 )

Sure, but in what way is that the observer's own perspective? From the observer's own perspective he is at rest and his clocks are not time dilated.

And momentum is proportional to mass. And yes, photons do have mass as a matter of fact. E=mc^2, the equation doesn't mean there's a relationship in-between mass and energy, it means mass is energy. "Is", being another word for "equal to".

There are two distinct concepts of "mass" in special relativity. One is called "relativistic mass", that is the mass you are referring to, it is the "mass" that increases as a particle's speed increases. The other is called "invariant mass" or "rest mass", that is the mass that people are referring to when they say that a photon has no mass. In modern physics the unqualified term "mass" usually refers to "invariant mass" and when someone wants to refer to the relativistic mass they generally add the qualifier in order to avoid confusion. The use of relativistic mass is deprecated by most modern physicists.

 

[MattRob]

Sure, but in what way is that the observer's own perspective? From the observer's own perspective he is at rest and his clocks are not time dilated.

No, but by receiving a data stream and referencing it with his own information he can know that he is, in fact, not at rest, and that his clocks are dilated in reference to a stationary observer. (Or, at least the communications facility back on Earth.)

This is really somewhat besides the point though, I'm pretty sure I've made myself clear. It is in fact from his own perspective, as from a stationary observers' perspective, he is traveling at .9c, and not 618,993,959 m/s.

There are two distinct concepts of "mass" in special relativity. One is called "relativistic mass", that is the mass you are referring to, it is the "mass" that increases as a particle's speed increases. The other is called "invariant mass" or "rest mass", that is the mass that people are referring to when they say that a photon has no mass. In modern physics the unqualified term "mass" usually refers to "invariant mass" and when someone wants to refer to the relativistic mass they generally add the qualifier in order to avoid confusion. The use of relativistic mass is deprecated by most modern physicists.

Okay, I'll take that.

But the point of conversation is FTL travel, from a stationary observer's point of view, by finding some loophole in physics. So, to return to that point...

"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."

 

[Dale]

he is, in fact, not at rest

What does this mean? Are you under the mistaken impression that whether or not something is moving has some sort of frame-independent meaning? If not, then what do you mean by "in fact"?

A person is at rest or moving relative to a given frame of reference. In the observer's own frame he is at rest and in any other frame he is moving. There is no coordinate independent sense in which he is "in fact" not at rest.

It is in fact from his own perspective, as from a stationary observers' perspective, he is traveling at .9c, and not 618,993,959 m/s.

He is at rest (0c) from his own perspective, by definition. He is traveling at .9c from someone else's perspective. There is no inertial frame in which he is traveling at any v>c.

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?

Yes, if the laws of physics that we are currently using turn out to be incorrect then it is certainly possible that they might be incorrect in such a way as to allow FTL communication. But then we would be talking about science fiction rather than science.

 

[John232]

Seems to me that the science fiction of FTL travel has already started because of cosmic background radiation showing that the universe expanded FTL. If galaxies can travel FTL with the expansion of space then any type of velocity addition done on them would be false because there is no limit of the rate of speed between them becuase a majority of their motion is defined by the expansion of space itself.

 

[MattRob]

He is at rest (0c) from his own perspective, by definition. He is traveling at .9c from someone else's perspective. There is no inertial frame in which he is traveling at any v>c.

No, but as he reaches .9c from a stationary viewpoint (stationary being an observer set on the surface of any planet, as the velocity of any nearby various body in their orbits is inconsequential relative to relativistic velocities), he will traverse 618,993,959 meters of distance in-between two stationary points every second.

I guess I was wrong to assume I was understood when I meant "at rest" to mean the velocity of any nearby common celestial bodies, the difference in-between which velocities is inconsequential in comparison to the observer's own velocity.

To get it in another time, if he is to leave Earth for Proxima Centauri, which is 4.4 Ly away, at .9c, he will arrive about 1.9 years later from his own perspective, for an average speed of 618,993,959 m/s, which is greater than the given value of c, 299,792,458 m/s. I did the math in my earlier post. However, because of this same time dilation, light will appear to move at 687,723,898.652 m/s, so though the observer strictly isn't going faster than light, he is going faster than 299,792,458 m/s.

Yes, if the laws of physics that we are currently using turn out to be incorrect then it is certainly possible that they might be incorrect in such a way as to allow FTL communication. But then we would be talking about science fiction rather than science.

I always thought the purpose of a hypothesis was to put established science to the test. Seeing as we've never achieved FTL before, at least not to my knowledge, an FTL thread is nothing but a hypothesis, which doesn't necessarily conflict existing science, as much as add to it.

With an attitude of, "if it's not something already established, it's science fiction", with an implied meaning that we can only use established facts, then no hypothesis could be made at all, and science would come to a screeching halt.

It's good to have imagination and come up with new ideas, that's the only way science can progress. The important thing is to test them adequately and correctly, not to not come up with them at all! Scientific advancement only comes through new, wild ideas, like the "strange" idea that the speed of light isn't additive to the velocity of the emitter!

EDIT: Heck, Isaac Newton's idea that gravity works by the inverse of the square was formulated then put away for years because he considered it too outlandish. We're only lucky enough to have discovered it because years later by an astounding coincidence a friend of his asked that exact question.

Anyways, not to assume that the current scientific understanding is wrong, but what is the current scientific understanding on the subject of quantum entanglement and it's use as FTL communication? Was I right that current understanding is that it can't carry information due to randomization?

Or, for that matter, I still have no response to Quantum tunneling as a method of FTL travel.

 

[John232]

We could only hope that science fiction writers do not come up with viable technology in their stories or it could lead to the biggest detourent to scientific progress.

 

[Dale]

I always thought the purpose of a hypothesis was to put established science to the test. ...

With an attitude of, "if it's not something already established, it's science fiction", with an implied meaning that we can only use established facts, then no hypothesis could be made at all, and science would come to a screeching halt.

You are not proposing a hypothesis, you are simply speculating. There is a huge difference. A hypothesis is a quantitative prediction about the measured outcome of a specific experiment. That is why what you were proposing was science fiction, not science.

It's good to have imagination and come up with new ideas, that's the only way science can progress. The important thing is to test them adequately and correctly, not to not come up with them at all!

Sure, and that is the purpose of scientific journals and scientific conferences. That is not the purpose of this site. This site is for learning mainstream physics, not for advancing the state of the art. Please review the rules on overly speculative posts which you agreed to when you signed up.

 

[MattRob]

Sure, and that is the purpose of scientific journals and scientific conferences. That is not the purpose of this site. This site is for learning mainstream physics, not for advancing the state of the art. Please review the rules on overly speculative posts which you agreed to when you signed up.

Wow. Nothing I've said so far is overly speculative. I'm only asking questions to the current state of science. Here's my current unanswered question:
"Anyways, not to assume that the current scientific understanding is wrong, but what is the current scientific understanding on the subject of quantum entanglement and it's use as FTL communication? Was I right that current understanding is that it can't carry information due to randomization?

Or, for that matter, I still have no response to Quantum tunneling as a method of FTL travel."

Breaking 299,792,458 m/s through time dilation is not overly speculative. It's current science. I'm asking the current state of science in regards to certain processes in their use of FTL travel, such as quantum entanglement and tunneling.
In current mainstream physics, is it possible to use Quantum entanglement and tunneling for FTL travel/communications?

 

[Dale]

Seems to me that the science fiction of FTL travel has already started because of cosmic background radiation showing that the universe expanded FTL. If galaxies can travel FTL with the expansion of space then any type of velocity addition done on them would be false because there is no limit of the rate of speed between them becuase a majority of their motion is defined by the expansion of space itself.

Don't take that too seriously. In curved spacetime the relative velocity of distant objects is mathematically ill-defined.

 

[Dale]

Nothing I've said so far is overly speculative.

You don't consider this overly speculative?:

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?

I'm only asking questions to the current state of science

According to the current state of physics there are no tachyons yet discovered nor have any wormholes been discovered. In principle wormholes are not forbidden by GR, I don't know if tachyons are forbidden by the standard model.

 

[MattRob]

Not really, It was a way of asking what the problem is with entangled particles as FTL.

 

[Dale]

Entangled particles don't travel FTL and they don't transmit information FTL. What do you think is FTL about them?

To understand why they don't transmit information let's propose an entangled comm system and see what would happen. Observers A and B have a whole pile of entangled particles which are each entangled for their polarization state. A tries to send a message to B. First A measures a few hundred particles. B measures the entangled particles and gets a 50/50 random distribution. Then A doesn't measure the next few hundred. B measures the entangled particles and gets a 50/50 random distribution. Then A measures a subset of the next few hundred. B measures the entangled particles and gets a 50/50 random distribution.

Nothing that A does changes what B measures. When A and B later reunite they find that all of the particles that A measured are exactly anti-correlated with the particles that B measured, but B has no way of distinguishing the particles that A measured from the ones he didn't.

 

[darkhorror]

To get it in another time, if he is to leave Earth for Proxima Centauri, which is 4.4 Ly away, at .9c, he will arrive about 1.9 years later from his own perspective, for an average speed of 618,993,959 m/s, which is greater than the given value of c, 299,792,458 m/s. I did the math in my earlier post. However, because of this same time dilation, light will appear to move at 687,723,898.652 m/s, so though the observer strictly isn't going faster than light, he is going faster than 299,792,458 m/s.

Your just mixing and matching frames of reference. You use the time in the traveling frame of reference and the distance in the Earth's frame. This doesn't make any sense. How about answering these questions.

So how far did the ship travel?
How long did it take?

 

[DaveC426913]

However, because of this same time dilation, light will appear to move at 687,723,898.652 m/s

No, it will not. Light will still be measured to move at 300,000km/s.

What is true is that he will measure the distance to Centauri to be much shorter than he thought it was when he checked it on Earth.

 

[MattRob]

No, it will not. Light will still be measured to move at 300,000km/s.

What is true is that he will measure the distance to Centauri to be much shorter than he thought it was when he checked it on Earth.

Length contraction? I always thought the object accelerating experiences length contraction. So how does this work?

 

[Dale]

Length contraction? I always thought the object accelerating experiences length contraction. So how does this work?

The acceleration is not relevant, only the relative velocity and your velocity relative to yourself is always 0.

Nothing "experiences" length contraction, meaning that you never measure yourself to be length contracted. In your own frame you are never length contracted nor time dilated. It is always the moving clock or rod which is length contracted or time dilated in your frame.