The Underlying Problem With Some Science Is Interpretation.

[OceanBreeze]

 

 

 

There is no contradiction, you just need to go back to basics and try to understand how difference frames of reference work. All observers observer the same velocity of light relative to themselves but not to other objects. In other words light always moves past YOU at c (providing you're not accelerating) but it will move past other objects at velocities other than c in your frame of reference if those objects are in motion relative to you.

 

 

 

 

Great! Now you have made it crystal clear what your problem is.

 

This is sad and hilariously funny at the same time. Sorry, I can’t help you anymore.

You are going to have to get over this mental block (known as cognitive dissonance) all by yourself.

 

I will just leave you with a few closing statements, and cite the sources for each, Pay particular attention to number 3 because it directly contradicts what you wrote and I quoted you on, above.

 

1) the rules for adding up relative velocities change in special relativity. In "common-sense" physics (ie. the realm that we're used to deal with), if the bus is moving at speed v and a person in it is moving at speed u relative to the bus (and in the same direction) then the persons speed relative to the ground is just w = u+v.

This is called the Galillean transformation. In the theory of special relativity though, the speed relative to the ground becomes w = (u + v)/(u*v/c*c + 1)

 

(now a Lorenztian transformation) so you can see that even if u=c and v=c then w = c! You can't go faster than c relative to anything! Source here.

 

2) One of the basic postulates of special relativity: The speed of light in a vacuum is the same for all observers drifting through gravity-free space (more precisely: for all inertial observers. In particular, its value its independent of an observer's motion relative to the source of the light. Source here.

 

3) Essentially, then, the Special Theory of Relativity can be boiled down to its two main postulates: firstly, that physical laws have the same mathematical form when expressed in any inertial system (so that all motion, and the forces that result from it, is relative); and secondly that the speed of light is independent of the motion of its source and of the observer, and so it is NOT relative to anything else and will always have the same value when measured by observers moving with constant velocity with respect to each other. Source here

 

I will leave it to you to figure out how this makes your statements quoted here, ridiculously wrong.

[OceanBreeze]

No, of course not, name calling is not acceptable. Respect the opinions of others. Don’t be rude and offensive. Etc. Seriously.

 

This thread has some good concepts in it, but they’re buried and obscured by heaps of ad hominem action and reaction. Nobody should call anybody a “punk”, “really pathetic”, or other things in this vein. Everyone, please be polite!

 

Correct, the rate of change in distance between 2 bodies is not a velocity. A velocity consists of a speed and a direction, both of which are relative to a frame of reference.

 

Distances between bodies and their rate of change are very useful (for example, in simulations like the one in this 10-year-old thread), but they’re technically neither speeds nor velocities.

 

 

Sorry about all that, it was, as you say “action and reaction” but I should have known better than to get drawn into all of that. If nothing else, this thread gave you an opportunity to showcase your awesome LaTex skills!

 

More seriously, as a admin/moderator, it might be helpful for you to take a position on the claim by A-wal, that the velocity of Light with respect to some object B as seen by observer A, is anything other than c. All sources you can find anywhere will say that c is invariant, that is, it is always c, as seen by any inertial observer and with respect to any other inertial observer. Invariant means it cannot be anything else.

 

A-wal is claiming there is a relative velocity of LIGHT with respect to B, as seen by A is 0.5c. He also claims the relative velocity of Light, with respect to A, as seen by B is 1.5c.

 

I am interested in knowing what you think about that,  Craig? (or would you rather not say?)

Please read my previous post, especially item 3

[HydrogenBond]

He's quite right, actually.  What a strange thing to disagree with.

What we see, in relative motion, is limited by the light/photons that moves between objects and references. Our eyes needs photons to be able to see. Even if two objects appear to move faster than C relative to each other, based on math, the light energy from the objects always travels at C to us and between each other. 

 

As an analogy, say you had a process that can make widgets at the rate of 60 per hour. Even if we improve the next step in the manufacturing process, such as paint the widgets,  so it can paint 120 units per hour, the assembly line still becomes limited by the previous step of 60 per hour. We can never make full use of the second step when the previous step is rate limiting. 

 

Beyond seeing energy emissions, from moving objects, we have no other means to observe, therefore we can never see anything that moves faster than C. It will always seem to peak at C, due to the nature of photons, and the needs of the eyes. It is nothing magical just rate limited by the photons and speed of light. 

 

This has to do with the rules of science and evidence, with the speed of light limiting the evidence. To go faster that C, we need to begin speculating and inferring, and can never show direct visual data, since light/energy peaks at C. The evidence we can present, would need to be without energy so we don't have these limits. Then that gets sticky and will called speculation or theory. 

Edited January 13, 2017 by HydrogenBond

[sluggo]

1. In the 1900's the term 'velocity' was synonymous with 'speed'. This is revealed in the publications of SR by A. Einstein and his contemporary Max Born. Direction is mentioned  separately and in addition to velocity.

A line from the 1905 paper, part1, par 3:

"From reasons of symmetry it is now evident that the length of a given rod moving perpendicularly to its axis, measured in the stationary system, must depend only on the velocity and not on the direction and the sense of the motion."

Direction was indicated with (±).

2. Using the formal definition of velocity as a vector, composed of magnitude and direction, the term "closing speed" should avoid any misunderstanding. In the course of clarification by others an expanding or contracting space has no direction and is not an instance of momentum (mass in motion), and therefore not subject to SR. Also in the 1905 paper, there are multiple occurrences of x/(c-v) and x/(c+v), i.e. distance/(gap* speed). (Some one may want to report this supposed violation of SR.) Unfortunately the author left the country without leaving a forwarding address and can't appear to defend himself.
 *This is the shortest word I've found without having to define in terms of size progression.
 

[A-wal]

What we see, in relative motion, is limited by the light/photons that moves between objects and references. Our eyes needs photons to be able to see. Even if two objects appear to move faster than C relative to each other, based on math, the light energy from the objects always travels at C to us and between each other. 

 

As an analogy, say you had a process that can make widgets at the rate of 60 per hour. Even if we improve the next step in the manufacturing process, such as paint the widgets,  so it can paint 120 units per hour, the assembly line still becomes limited by the previous step of 60 per hour. We can never make full use of the second step when the previous step is rate limiting. 

 

Beyond seeing energy emissions, from moving objects, we have no other means to observe, therefore we can never see anything that moves faster than C. It will always seem to peak at C, due to the nature of photons, and the needs of the eyes. It is nothing magical just rate limited by the photons and speed of light. 

 

This has to do with the rules of science and evidence, with the speed of light limiting the evidence. To go faster that C, we need to begin speculating and inferring, and can never show direct visual data, since light/energy peaks at C. The evidence we can present, would need to be without energy so we don't have these limits. Then that gets sticky and will called speculation or theory. 

No, it's got nothing to with with not being able to perceive the light from objects that are moving at over c, it's that the speed of light is the same for all inertial observers which leads to time dilation and length contraction that prevents any object from reaching the speed of light relative to any observer.

 

Using the formal definition of velocity as a vector, composed of magnitude and direction, the term "closing speed" should avoid any misunderstanding.

That really isn't the issue though. He actually believes that light moves at 1c relative to all objects from the perspective of other objects that are in motion relative to them!

 

Sorry about all that, it was, as you say “action and reaction” but I should have known better than to get drawn into all of that.

You haven't been drawn into anything. You reacted childishly on three occasions when the stupidity of your conceptions were pointed out, twice by me and once by Sluggo and on each occasion you were the instigator in the silliness that followed.

 

More seriously, as a admin/moderator, it might be helpful for you to take a position on the claim by A-wal, that the velocity of Light with respect to some object B as seen by observer A, is anything other than c. All sources you can find anywhere will say that c is invariant, that is, it is always c, as seen by any inertial observer and with respect to any other inertial observer. Invariant means it cannot be anything else.

 

A-wal is claiming there is a relative velocity of LIGHT with respect to B, as seen by A is 0.5c. He also claims the relative velocity of Light, with respect to A, as seen by B is 1.5c.

 

I am interested in knowing what you think about that,  Craig? (or would you rather not say?)

Please read my previous post, especially item 3

He can't help you either, no one can. You've dug yourself far too deep.

 

The physics of vector equations, in four dimensions will get to the heart of  ‘Einsteinian’ physics, the real physics, the relativistic correct physics.

 

So if you can’t understand now, at this time, what the difference is between a vector , that is velocity, and a scalar, that is speed, you have no hope of ever understanding relativity.

 

The Galilean/Newtonian equations are on the Right, and the Einsteinian/Lorentzian equations on the Left.

 

 

This is what you are going to be doing if you want to work with Special Relativity.

 

What we have been discussing so far is child’s play, yet some people here cannot handle it, and that is OK, as long as you are willing to learn. When you have been shown to be wrong, start by admitting it, at least to yourself, and then try to learn the correct way.

Those who understand something make it simple, those who don't always try to make it more complicated. The correct approach would be for you to understand the basics before trying to hide behind equations that you have no clue how to apply to real situations.

 

Great! Now you have made it crystal clear what your problem is.

 

This is sad and hilariously funny at the same time. Sorry, I can’t help you anymore.

You are going to have to get over this mental block (known as cognitive dissonance) all by yourself.

Oh okay. :)

 

I will just leave you with a few closing statements, and cite the sources for each, Pay particular attention to number 3 because it directly contradicts what you wrote and I quoted you on, above.

It really doesn't.

 

1) the rules for adding up relative velocities change in special relativity. In "common-sense" physics (ie. the realm that we're used to deal with), if the bus is moving at speed v and a person in it is moving at speed u relative to the bus (and in the same direction) then the persons speed relative to the ground is just w = u+v.

This is called the Galillean transformation. In the theory of special relativity though, the speed relative to the ground becomes w = (u + v)/(u*v/c*c + 1)

 

(now a Lorenztian transformation) so you can see that even if u=c and v=c then w = c! You can't go faster than c relative to anything! Source here.

 

2) One of the basic postulates of special relativity: The speed of light in a vacuum is the same for all observers drifting through gravity-free space (more precisely: for all inertial observers. In particular, its value its independent of an observer's motion relative to the source of the light. Source here.

 

3) Essentially, then, the Special Theory of Relativity can be boiled down to its two main postulates: firstly, that physical laws have the same mathematical form when expressed in any inertial system (so that all motion, and the forces that result from it, is relative); and secondly that the speed of light is independent of the motion of its source and of the observer, and so it is NOT relative to anything else and will always have the same value when measured by observers moving with constant velocity with respect to each other. Source here

Once again, the velocity addition formula applies to objects that are in motion relative to the observer, NOT objects that are in motion relative to each other from the perspective of the observer! The speed of light is the same for all inertial observers from their own perspective, it obviously doesn't apply to the speed of light relative to objects that are in motion relative to the observer. It's not explicitly stated because it's very hard to imagine anyone being capable of making this mistake. When I said it's the most fundamental error I've seen of somebody who's under the impression that they understand SR I wasn't saying it just to be an arsehole.

 

The speed of light is always the same from the perspective of an inertial observer so we start with Observer A and a beam of light that passes them at the speed of light. Staying in Observer A's frame of reference, Observer B is moving away from Observer A at half the speed of light, so in Observer A's frame of reference the light is passing Observer A at 1c and heading towards Observer B who is moving away from Observer A at 0.5c. If what you were claiming was true then the light would have to increase it's speed relative to Observer A so that it passes Observer B at 1c from Observer A's frame of reference, meaning that the speed of light wouldn't be constant.

 

How do you believe this works? Is it a gradual increase in speed as the light approaches Observer B or does it suddenly double its velocity when it gets to within a certain distance of Observer B? What happens if another object is moving away from Observer B, how does the light change its velocity from in Observer A's frame of reference so that it's moving at 1c relative to both objects from Observer A's perspective? Are you beginning to see how stupid this is now? Do you think maybe the light only moves past Observer B at the speed of light from Observer B's perspective?

 

Objects that are motion relative to an observer are time dilated and length contracted in the frame of reference of that observer so if you want to switch frames to an observer that's in motion relative to the initial object then you apply the Lorenz transformations and this is what causes the non-linear velocity addition formula from SR. It does NOT apply to other objects that are motion relative to each other in the frame of reference of an observer! Light moves at 1c relative to all inertial observers so if Observer B is moving away from Observer A at 0.5c then light moving in the same direction will move past Observer B at 0.5c in Observer A's frame of reference.

 

I will leave it to you to figure out how this makes your statements quoted here, ridiculously wrong.

This is how stupid your claim really is. In this example Observer B passes Observer A at the same time that the light passes both Observers, how can the light possibly be moving at 1c relative to Observer B from Observer A's perspective if the light is moving past Observer A at 1c from Observer A's perspective and Observer B is moving at 0.5c in the same direction?

[OceanBreeze]

 

 

 The correct approach would be for you to understand the basics before trying to hide behind equations that you have no clue how to apply to real situations.

 

Once again, the velocity addition formula applies to objects that are in motion relative to the observer, NOT objects that are in motion relative to each other from the perspective of the observer! The speed of light is the same for all inertial observers from their own perspective, it obviously doesn't apply to the speed of light relative to objects that are in motion relative to the observer. It's not explicitly stated because it's very hard to imagine anyone being capable of making this mistake. When I said it's the most fundamental error I've seen of somebody who's under the impression that they understand SR I wasn't saying it just to be an arsehole.

 

The speed of light is always the same from the perspective of an inertial observer so we start with Observer A and a beam of light that passes them at the speed of light. Staying in Observer A's frame of reference, Observer B is moving away from Observer A at half the speed of light, so in Observer A's frame of reference the light is passing Observer A at 1c and heading towards Observer B who is moving away from Observer A at 0.5c. If what you were claiming was true then the light would have to increase it's speed relative to Observer A so that it passes Observer B at 1c from Observer A's frame of reference, meaning that the speed of light wouldn't be constant.

 

 

Objects that are motion relative to an observer are time dilated and length contracted in the frame of reference of that observer so if you want to switch frames to an observer that's in motion relative to the initial object then you apply the Lorenz transformations and this is what causes the non-linear velocity addition formula from SR. It does NOT apply to other objects that are motion relative to each other in the frame of reference of an observer! Light moves at 1c relative to all inertial observers so if Observer B is moving away from Observer A at 0.5c then light moving in the same direction will move past Observer B at 0.5c in Observer A's frame of reference.

 

This is how stupid your claim really is. In this example Observer B passes Observer A at the same time that the light passes both Observers, how can the light possibly be moving at 1c relative to Observer B from Observer A's perspective if the light is moving past Observer A at 1c from Observer A's perspective and Observer B is moving at 0.5c in the same direction?

 

 

 

So nice to see you back, A-wal!

 

At this point, I am beginning to pity you. You can melt down all you want, throw more insults my way, even disparage the math that you do not understand, but you are still wrong.

 

As usual, I provide another link to show you are wrong, and, as usual, you provide another inane assertion that you are right. It really is boring, but I can’t let you post your wrongness on this forum without correcting you.

 

So, from the link and with my bold emphasis and comments added in red:

 

Quote

 

"The Principle of Relativity states that if K and K' are both Galilean coordinate systems, then all natural phenomena behave precisely the same in K as in K'.

With me so far? OK, that last statement, the Principle of Relativity (I'll call it "PR" from now on to save typing), means that rules don't change just because you're moving. This has been demonstrated to be true many, many times, and good thing too. If relative motion affected the laws of physics, then you'd have to worry about things like where the Earth is in its orbit, or where you happen to be standing on it, before you could figure out things like velocity or acceleration.

 

Starting with these definitions and observations, Einstein began a thought exercise. He contemplated a long, straight rail line, and a rather long train traveling at a constant speed along that line. Someone standing on the ground beside the railway is in one Galilean frame of reference, K; while another person standing on the moving train is in another Galilean system, K'. We know that physical laws must behave the same for both people.

 

Here's where the fun begins.

 

Imagine the man on the ground observing the passenger in the train. The passenger is walking in the same direction as the train, also with a constant velocity. Classical mechanics states that in order to determine the velocity of the passenger with respect to the observer on the ground (call that velocity W), you merely add the velocity of the train, v, and the velocity of the passenger with respect to the train, w. That is: W = v + w   {this is what YOU are claiming, A-wal, whether you realize it or not}

 

Seems simple, yes? Well, there's a problem. Light is a natural phenomenon. The speed of light in a vacuum is a constant 300,000 km/s (called 'c'). Many experiments have been done which demonstrate incontrovertibly that the speed of light does NOT depend on the speed of the body which emits that light. It is truly constant, regardless of relative motion.

 

[side note: When a light-emitting body, like a star or galaxy, is moving very quickly either towards or away from us we see a change in the WAVELENGTH of the light that reaches us, but regardless of the color the light itself always travels at c.]

But if c is constant regardless of relative motion, what about the passenger on the train carrying a flashlight? Obviously for the passenger the light leaving his flashlight travels at c. But - and this is the important part - the observer standing on the ground sees the light leaving the flashlight moving at c as well, NOT v + c, as classical mechanics would predict. {This is what you are fighting against, A-wal, if your "theory" was right, the observer on the ground would see the light moving away from the flashlight at c - v, but he doesn't}

 

 So it looked to physicists like either the PR was invalid, or c was not constant. But repeated experiments showed that both were, in fact, true. This is exactly the sort of conflict that keeps physicists up nights. Einstein's breakthrough was in realizing that there are some implicit assumptions in classical mechanics. Specifically, classical mechanics assumes that both space (that is, the distance between two points attached to a rigid body) and time are invariant. Einstein started with the two things that had been proved true by experiment (c and the PR), allowed the others to fall by the wayside, and followed the logic to see where it would lead.

 

He started by imagining three points on the stationary railway line: A and B, which are far away from each other, and C which lies halfway in between. At the point C we place our observer standing on the ground, and we have a second observer standing on the moving train. The standing observer sees lightning strike the rails at points A and B simultaneously, as the observer on the train also passes point C. Does the observer on the train also see simultaneous flashes?

In fact, he doesn't. Because the speed of light is finite and invariant, and because he is moving toward point B, he sees the flash from point B before the flash from A - so for him the events are NOT simultaneous, despite the fact that he passes point C at the same time that observer A sees simultaneous flashes.

 

Einstein used this simple thought exercise to demonstrate that both time and space are altered for the moving observer with respect to the standing one. The math involved is actually rather simple. Here's the result:

In classical mechanics, coordinates in the K frame can be transformed into coordinates in the K' from using the Galilean transformation equations:

 

x' = x-vt    z' = z

 

y' = y        t' = t

 

These are the equations that lead to the velocity addition problem when c is invariant. Einstein found that by following the results of his logical argument, the transformation consistent with PR is actually the Lorenz transformation:

 

{This is the math you are disparaging, because you have no hope of understanding it}

 

x' = (x-vt)/sqrt(1-(v^2/c^2))  [ ^ = exponentiation ]

 

y' = y

 

z' = z

 

t' = (t-(vx/c^2))/sqrt(1-(v^2/c^2))

 

Note that when v is much, much smaller than c, you get the Galilean transformation equations as a good approximation. The accuracy of these equations has been demonstrated by experiments, most notably by Fizeau, who measured the speed of light in moving fluids (the speed of light through any particular medium is a physical invariant). The Lorenz transformations actually were developed by Lorenz in studying electrodynamics (light is an electromagnetic phenomenon) before Einstein started contemplating trains and lightning.

 

End Qoute

 

What this all means is the velocity of light is invariant. There is never a velocity of light relative to anything that is other than c. It is not because of some mathematical device, it is because time and space, or space-time, changes when there is relative motion. And that change occurs even at slow velocities, it is just that the change is so small we don’t notice it until the velocity is a significant fraction of c.

 

All you need to do, to solve your problem, is learn to add velocities as Einstein did and stop adding them as Galileo did, when the velocities are very high. W = v + w  , that you insist on applying to LIGHT is wrong! In fact, this method of adding velocities is only an approximation, and is only valid for the low velocities that we encounter every day. It is not valid when you are talking about Light!

 

Read the source I linked and if you disagree with it, then write to them and tell them about your theory. I am sure they will be interested in hearing from you.

 

OR, you can have another meltdown. It is entertaining!

[A-wal]

Everything you post that isn't a tantrum is either an ad hominem personal attack or a strawman.
 

So nice to see you back, A-wal!

 

At this point, I am beginning to pity you. You can melt down all you want, throw more insults my way, even disparage the math that you do not understand, but you are still wrong.

I'm not disparaging any mathematics, only your understanding of it because you're using it wrong by applying to objects that are in motion relative to each in the frame of reference of the observer.

 

As usual, I provide another link to show you are wrong, and, as usual, you provide another inane assertion that you are right. It really is boring, but I can’t let you post your wrongness on this forum without correcting you.

As usual you completely ignore all the points I make just like xyz and provide nothing but strawmen.

 

Quote

 

"The Principle of Relativity states that if K and K' are both Galilean coordinate systems, then all natural phenomena behave precisely the same in K as in K'.

With me so far? OK, that last statement, the Principle of Relativity (I'll call it "PR" from now on to save typing), means that rules don't change just because you're moving. This has been demonstrated to be true many, many times, and good thing too. If relative motion affected the laws of physics, then you'd have to worry about things like where the Earth is in its orbit, or where you happen to be standing on it, before you could figure out things like velocity or acceleration.

 

Starting with these definitions and observations, Einstein began a thought exercise. He contemplated a long, straight rail line, and a rather long train traveling at a constant speed along that line. Someone standing on the ground beside the railway is in one Galilean frame of reference, K; while another person standing on the moving train is in another Galilean system, K'. We know that physical laws must behave the same for both people.

 

Here's where the fun begins.

 

Imagine the man on the ground observing the passenger in the train. The passenger is walking in the same direction as the train, also with a constant velocity. Classical mechanics states that in order to determine the velocity of the passenger with respect to the observer on the ground (call that velocity W), you merely add the velocity of the train, v, and the velocity of the passenger with respect to the train, w. That is: W = v + w   {this is what YOU are claiming, A-wal, whether you realize it or not}

 

Seems simple, yes? Well, there's a problem. Light is a natural phenomenon. The speed of light in a vacuum is a constant 300,000 km/s (called 'c'). Many experiments have been done which demonstrate incontrovertibly that the speed of light does NOT depend on the speed of the body which emits that light. It is truly constant, regardless of relative motion.

 

[side note: When a light-emitting body, like a star or galaxy, is moving very quickly either towards or away from us we see a change in the WAVELENGTH of the light that reaches us, but regardless of the color the light itself always travels at c.]

But if c is constant regardless of relative motion, what about the passenger on the train carrying a flashlight? Obviously for the passenger the light leaving his flashlight travels at c. But - and this is the important part - the observer standing on the ground sees the light leaving the flashlight moving at c as well, NOT v + c, as classical mechanics would predict. {This is what you are fighting against, A-wal, if your "theory" was right, the observer on the ground would see the light moving away from the flashlight at c - v, but he doesn't}

 

 So it looked to physicists like either the PR was invalid, or c was not constant. But repeated experiments showed that both were, in fact, true. This is exactly the sort of conflict that keeps physicists up nights. Einstein's breakthrough was in realizing that there are some implicit assumptions in classical mechanics. Specifically, classical mechanics assumes that both space (that is, the distance between two points attached to a rigid body) and time are invariant. Einstein started with the two things that had been proved true by experiment (c and the PR), allowed the others to fall by the wayside, and followed the logic to see where it would lead.

 

He started by imagining three points on the stationary railway line: A and B, which are far away from each other, and C which lies halfway in between. At the point C we place our observer standing on the ground, and we have a second observer standing on the moving train. The standing observer sees lightning strike the rails at points A and B simultaneously, as the observer on the train also passes point C. Does the observer on the train also see simultaneous flashes?

In fact, he doesn't. Because the speed of light is finite and invariant, and because he is moving toward point B, he sees the flash from point B before the flash from A - so for him the events are NOT simultaneous, despite the fact that he passes point C at the same time that observer A sees simultaneous flashes.

 

Einstein used this simple thought exercise to demonstrate that both time and space are altered for the moving observer with respect to the standing one. The math involved is actually rather simple. Here's the result:

In classical mechanics, coordinates in the K frame can be transformed into coordinates in the K' from using the Galilean transformation equations:

 

x' = x-vt    z' = z

 

y' = y        t' = t

 

These are the equations that lead to the velocity addition problem when c is invariant. Einstein found that by following the results of his logical argument, the transformation consistent with PR is actually the Lorenz transformation:

 

{This is the math you are disparaging, because you have no hope of understanding it}

 

x' = (x-vt)/sqrt(1-(v^2/c^2))  [ ^ = exponentiation ]

 

y' = y

 

z' = z

 

t' = (t-(vx/c^2))/sqrt(1-(v^2/c^2))

 

Note that when v is much, much smaller than c, you get the Galilean transformation equations as a good approximation. The accuracy of these equations has been demonstrated by experiments, most notably by Fizeau, who measured the speed of light in moving fluids (the speed of light through any particular medium is a physical invariant). The Lorenz transformations actually were developed by Lorenz in studying electrodynamics (light is an electromagnetic phenomenon) before Einstein started contemplating trains and lightning.

 

End Qoute

All of this is a strawman that in no way validates your position. What do you believe supports your misconception that light moves past objects that are in motion relative an observer at the same speed that it moves relative to that observer. I still can't believe you think that it even makes any kind of sense.

 

What this all means is the velocity of light is invariant. There is never a velocity of light relative to anything that is other than c. It is not because of some mathematical device, it is because time and space, or space-time, changes when there is relative motion. And that change occurs even at slow velocities, it is just that the change is so small we don’t notice it until the velocity is a significant fraction of c.

 

All you need to do, to solve your problem, is learn to add velocities as Einstein did and stop adding them as Galileo did, when the velocities are very high. W = v + w  , that you insist on applying to LIGHT is wrong! In fact, this method of adding velocities is only an approximation, and is only valid for the low velocities that we encounter every day. It is not valid when you are talking about Light!

This is getting really silly. The consistency of the speed of relative relative to all inertial observers does NOT mean that the speed of light is the same relative to objects that are in motion relative to the observer! How could that possibly work?

 

Read the source I linked and if you disagree with it, then write to them and tell them about your theory. I am sure they will be interested in hearing from you.

They'd be confused as to why I'm arguing against something that they never claimed to be true. Everything I've said in this topic is completely consistent with the special theory of relativity. You're the one who's using your own theory without realising it trying to apply to situations that are outside of the framework of what theory describes.

Nothing in the special theory of relativity supports your view because your view is simply a misconception about how the model works and makes absolutely no sense.

 

OR, you can have another meltdown. It is entertaining!

What are talking about? You think my last post constitutes a meltdown? It's one of the most clear and concise posts I've written. Or do you mean not replying until now? I needed a break from this type of argument, with you and xyz is was too much but he's gone now so we're back to just one of you. I can handle that.

Your claim is no less stupid than his was. He believed that the consistency of the speed of light relative to all inertial observers somehow doesn't lead to time dilation and length contraction. You believe that the consistency of the speed of light not only applies to the observer but also from the observer's frame of reference to objects that are in motion relative to the observer.

 

Once again, the velocity addition formula applies to objects that are in motion relative to the observer, NOT objects that are in motion relative to each other from the perspective of the observer! The speed of light is the same for all inertial observers from their own perspective, it obviously doesn't apply to the speed of light relative to objects that are in motion relative to the observer. It's not explicitly stated because it's very hard to imagine anyone being capable of making this mistake. When I said it's the most fundamental error I've seen of somebody who's under the impression that they understand SR I wasn't saying it just to be an arsehole.

The speed of light is always the same from the perspective of an inertial observer so we start with Observer A and a beam of light that passes them at the speed of light. Staying in Observer A's frame of reference, Observer B is moving away from Observer A at half the speed of light, so in Observer A's frame of reference the light is passing Observer A at 1c and heading towards Observer B who is moving away from Observer A at 0.5c. If what you were claiming was true then the light would have to increase it's speed relative to Observer A so that it passes Observer B at 1c from Observer A's frame of reference, meaning that the speed of light wouldn't be constant.

How do you believe this works? Is it a gradual increase in speed as the light approaches Observer B or does it suddenly double its velocity when it gets to within a certain distance of Observer B? What happens if another object is moving away from Observer B, how does the light change its velocity from in Observer A's frame of reference so that it's moving at 1c relative to both objects from Observer A's perspective? Are you beginning to see how stupid this is now? Do you think maybe the light only moves past Observer B at the speed of light from Observer B's perspective?

Objects that are motion relative to an observer are time dilated and length contracted in the frame of reference of that observer so if you want to switch frames to an observer that's in motion relative to the initial object then you apply the Lorenz transformations and this is what causes the non-linear velocity addition formula from SR. It does NOT apply to other objects that are motion relative to each other in the frame of reference of an observer! Light moves at 1c relative to all inertial observers so if Observer B is moving away from Observer A at 0.5c then light moving in the same direction will move past Observer B at 0.5c in Observer A's frame of reference.

 

This is how stupid your claim really is. In this example Observer B passes Observer A at the same time that the light passes both Observers, how can the light possibly be moving at 1c relative to Observer B from Observer A's perspective if the light is moving past Observer A at 1c from Observer A's perspective and Observer B is moving at 0.5c in the same direction?

Don't evade, defend!

Edited January 21, 2017 by A-wal

[OceanBreeze]

 

 What do you believe supports your misconception that light moves past objects that are in motion relative an observer at the same speed that it moves relative to that observer. I still can't believe you think that it even makes any kind of sense.

 

This is getting really silly. The consistency of the speed of relative relative to all inertial observers does NOT mean that the speed of light is the same relative to objects that are in motion relative to the observer! How could that possibly work?

 

 

 

I see! You have chosen Option B, another incoherent meltdown. This happens to people with cog dis, you know.

 

 

How can it possibly work, you ask? So what about the flashlight? Both observers see the light moving away from the flashlight at velocity c.

 

That is, the light moves at c as observed by the observer A who is holding the flashlight in his inertial frame, moving at v. And the stationary observer, B who is in an inertial frame that is at rest with respect to observer A, also sees the light moving away from the flashlight at c.

 

This is exactly what you are denying! You think the velocity of light is relative to different observers, according to the relative motion between them. You have made that crystal clear!

 

I have refuted you and provided many references. I have nothing to defend to you! But you have a lot of assertions to defend, that you can’t! The speed of Light is INVARIANT!

 

Try letting that fact sink into your thick head. It cannot be more clearly expressed that this:

 

 Essentially, then, the Special Theory of Relativity can be boiled down to its two main postulates: firstly, that physical laws have the same mathematical form when expressed in any inertial system (so that all motion, and the forces that result from it, is relative); and secondly that the speed of light is independent of the motion of its source and of the observer, and so it is NOT relative to anything else and will always have the same value when measured by observers moving with constant velocity with respect to each other. Source here

 

 

The fact is, as I said earlier, you have, at best, only a superficial idea of what Einstein’s Theory of Special Relativity is, and you refuse to learn anything that will contradict your rather bizarre ideas.

No matter how many references I cite that support me, and none that support you, you still think you are right.

 

I have tried my best to help you, but you can’t be helped. Did you ever find out what the “d” means in a differential equation?

 

 

Now, please go ahead and have another rant and meltdown. That’s always good for a laugh.

 

Side Note; If Craig doesn’t have the balls to step in and tell you how wrong you are, that is his problem.

Lately he is letting trolls run rampant here, with Delburt Phend still denying conservation of energy and using linear momentum to “solve” a problem in rotational dynamics, and yet another troll who thinks geostationary satellites are fake and the moon is in low earth orbit!

 

It is all very humorous, but at some point Craig and Sanctus need to decide if they want a science forum, or a science joke troll forum. Right now, I suspect it is the latter, and if so, I may just as well join in with the trolling, or just leave.

 

In fact, to help accelerate my leaving, I just have to say you are an IDIOT! And Craig has no balls to take any action to correct you.

 

 Sanctus is a good admin and it would be best if Craig would step aside and let Sanctus sort this place out. If that includes banning me, I am all for it.

[A-wal]

I see! You have chosen Option B, another incoherent meltdown.

Huh? Looking at the difference between posts made by the two of us I think it's very clear which of us is having a 'meltdown'.

 

I see! You have chosen Option B, another incoherent meltdown. This happens to people with cog dis, you know.

Yes I can see that.

 

How can it possibly work, you ask? So what about the flashlight? Both observers see the light moving away from the flashlight at velocity c.

 

That is, the light moves at c as observed by the observer A who is holding the flashlight in his inertial frame, moving at v. And the stationary observer, B who is in an inertial frame that is at rest with respect to observer A, also sees the light moving away from the flashlight at c.

Of course they both see the light moving at c relative to themselves because the speed of light is constant for all inertial observers.

 

This is exactly what you are denying! You think the velocity of light is relative to different observers, according to the relative motion between them. You have made that crystal clear!

It is. The speed of light is the same relative to all inertial observers, but from the perspective of an observer it's not the same relative to objects that are in motion relative to them.

 

To think that light can move past all objects at the same speed from the perspective of every inertial observer is very unique misconception that I've never come across before. I have no idea how you could make that model work, it's just not anywhere near even close to making any sense, which is how I know that you have no understanding of this topic and are either quoting or just repeating what you read but applying it completely out of its intended context.

 

I have refuted you and provided many references. I have nothing to defend to you! But you have a lot of assertions to defend, that you can’t! The speed of Light is INVARIANT!

The references you've provided don't support your arguments, they support mine. In fact you haven't even made an argument, the references are your arguments but your misunderstanding them. The speed of light is only invariant in the sense that it always move at the same rate relative to inertial observers in their own frame of reference, not in the sense that it is somehow able to magically move at the same rate without changing reference frames relative objects that are in motion relative to each other.

 

You can only adjust the speed of light to c relative to an object that's in motion relative to the observer if you change to the reference frame of that object. That change of reference frame is what causes time dilation and length contraction to be accounted for and leads to the velocity addition formula that you think is used on objects that are in motion relative to each other from the perspective of the observer without changing the reference frame to one of those objects.

 

Try letting that fact sink into your thick head. It cannot be more clearly expressed that this:

 

 Essentially, then, the Special Theory of Relativity can be boiled down to its two main postulates: firstly, that physical laws have the same mathematical form when expressed in any inertial system (so that all motion, and the forces that result from it, is relative); and secondly that the speed of light is independent of the motion of its source and of the observer, and so it is NOT relative to anything else and will always have the same value when measured by observers moving with constant velocity with respect to each other. Source here

Yes it will always have the same value relative to all inertial observers, but that doesn't mean that it moves at the same rate relative to all inertial objects in the frame of reference of those observers. Light moves at c relative to all of them in their own frame of reference but it obviously moves at different rates relative to objects that are in motion relative to an observer.

 

The fact is, as I said earlier, you have, at best, only a superficial idea of what Einstein’s Theory of Special Relativity is, and you refuse to learn anything that will contradict your rather bizarre ideas.

No matter how many references I cite that support me, and none that support you, you still think you are right.

None of those references in any way support your claim. You'll never find one that does because your claim is nonsensical bollocks.

 

I have tried my best to help you, but you can’t be helped. Did you ever find out what the “d” means in a differential equation?

You told me what it means, or google/bing did. I still think it could be done with just algebra. I don't trust it when there's a value in there that doesn't represent anything physical but I don't know the maths anywhere near well enough to debate it. This has nothing to do with the issue.

 

Now, please go ahead and have another rant and meltdown. That’s always good for a laugh.

I'm not ranting or melting down. I think this qualifies though.

Side Note; If Craig doesn’t have the balls to step in and tell you how wrong you are, that is his problem.

Lately he is letting trolls run rampant here, with Delburt Phend still denying conservation of energy and using linear momentum to “solve” a problem in rotational dynamics, and yet another troll who thinks geostationary satellites are fake and the moon is in low earth orbit!

 

It is all very humorous, but at some point Craig and Sanctus need to decide if they want a science forum, or a science joke troll forum. Right now, I suspect it is the latter, and if so, I may just as well join in with the trolling, or just leave.

 

In fact, to help accelerate my leaving, I just have to say you are an IDIOT! And Craig has no balls to take any action to correct you.

 

 Sanctus is a good admin and it would be best if Craig would step aside and let Sanctus sort this place out. If that includes banning me, I am all for it.

Edited January 21, 2017 by A-wal

[OceanBreeze]

 

 

 

OceanBreeze, on 21 Jan 2017 - 8:43 PM, said:

 

How can it possibly work, you ask? So what about the flashlight? Both observers see the light moving away from the flashlight at velocity c.

 

That is, the light moves at c as observed by the observer A who is holding the flashlight in his inertial frame, moving at v. And the stationary observer, B who is in an inertial frame that is at rest with respect to observer A, also sees the light moving away from the flashlight at c.

 

Of course they both see the light moving at c relative to themselves because the speed of light is constant for all inertial observers.

 

 

 

 

Right there, is your problem. Your cog dis is so bad you can't even read the words for comprehension.

 

It says: the stationary observer, B who is in an inertial frame that is at rest with respect to observer A, also sees the light moving away from the flashlight at c.

 

You are saying: "Yes it will always have the same value relative to all inertial observers, but that doesn't mean that it moves at the same rate relative to all inertial objects in the frame of reference of those observers"

 

Do you understand the flashlight is an object, and it is in the frame of observer A? Do you understand the light is moving away from that object at c? Do you also understand that stationary observer B sees the light moving away from the flashlight at c, even though the flashlight is in motion with respect to him?

 

Now tell me again how that agrees with your claim that "Light moves at c relative to all of them in their own frame of reference but it obviously moves at different rates relative to objects that are in motion relative to an observer"

 

You seriously do not see a contradiction there?

If you still can't see it, you are hopeless.

Anyway, I give up on you. Believe whet you want.

[A-wal]

There is no contradiction. The contradiction would be if light were able to move at the same speed relative to objects that are in motion relative to the observer as it does relative to the observer themselves.

 

 

A and B are moving away from each other at 0.5c.

 

0.5c
A<-------------------------------------------------------------------->B

 

 

A's frame of reference.

Light-------1c--------------------------------------------------------------------0.5c---------->
A-------------------------------------------------------------------->B

 

 

NOT this

Light-------1c--------------------------------------------------------------------1c---------->
A-------------------------------------------------------------------->B

 

 

In A's frame the light moves at 0.5c relative to B because the light is moving at 1c relative to A and B is moving away from A at 0.5c.

B is time dilated and length contracted in A's reference frame so to switch to B's frame you have to alter the speed of light relative to B.

This is what brings the speed of light up to c relative to B in B's frame, light always moves at c relative to the observer in their own frame.

If the light moved at 1c relative to B in A's frame then it couldn't possibly be 1c relative to B in B's frame and its speed wouldn't be constant.

 

 

 

Two objects are moving away from each other at 0.882353c in their own frames of reference.

 

0.882353c
A<------------------------------------------------------------------------>B

 

 

From the frame of reference of an observer in between them they're moving away from each other at 1.2c.

 

1.2c
A<------------------------------------X----------------------------------->B

  0.6c                                    0.6c

 

They can't possibly be moving away from each other at the same speed in one frame of reference as they are in another.

Edited January 21, 2017 by A-wal

[A-wal]

Okay there's only so many spades (shovels for USians) that you can hand someone and watch them dig so I'll clarify this properly now.

When an object is in motion relative to an observer it is time dilated and length contracted from the observer's perspective. From the perspective of the object that's in motion relative to the observer it's the other object that's time dilated and length contracted (I'll only use inertial motion). This is how the speed of light can be constant for all inertial observers and it's what prevents any object from reaching the speed of light relative to any observer, because acceleration increases time dilation and length contraction as well as relative velocity.

If only time dilation or only length contraction occurred then it would be a linear progression so that at 0.25c an object would be either 75% of it's proper length or moving through time at 75% of its proper rate from the perspective of the other observer. Because both occur and velocity is distance over time it means that the amount of time dilation and length contraction that actually occurs is the square root of what either would be on their own, so at higher relative velocities the same amount of acceleration cause a greater increase in time dilation and length contraction and therefore a smaller velocity than it does at lower velocities and time dilation and length contraction approach infinity as the speed of light is approached.

This is what leads to the non-linear velocity addition formula from the special theory of relativity. It applies to any object that is in motion relative to an observer. If two objects are moving away from the observer in different directions (in this example in exactly opposite directions) then each is subject to the velocity addition formula with regards to their velocities relative to the observer but NOT their velocities relative to each other from the perspective of the observer. They are time dilated and length contracted relative to each other in their own frames of reference of course so that the velocity addition formula does apply to the other two objects in their own frames

If one {A} is moving away from the other {B} at 0.6c in B's frame then B is moving away from A at 0.6c in A's frame because the relative velocity between any two objects is the same for both of them but they can't be moving away from each other at 0.6c from the perspective of the observer that's in between them. From the perspective of that observer the total amount of time dilation and length contraction that applies to A and B is less than the amount of time dilation and length contraction that applies to them from the frames of reference of A and B. Time dilation and length contraction are already taken into account with regards to A and B's velocity relative to the initial observer so you don't apply it again to their velocity relative to each other in the frame of reference of that observer.

This keeps the speed of light constant relative to every inertial observer in their own frame of reference. It doesn't apply to objects that are in motion in that frame of reference. This is basic common sense because if light is moving a c relative to an inertial observer then in that frame of reference it can't possibly be moving a c relative to an object that's in motion relative to that observer. If A and B are both moving away from the initial observer at 0.6c in opposite directions then the velocity addition formula has already been applied to each one relative to the observer and they're are moving away from at 1.2c in the observer's frame of reference because the velocity addition formula doesn't apply (it's already been done in this frame) but in the frame of reference of either A or B they are moving away from each other at 0.882353c because the velocity addition formula does apply.

Edited February 2, 2017 by A-wal

[billvon]

Let's say you now stand on an intergalactic freeway. You see a truck heading in one direction at 0.6c, and a car heading in the opposite direction at 0.7c. What is the velocity of the truck relative to the car? It is not 1.3c, because nothing can travel faster than c.

This is, of course, untrue.    Group velocities of EM waves can exceed C.  You can see things that, when you do some math, exceed C.  However, no object, particle or information in any of the above cases is moving faster than C - it is just your perception of the event.

[OceanBreeze]

This is, of course, untrue.    Group velocities of EM waves can exceed C.  You can see things that, when you do some math, exceed C.  However, no object, particle or information in any of the above cases is moving faster than C - it is just your perception of the event.

 

 

Oh snap!

 

Could you try a little harder to find something to disagree with?

 

Of course, the passage you quoted is clearly talking about the relative velocity between a truck and a car; two objects and nothing to do with phase velocity or group velocity.

 

I am well aware of phase velocity and it is not a "thing" in the usual sense of the word and as you say it carries no information at a velocity greater than c. I have run experiments using both phase velocity and group velocity in waveguides, many years ago and they do not violate the postulate of special relativity that nothing can have a velocity greater than c.

[OceanBreeze]

Okay there's only so many spades (shovels for USians) that you can hand someone and watch them dig so I'll clarify this properly now.

 

When an object is in motion relative to an observer it is time dilated and length contracted from the observer's perspective. From the perspective of the object that's in motion relative to the observer it's the other object that's time dilated and length contracted (I'll only use inertial motion). This is how the speed of light can be constant for all inertial observers and it's what prevents any object from reaching the speed of light relative to any observer, because acceleration increases time dilation and length contraction as well as relative velocity.

 

If only time dilation or only length contraction occurred then it would be a linear progression so that at 0.25c an object would be either 75% of it's proper length or moving through time at 75% of its proper rate from the perspective of the other observer. Because both occur and velocity is distance over time it means that the amount of time dilation and length contraction that actually occurs is the square root of what either would be on their own, so at higher relative velocities the same amount of acceleration cause a greater increase in time dilation and length contraction and therefore a smaller velocity than it does at lower velocities and time dilation and length contraction approach infinity as the speed of light is approached.

 

This is what leads to the non-linear velocity addition formula from the special theory of relativity. It applies to any object that is in motion relative to an observer. If two objects are moving away from the observer in different directions (in this example in exactly opposite directions) then each is subject to the velocity addition formula with regards to their velocities relative to the observer but NOT their velocities relative to each other from the perspective of the observer. They are time dilated and length contracted relative to each other in their own frames of reference of course so that the velocity addition formula does apply to the other two objects in their own frames

 

If one {A} is moving away from the other {B} at 0.6c in B's frame then B is moving away from A at 0.6c in A's frame because the relative velocity between any two objects is the same for both of them but they can't be moving away from each other at 0.6c from the perspective of the observer that's in between them. From the perspective of that observer the total amount of time dilation and length contraction that applies to A and B is less than the amount of time dilation and length contraction that applies to them from the frames of reference of A and B. Time dilation and length contraction are already taken into account with regards to A and B's velocity relative to the initial observer so you don't apply it again to their velocity relative to each other in the frame of reference of that observer.

 

This keeps the speed of light constant relative to every inertial observer in their own frame of reference. It doesn't apply to objects that are in motion in that frame of reference. This is basic common sense because if light is moving a c relative to an inertial observer then in that frame of reference it can't possibly be moving a c relative to an object that's in motion relative to that observer. If A and B are both moving away from the initial observer at 0.6c in opposite directions then the velocity addition formula has already been applied to each one relative to the observer and they're are moving away from at 1.2c in the observer's frame of reference because the velocity addition formula doesn't apply (it's already been done in this frame) but in the frame of reference of either A or B they are moving away from each other at 0.882353c because the velocity addition formula does apply.

 

 

Yeah, still horribly wrong.

 

You can start by finding references to support all of your assertions in RED.

 

I will just repeat what I wrote above, although I know it has no chance of sinking in to you thick skull:

 

 

1) the rules for adding up relative velocities change in special relativity. In "common-sense" physics (ie. the realm that we're used to deal with), if the bus is moving at speed v and a person in it is moving at speed u relative to the bus (and in the same direction) then the persons speed relative to the ground is just w = u+v.

This is called the Galillean transformation. In the theory of special relativity though, the speed relative to the ground becomes w = (u + v)/(u*v/c*c + 1)

 

(now a Lorenztian transformation) so you can see that even if u=c and v=c then w = c! You can't go faster than c relative to anything! Source here.

 

2) One of the basic postulates of special relativity: The speed of light in a vacuum is the same for all observers drifting through gravity-free space (more precisely: for all inertial observers. In particular, its value its independent of an observer's motion relative to the source of the light. Source here.

 

3) Essentially, then, the Special Theory of Relativity can be boiled down to its two main postulates: firstly, that physical laws have the same mathematical form when expressed in any inertial system (so that all motion, and the forces that result from it, is relative); and secondly that the speed of light is independent of the motion of its source and of the observer, and so it is NOT relative to anything else and will always have the same value when measured by observers moving with constant velocity with respect to each other. Source here

[billvon]

Of course, the passage you quoted is clearly talking about the relative velocity between a truck and a car; two objects and nothing to do with phase velocity or group velocity.

It has quite a lot to do with it.

 

Group velocity can exceed the speed of light because nothing is moving faster than the speed of light; it is only an apparent speed created when you observe more than one photon.  It is not the actual speed of any particle within the system.

 

Closing velocity can exceed the speed of light because nothing is moving faster than the speed of light; it is only an apparent speed created when you observe more than one vehicle.  It is not the actual speed of any vehicle within the system.

 

I am well aware of phase velocity and it is not a "thing" in the usual sense of the word

 

Excellent!  Perhaps you will soon realize that closing speed is not a "thing" either.

[OceanBreeze]

It has quite a lot to do with it.

 

Group velocity can exceed the speed of light because nothing is moving faster than the speed of light; it is only an apparent speed created when you observe more than one photon.  It is not the actual speed of any particle within the system.

 

Closing velocity can exceed the speed of light because nothing is moving faster than the speed of light; it is only an apparent speed created when you observe more than one vehicle.  It is not the actual speed of any vehicle within the system.

 

Excellent!  Perhaps you will soon realize that closing speed is not a "thing" either.

 

In other words, it has NOTHING to do with the two objects, as I said.

 

 

If you have been following the thread, you would know that I have never referred to closing speed as a *velocity* and I have said several times that the rate that a distance either increases or decreases between two objects that are both in motion relative to a central object, can exceed c, but that is not a velocity.

 

For clarity and using A-wal’s example:

 

Each craft is moving relative to the central observer at 60% c in opposite directions.

 

The central observer sees the gap widening at 1.2 c. This is NOT a velocity and therefore does not violate SR which postulates that c is the maximum possible velocity and neither craft is observed as travelling faster than c. A velocity must have both magnitude and direction. A gap widening from a central point does not have one specific direction.

 

Craft 1 cannot observe craft 2 as travelling faster than c, relative to craft 1. And craft 2 cannot observe craft 1 travelling faster than c relative to craft 2.

 

Therefore, neither craft can observe the gap as widening faster than c.

 

Distance:

From the perspective of central observer, the distance between the ships is increasing by 1.2c.

 

Velocity:

From the perspective of either ship, the distance between them and the other ship is increasing by 0.882c. In other words, the relative velocity of the other ship is 0.882c, according to Einstein’s velocity addition formula w = (u + v)/(u*v/c*c + 1).

 

From the perspective of a central observer, the distance between himself and each ship is increasing by 0.6c. In other words, the relative velocity of each ship is 0.6c, referenced to the central observer.

 

Also, from the perspective of central observer, the relative velocity between the two ships is 0.882c, according to Einstein’s velocity addition formula w = (u + v)/(u*v/c*c + 1).

 

All observers must agree on these relative velocities.

 

Finally

 

From the perspective of everyone, light travels at c. as it is NOT relative to anything else and will always have the same value when measured by observers moving with constant velocity with respect to each other. 

 

If you see anything that you disagree with, be sure and let me and Einstein know about it!

 

Now, just for completeness, perhaps you would like to comment on A-wal’s statements?

 

Here they are, quoting directly from his post number 216 in BRIGHT RED:

 

1). If two objects are moving away from the observer in different directions (in this example in exactly opposite directions) then each is subject to the velocity addition formula with regards to their velocities relative to the observer but NOT their velocities relative to each other from the perspective of the observer.

 

He is saying the velocities of the two objects relative to each other from the perspective of the central observer is not subject to Einstein’s velocity addition formula. In other words, just add 0.6c to 0.6c and their relative velocity is 1.2 c.

Do you agree?

 

2). Time dilation and length contraction are already taken into account with regards to A and B's velocity relative to the initial observer so you don't apply it again to their velocity relative to each other in the frame of reference of that observer.

 

This one is a real howler! He is saying that the two objects are not time dilated and length contracted with respect to each other relative to a central observer.! WTF?Makes no sense at all to me.

Do you agree?

 

3). if light is moving a c relative to an inertial observer then in that frame of reference it can't possibly be moving a c relative to an object that's in motion relative to that observer

 

Here he denies the invariance of the speed of light, saying that the speed of light depends on relative motion!

Do you agree?

 

Remember now, A-wal has been passing himself off as the resident expert on Special Relativity on this comical science forum, with the moderators looking on approvingly, so don't step on his toes.