Debate:Relativity-blah-blah

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Stupidity and Ignorance are not synonymous for being wrong!

OK, "Conservapedians" are wrong about almost every topic they handle, except relativity, I am an atheist (ex-Muslim)and a libertarian socialist, but I agree with them on this one, of-course they offer no coherent criticism of relativity, but they are right in saying that serious criticism of relativity is suppressed by the scientific community.

There are many great minds that refused relativity, but unfortunately there voices were silenced by the almost dogmatic fervor of relativity believers, voices such as: Hannes Alfvén (1970 Nobel Prize in Physics), Louis Essen (inventor of the atomic clock), Nicola Tesla (the father of electricity, just google him), Herbert Dingle (President of the British Royal Astronomical Society), Hendrik Lorentz (1902 Nobel Prize in Physics, and the formulator of Lorentz transformation, i.e the basis of Einstein's relativity!), Albert Michelson (1907 Nobel Prize in Physics, and the mind behind the Michelson–Morley experiment).

However, you don't need a great mind to debunk relativity, all you need is a basic understanding of math, and some rationality, and you will reach this simple conclusion; Einstein was wrong, his equations were flawed, beginning with his 1905 papers, and all of his subsequent publication on special relativity. ^{— Unsigned, by: 41.235.139.109 / talk / contribs}

Terrific, Show the math, please. </sarcasm> 02:13, 26 September 2010 (UTC)

(EC) If the BoN is an epistemological anarchist, the BoN's attitude is quite easy to understand, there being in that case a very simple syllogism enabling the necessary conclusion.

1. I don't like relativity.
2. There are no rules in epistemology.
3. Therefore, relativity is wrong. ListenerX^TalkerX 02:17, 26 September 2010 (UTC)

Lol at, with, and with all three of you, respectively. ħuman 05:44, 26 September 2010 (UTC)

• Claims that people with his viewpoint are suppressed, persecuted, and/or silenced - check.
• Resuscitates dead controversy - check.
• Focuses on real or supposed history of an idea (specifically a single originator) rather than evidence regarding it - check.
• Oblivious to more recent evidence regarding a theory; consensus is based on "faith" or "dogma" - check.
• Ignores evidence for consequences of the theory, demanding instead unreasonably direct evidence based on a misunderstanding of the theory. - uncertain.
• Makes no specific point, preferring quote-mining, name-dropping, and "it's obvious" (sometimes including an argument from incredulity) - check.
• Believes that refutation is simple, even though theory is supported by majority of experts in the field - check.

Ladies and Gentlemen, we have a crank. --Quantheory (talk) 06:52, 26 September 2010 (UTC)

I would only respond to the first comment (show me the math), and I will use Einstein's own derivation of Lorentz transformation, published in his 1916 book (Relativity: The Special and General Theory; http://en.wikisource.org/wiki/Relativity:_The_Special_and_General_Theory).

Lorentz transformation is Part I, Section 11 (http://en.wikisource.org/wiki/Relativity:_The_Special_and_General_Theory/Part_I#Section_11_-_The_Lorentz_Transformation).

The derivation itself is in Appendix 1 (http://en.wikisource.org/wiki/Relativity:_The_Special_and_General_Theory/Appendix_I), (please read them before proceeding).

In the derivation Einstein offers two opposite arrangements;

• Arrangement (I)

A light signal which is proceeding along the positive axis of x (to the right) giving the following results:

x = c t (or c = x /t)

x' = c t' (or c = x'/t')

i.e.

x − c t = 0 ..................(1)

x' − c t' = 0 ..................(2)

and

(x' − c t') = λ(x − c t)..........(3)

• Arrangement (II)

If we apply quite similar considerations to light rays which are being transmitted along the negative x-axis (to the left)

x = - c t (or c = - x /t)

x' = - c t' (or c = - x'/t')

i.e.

x + c t = 0

x' + c t' = 0

and

(x' + c t') = μ(x + c t).............(4)

• Notes on the introduction of λ and μ

1) Equation (3) holds true even if λ = 1

2) Equation (4) holds true even if μ = 1

• Restrictions on the values of X, X'

(You can ignore this section if you are bored, it only provides the logic behind uncovering Einstein's blunders, the real blunders are in the next section)

1) Frame k' is moving with a relative speed of (v) compared to frame (K), this speed is along the positive x-axis, i.e. to the right as indicated in fig.2 of section 11

2) Arrangement (I) introduces a light signal moving in the same direction of (v) with an absolute speed (c), while the light signal of arrangement (2) is moving in the opposite direction of (v) with the same absolute speed (c)

3) Accordingly, all equations of arrangement (I) hold true only for positive values of x,x' (because light is moving along positive x-axis), otherwise if we measure the speed of light we will find that: (c = x/t = x'/t')< 0, i.e. c is negative and the light signal would be moving in the opposite direction of (v), and along the positive x-axis in the same time, which is obviously a contradiction

4) Similarly, all equations of arrangement (II) hold true only for negative values of x,x' (because light is moving along the negative x-axis), otherwise if we measure the speed of light we will find that: (c = - x/t = - x'/t')< 0, i.e. c is negative and the light signal would be moving in the direction of (v), and along the negative x-axis in the same time, which is also a contradiction

5) These restrictions are necessary to avoid contradictions, but we will find that Einstein was not aware of them when he proceeded to the next step

Einstein's next step was to combine these two arrangements into on equation:

• Combining Arrangements (I) and (II)

We have so far

(x' − c t') = λ(x − c t) ................(3)

(x' + c t') = μ(x + c t) ................(4)

but each of these equations is restricted to a separate arrangement, with restricted values of x,x', He however choose to add or subtract the equations ignoring the hidden contradictions, giving the following equations:

after also substituting

a = (λ + μ) / 2

b = (λ - μ) / 2

we get

x' = a x - b c t ..........(5a)

c t' = a c t - b x ............(5b)

• Notes on combining arrangements (I), (II)

1) Now that Einstein has combined these two arrangements, treating them as parts of a single system, the contradictions will be much more obvious, as in his steps to reach equations (5a) and (5b), he used the following equations, and now he assumes that all of them are true concurrently:

x = c t (or c = x /t)...............(fucked up equation 1)

x' = c t' (or c = x'/t')..............(fucked up equation 2)

and

x = - c t (or c = - x /t)............(fucked up equation 3)

x' = - c t' (or c = - x'/t')...........(fucked up equation 4)

Substituting c t = x from (fucked up equation 1) in (fucked up equation 3) we get:

x = - x

and accordingly

x' = - x'

If you are not surprised by now, then you understand nothing about math, these equations means:

if x = 1

then 1 = -1

if x = 2

then 2 = -2

Which is why I call them fucked up equations, the only condition when these equations hold true is when x = x' = 0, for all other values of x,x' you have nothing but nonsense.

2) If you think that you are smart and will say, that these equations are wrong because these equations belong to different arrangements, I will tell you sorry, it wasn't me who came up with the whole thing, it wasn't me who combined the two separate arrangements, it was your divine Einstein who decided to put the two arrangements in the same equation together (equations 5a and 5b)

3) A variation on the fucked up equations is the following:

c = - c

t = - t

t' = - t'

which all holds true only if c, t , t' = zero, now you have no speed of light, no time variation, we have nothing at all.

4) Ignoring all of these blunders let's see how Einstein chooses to not see them and proceed in his next step, which is more fucked up, because he tries to evaluate his constants at the only working conditions, (i.e. when any of x,x',t,t' =0)

• Einstein's evaluation

so far we have:

x' = a x - b c t ..........(5a)

c t' = a c t - b x ............(5b)

I actually suspects that Einstein knew that his equations is fucked up, because the following is just stupid.

He puts x'=0 (at the origin of k') in equation (5a) giving:

0 = a x - b c t

i.e.

x = b c t / a ...............(fucked up equation 5)

and he magically assumes that x/t = v (which could be true but not with his fucked up equations), then he gets

v = b c / a ..................(6)

• Notes on Einstein's evaluation

1) He set x' = 0 alone, ignoring the corresponding values of the other variables (x,t,t',c), but if he thought carefully about it he would have found that according to his preliminary equations (the fucked up ones) :

c = x'/t'= - x'/t'= zero/t'= -(zero)/t' = 0

i.e.

if x'= 0 , then c = zero , but of-course light could never propagate at a speed of zero, so this what would this mean?, I don't know, you tell me, but let's continue

substituting c=0 in (fucked up equation 5)

x = b c t / a = b * 0 * t / a = 0 / a = 0

but if x = 0 and according to (fucked up equation 1)

x = c t

i.e. t = x/c = 0/c = 0

or t = x/c = 0/0 (you tell me what this means)

and if c = 0, then substituting it in equation (6) we have

v = b c/ a= b * 0/ a = 0 / a = zero

then if v = zero, the moving frame is not moving at all

2) To derive equation (6) Einstein assumed that v = x/t forgetting the fucked up equation 1)

c = x/t

does this means that c = v = x/t, i.e. c = v, a new revelation the moving frame is moving with the speed of light, though we have already established that it isn't moving at all

• I think this is enough :)

I would assume that the Nobel Committee is hard at work on your Prize. ħuman 01:50, 27 September 2010 (UTC)

I'm bored enough to argue this. Here goes.

"it was your divine Einstein" First off, you can stop saying crap like that. Einstein was wrong a lot, most notably about quantum mechanics. He was a smart man but he is only "worshiped" in pop-sci. Moreover, given that he was virtually unknown before 1905, I highly doubt that physicists of his era would have considered him "divine".

Anyway, on to the math. In this particular case, the "Simple" derivation is just an early re-derivation, thrown into the appendix to help persuade readers that his theory really does give the Lorentz transformation. It should not surprise you if parts of the derivation are less than ideal for the modern lay audience. If you understand linear algebra, there is a more recent version that is much clearer. In that reference, equations 24/25 show the class of transformations consistent with a basic set of space-time symmetries. Galilean transformations are those that take the limit where the constant "a" is infinitely large (whether positive or negative is irrelevant; the equation will have the same limit in either case). The Lorentz transformation simply takes a=-c².

As for the "problems" you've found with Einstein's description, you are simply missing a step he glossed over. You notice that he says "Those space-time points (events) which satisfy (1) must also satisfy (2)." and then "[Equation (3)] is fulfilled in general". This marks a change between equations (1) and (2), which describe a specific set of points (on a light ray), and equation (3), which describes the general class of transformation that also gives the correct behavior in the specific cases of x=ct and x'=ct'. As a result, equations (1) and (2) (and the alternate versions describing a light ray moving in the other direction) cease to apply after equations (3) and (4); they describe only a specific set of points (x,t) and (x',t') that Einstein wanted to momentarily point out.

To put it another way, Einstein could have said "We are looking for a linear transformation between coordinates, and Eq (3) is the only one that gives the answers we want on the lines (1) and (2) (and the same with (4) and the left-moving versions)." (1) and (2) describe interesting sets of points in space-time but are not equations describing something deep about the coordinates themselves, as equations (3) and (4) are intended to be.

Similarly, x/t = v does hold for the points where x'=0. x'=0 is just the location of the train. In the platform coordinates, that point does move at velocity v, so the train's position is at x=vt. You seem unable to tell when Einstein is using descriptions of specific sets of points (such as the points at the train's origin or on a particular light beam) and when he is describing the general transformations that apply to all points in space-time.

I submit that the biggest problem here is that you are unfamiliar with the usual style of physics derivations (and even less familiar with the style in 1905; yes, mathematical proofs do change in style and notation quite a lot with time), as well as with common derivation techniques, and the background knowledge which Einstein assumes his readers have. Thus you are oblivious to the contextual clues that signify these changes in generality, as well as to the reasons why Einstein chooses to take a particular path. I would say the same to anyone who communicated this tripe to you in the first place. If you want to really understand something, a modern course or textbook is a better place to look. Then you can be more certain of whether the problem you see is a problem with the theory, or just your inability to understand the appendix of a 1905 proposal written for people from a totally different background.

In any case, for someone who's sufficiently mathematically literate and knows what the goal here is (finding a set of linear transformations that preserve certain lines), it's actually quite easy to reproduce this proof; it hardly depends on "Einstein's genius". Besides which, the Lorentz transformations pre-dated him anyway. --Quantheory (talk) 03:09, 27 September 2010 (UTC)

Firstly I want to respond to your "recent version" of the derivation, but please try to read my response carefully, without judging it with bias.

Though I have only read till step (2) and equation (5), I claim that this derivation is also wrong, because it commits the same mistakes as Einstein, and I can prove it as follows:

• step (I): Excluding the Galilean transformation

In equation (2) of the derivation we have:

x' = A x + B t ............(2)

where A and B are functions of v, and this equation is an expression of a new transformation (i.e. Lorentz transformation), assuming that the Galilean transformation is not adequate to represent reality (which in this case should be x'= x - v t).

i.e.

A = f1(v)

B = f2(v)

and

x' = f1(v) * x + f2(v) * t ............(2)

• Step (2) Reintroducing the Galilean transformation

However in the step (2) the author reintroduces the Galilean transformation, when he assumes that x = v t when x'=0, because his has used the following logic:

x' = x - v t

but since x'= 0 we get

0 = x - v t

and

x = v t

of course this is a contradiction because according to step (1), the Galilean transformation is excluded from calculations, and we can not use it to calculate the values of x and x', so that when we have x' = 0 we should only get

0 = A x + B t

not

0 = x - v t

because the last equation holds true only if we are using the Galilean transformation in every calculation, but the author ignored this, and used both equations together as follows:

x = v t (only true if you think that the Galilean transformation are true, which is not the case)

and

x = - B t / A

concluding that

B = - v A

and reaching this equation

x' = A (x - v t)............(5)

Again this equation is wrong because it assumes that we can use the Galilean transformation and the Lorentz transformation together as valid representations of reality, but the truth is you can choose only one of them.

Of course Einstein made the same mistake when he substituted v = x / t at x' = 0

• step (6) Introducing the speed of light

I only skimmed all steps after step (2), in particular searching for (c), then I found it at equation (26)

a = - c^2 ................(26)

I can't buy the justification for limiting (a) at (-c^2), or at least for giving it a negative sign, was this "revealed" to the author somehow? maybe Jesus visited him in his sleep and told him so.

• Notes on your defense of Einstein's derivation

1) I don't get you, first you say that Einstein has many mistakes, and it's normal to find inconsistency in his work, but then you go defending him, please be clear

2) You are accusing me glossing over steps and of not understanding the meaning behind the symbols, but then you say that we can change the meaning of the symbols along the same derivation, deactivating the validity of the preliminary equations without creating contradictions.

3) You have performed a miracle when you said: "Einstein wanted to momentarily point out" "Einstein could have said We are looking for a linear transformation between coordinates" "Einstein assumes his readers have" "the reasons why Einstein chooses to take a particular path" you proved that you can read the minds of dead people :)

4) you are assuming that I am misguide and/or misled to believe things which are not true, because I "can't" understand the style and/or math of physics derivations, and don't use the text books, but the truth is as follows:

I am an electrical engineer (studied in a 5 years engineering school)

I took 2 years of science education in high school

I studied physics for 4 years (in school and university)

I studied math for 5 years

I studied geometry for 3 years

I have plenty of books and textbooks physics and math

I was using Einstein's own book to refute his derivation not a random book

I didn't copy or reproduce my refutation, it was my own, according to my understanding

I don't take things on faith, I am Egyptian, I live in Cairo, and though at least 99% of Egyptians are either Muslim or Christian, I am an an atheist (which could get me killed in our society)

I am writing this response because I enjoy such discussions, and because I care about the truth, and concerning Einstein, I really don't care whether Einstein was a fraud or the second coming of Jesus, I only care about whether his math was right or not

• Detailed rebuttal of your defense:

1) you alluded to this phrase "Those space-time points (events) which satisfy (1) must also satisfy (2)", let's examine what this means, but first let's clarify the meaning of our symbols

Einstein used the symbol (c) is the absolute (positive) value of the speed of light (i.e. c = 299,792,458 m/s according to the best knowledge of humanity), the proof for this is that this symbol exists in his last calculation of Lorentz factor representing the same meaning

i.e. in Lorentz factor

1/sqrt(1-(v/c)^2)

c = 299,792,458 m/s and is always positive, and this is the same (c) he uses in his preliminary equation, because you can't change the meaning of symbols along the same derivation

so when he says that x = c t and x' = c t', and since t can not be negative, then x, x' are restricted to positive values, other wise the symbol (c) will acquire a negative sign, changing the meaning of the symbol

accordingly when he says that x = - c t and x = - c t', and since t can not be negative, then x, x' are restricted to negative values, other wise the symbol (c) will acquire a negative sign, changing the meaning of the symbol

The same restrictions applies for equations (3) and (4), the phrase "Equation (3)] is fulfilled in general" is wrong, and it won't be true just because Einstein said it, it's not fulfilled in general because any solution must preserve the positive value of (c), and this won't be true unless the solution also fulfills equations (1) and (2).

Again what you are trying to do is change the meaning of the symbols x,x' though the derivation, sorry this is not mathematically coherent, equations 1,2,3,4 use the same symbols, so they are interchangeable, i.e. any given value of x,x' can be substituted in any of them, BECAUSE THEY USE THE SAME SYMBOLS, OTHERWISE YOU WILL BE CHANGING THE MEANING OF THE SYMBOLS IN THE SAME DERIVATION :)

2) you said

"1) and (2) describe interesting sets of points in space-time but are not equations describing something deep about the coordinates themselves, as equations (3) and (4) are intended to be"

But if equations 1,2 are different from equations 3,4, and describe different things, WHY ARE THEY USING THE SAME SYMBOLS?

If they meant different things then the right mathematical procedure is to use different symbols for different things, so please do not try to force your personal understanding, or may I say interpretation of the divine texts of relativity on me.

The truth is Einstein didn't mean what you say, end even if he did, he was wrong in not changing the symbols

3) Here is what really went wrong, Einstein have set up two different arrangements, and concluded equations 3,4 from each, here we are really talking about two different set of events, distances, locations, time intervals, and measurements.

However, the coherent mathematical procedure was to use a unique set of symbols for arrangement (I) (say x1, x1', and t1, t1'), and another unique set for arrangement (I) ((say x2, x2', and t2, t2')

Of-course Einstein didn't do that, because these equations were "divinely revealed" to him.

4) you wrote:

"Similarly, x/t = v does hold for the points where x'=0"

This is the major blunder in every derivation of the Lorentz transformation, i.e. reintroducing the Galilean transformation, but considering them invalid at the same time, I already explained this previously so I don't have to repeat myself.

(by the way this is why I said that Einstein "magically assumed that x/t = v)

• Notes on the whole discussion, and relativity in general

Here is what's wrong with all derivations of Lorentz transformation

1) using the same symbols for different variables

2) changing the meaning of the symbols along the derivation

3) reintroducing the Galilean transformation to evaluate unknown variables

4) ignoring the corresponding values of other variables when evaluating an unknown variable, leading to incoherent evaluations

the mathematical derivation of relativity refutes the theory every time, however there are many other ways to refute the theory

for example the reciprocity of time dilation and length contraction (at least for special relativity)

i.e special relativity leads to:

x = x' / γ and t = γ t'

but also leads to

x' = x / γ and t' = γ t

(where γ is the Lorentz factor)

solving these equations together leads to γ = 1, and restores the Galilean transformation, strangely science have taken a wrong road and decided to curve space-time, i.e. curving the coordinates, or the inertial frames, though that they don't even exist in reality, they are only constructions to measure time and distances

This reminds of christian theologians trying to re-interpret the trinity :)

"Firstly I want to respond to your "recent version" of the derivation, but please try to read my response carefully, without judging it with bias." I wonder if you extend others the same courtesy, or if you just like to think that you do. I wonder, does it hamper your judgment to feel "superior" to all those people who you think are "fooled" by relativity? I wouldn't know, but if I were you I would make sure that didn't stop me from listening to valid support for the theory.

"I have only read till step (2) and equation (5)" That's a shame. The derivation I linked would probably appear more mathematically rigorous and clear to you. Einstein's derivation assumes that you have some background understanding, for example that the transformation from x and t to x' and t' must be linear.

"Excluding the Galilean transformation" No. He is providing a general transformation, which could be the Galilean transformation, or could be the Lorentz transformation. Neither of those specific transformations appear in the derivation at all before Equation 24/25.

"he assumes that x = v t when x'=0" No. When he says that one coordinate system moves past the other at speed "v", that is defining the variable v as referring to the speed at which the origin of one frame moves with respect to the origin of the other frame. This is not a use of the Galilean transformation, even though using the Galilean transformation (or the Lorentz transformation!) gives you the same answer. This is simply a property of the system as he set it up in the original premises. You made the same mistake the first time. He is saying that for the specific space-time points where x'=0, x = vt, whereas for other spacetime points (in general), x' = Ax-Bt.

As an analogy, let's say that you know that the voltage across a resistor varies as V = A sin(ft) + B cos(ft), and you also know that at time t=0, V=0. Then you know that B=0 and can simplify the original equation to say that V=A sin(ft). None of these equations contradict each other in the proper context, even though one says V=0 and one says V=A sin(ft)! In fact, you could make this explicit by saying that voltage is a function of t, so the equations would be V(t) = A sin(ft)+B cos(ft), V(0) = 0, therefore V=A sin(ft).

What's being done in this derivation is the same thing.

"I can't buy the justification for limiting (a) at (-c^2)" That's because he didn't give one. The point of that paper was to derive which transformations were possible, and it simply noted that the Lorentz transformation was a special case of the one they derived in general. If you want to know the justification, it's that a=-c^2 gives a constant speed of light between reference frames, which is something predicted by Maxwell's equations, not falsified by Michelson-Morley, and now special relativity has successfully predicted quite a lot of things (atomic clock changes, energies and lifetimes of particles in cosmic rays and accelerators, mechanics of astronomical systems, and now it's it's an indispensable part of Quantum Electro-Dynamics, which is a theory that gives some ridiculously precise predictions). You can shove this faith rhetoric somewhere obscene; this stuff is experimentally verified.

"I don't get you, first you say that Einstein has many mistakes, and it's normal to find inconsistency in his work, but then you go defending him" What an unbelievably stupid statement. Saying that someone has made many mistakes is not inconsistent with saying they have said some smart things too. Everyone makes stupid mistakes from time to time. You, me, Einstein, Darwin, the pope, EVERYONE. But some people say smart things too.

"you say that we can change the meaning of the symbols along the same derivation" If and only if everyone recognizes the shift in meaning in the same way, and if you don't combine equations with different symbol meanings. In my above example, if you combine the equations "V=0" and "V =A sin(ft)", without noticing that the condition "t=0" applies only to the first one, you might falsely conclude that A = 0 and that V=0 at all times. The derivation relies on people keeping track of the various conditions placed on these equations. If you aren't willing to do that, then I guess the derivation is useless to you. Oh well.

"you proved that you can read the minds of dead people" No, I just can comprehend his proof, and I can read what he said, and I can guess his intention from that. If I said "I'm really hungry, and I'm going to go get a sandwich." you would be pretty certain that I was going to go eat a sandwich. And yet I haven't told you that I'm going to eat anything. You're a mind-reader!

"I am an electrical engineer" Congratulations. I hope that's going well for you, but that doesn't raise my opinion of your ability to understand simple derivations. See, I know several people who got engineering degrees without that skill, and who would admit as much. One or two even got the same degree I did (engineering physics). You seem to be another for my list. I don't mean to rain on your parade, but lots of engineers make it through college by learning how to look up the right equations and plug numbers into them, right up through differential equations, and then doing a lot of cramming to memorize specific techniques. It's difficult to follow many proofs, and they don't focus on them in many engineering/science courses. Not to mention that theoretical physicists, chemists, and mathematicians all have developed slightly different conventions (from each other and from engineers who work in electrical engineering, optics, or signal processing).

"I am an an atheist (which could get me killed in our society)" You have my sympathy. But it's irrelevant to this conversation. You can be an atheist and still make dumb mistakes (like everyone does).

"I really don't care whether Einstein was a fraud or the second coming of Jesus" Good, because neither is reasonable. I don't think you can argue that Einstein was a fraud if he made honest mistakes, nor is it reasonable to argue that his work on Brownian motion or the photoelectric effect was fraudulent even if his work on special relativity was. We're not discussing Einstein's character, we are discussing special relativity.

"since t can not be negative" Wrong. You can have an origin in time. When they launch the space shuttle, they announce "T minus 30 seconds". Before the launch is negative time, and after the launch is positive time. t=0 is just the arbitrary origin with respect to which you measure something.

"any given value of x,x' can be substituted in any of them, BECAUSE THEY USE THE SAME SYMBOLS, OTHERWISE YOU WILL BE CHANGING THE MEANING OF THE SYMBOLS IN THE SAME DERIVATION" Because you're being so bone-headed, I'll give another example about this same point. Let's say that we have a line in a Cartesian coordinate system. We know that when x = 2, the y coordinate of the line is y = 4. When x = 0, y = 10. Then you can conclude that the equation describing the line is y = -3x + 10. Clearly the meaning of the symbols "x" and "y" has changed though, modified by the words and context. If you say, "x = 2, and x = 0, therefore 0 = 2 and it's a contradiction so you are wrong!", then you are not finding a contradiction, you're just making a dumb mistake because you don't understand what I'm saying.

"so please do not try to force your personal understanding, or may I say interpretation of the divine texts of relativity on me." You may not say that unless you want to be dishonest. Shut up about this "relativity is faith" bit. Even if you did disprove relativity, it does not automatically follow that the people who believed that it was true took it "on faith". Who is it that was lecturing me about reading minds?

"The truth is Einstein didn't mean what you say, end even if he did, he was wrong in not changing the symbols" I agree that it makes it less clear that he doesn't change symbols. It is possible to make things more clear by, for example, saying x'=A x(x',t')+B t(x',t'), thus making the coordinates in one system functions of coordinates in the other. But, for various reasons, that's not standard practice when doing these coordinate conversions. See here for a modern example. It makes sense to follow strange conventions if your peers will understand your intent.

"Einstein have set up two different arrangements, and concluded equations 3,4 from each" No, he has one arrangement, and he then proceeds to note two things about that arrangement. Equation 3 is one constraint on how the transformation can work, and Equation 4 is another such constraint. See my two points in the example above. They are two specific points that constrain the position and slope of one general line.

"these equations were "divinely revealed" to him" I doubt that. Einstein didn't believe in a personal God or in divine revelation, much like you.

"1) using the same symbols for different variables

2) changing the meaning of the symbols along the derivation"

Those are done in a way that's standard and easily recognized by those who are used to it.

"3) reintroducing the Galilean transformation to evaluate unknown variables"

Happens only in your head. "x = v t" at x'=0 is the definition of velocity. If it was not true, then the system would not be the one we're talking about (where one frame moves past another at constant speed).

"4) ignoring the corresponding values of other variables when evaluating an unknown variable, leading to incoherent evaluations"

If you understood the difference between "on the light ray, x = c t" and "in general, x and t are independent", you wouldn't say this.

"x = x' / γ and t = γ t'

but also leads to

x' = x / γ and t' = γ t"

These are not the original transforms. In that truly naive form, they only work for converting lengths or times from the rest frame to a different frame (but not from a frame in which the clock or ruler are moving). Since x/t and x'/t' cannot both be the rest frame, the first and second sets of equations cannot hold for the same object.

There are much more interesting paradoxes in relativity. They have been solved by recognizing that rigid bodies cannot exist in special relativity (a shock-wave can only travel through a material at less than the speed of light, which forces it to compress or expand in some circumstances).

"curving the coordinates, or the inertial frames, though that they don't even exist in reality, they are only constructions to measure time and distances" It's not much more remarkable than using spherical or cylindrical coordinates instead of Cartesian. I don't know what your point was. --Quantheory (talk) 06:16, 28 September 2010 (UTC)

Edit button for sanity

My allusions to Einstein's divinity, relativity as faith or religion, revelations or mind reading was not meant to be taken seriously, that was "humor", still I apologize if my style of writing is somewhat aggressive, and for my occasionally abrasive sense of humor (or lack of it because I couldn't convey my humor clearly), may be it's due to the cultural differences between our societies, or may be I was just in a bad mood, but it was only humor just like this page "http://uncyclopedia.wikia.com/wiki/Cult_of_Relativity", which was probably written by someone who shares my views.

My humor was addressed to the ideas and the views, I didn't mean to belittle you or the anyone sharing your views, because I respect the persons behind these ideas, in spite of our differences.

I admit though that I sometimes exaggerate while trying to lay out my views, but I didn't intend at all to sound "superior", or to belittle the opposing views, so let me be clear, I mentioned my qualifications to demonstrate that I at least have a basic understating of physics and math, I mentioned my atheism amid a "throat-cutting faith dominant" society to demonstrate that I don't rely on blind faith to formulate my views, and not to hint that I am superior, so I apologize again if I sounded a bit demeaning, or irrelevant, and I assure you my exaggerations don't stand in my way to examine the opposite views.

I also thank you for your responses, which shows that you have taken the effort to at least skim through my posts, If not examining them thoroughly, i.e. you are not dismissing my claims though you think that I am a crank t as you wrote in your first comment :)

That being said, I sadly hold my ground, your last response wasn't convincing to me, it seems that though I try to express my views as clear and simple as possible, there are still several arguments that failed to come through, and you either misunderstood my arguments completely, or looking at things for a completely different point of view.

So next time I will try to focus on the math itself, making things as simple as they could, and explaining the logic behind every arguments in mathematical terms, not in logical terms using words.

But first allow my to pose some questions:

What are your reasons for being interested in answering my posts - aside from boredom - ?

Do you think that relativity is really 100% true and can't be proven wrong?

Do you think or believe that relativity can't be wrong just because it's dominant in the scientific community?

Do you think or believe that relativity can't be wrong just because it has accurate predictions?

Why do you think I am interested in debunking relativity, or in posting here or anywhere about the subject, do you really think that I am a crank or a crackpot?

Why do you think I decided to post a comment on this article, and in rational-wiki from all sights on the web?

What do you think where my views on Einstein and relativity before adhering to my current view?

Of-course I am not asking you to read my mind before answering the questions about me and my views, but I want you to think about the reasons why people like me hold such views, and about the consequences if we were true, however, If you don't feel like answering my questions, please respond accordingly and I will post my next rebuttal afterwards. --Ahmadgad (talk) 21:56, 28 September 2010 (UTC)

Sorry, but I am bored, so I would love to see you posting with your answer a mathematical, logical or geometrical proof confirming that (x = v t) when (x' = 0), and that ( x = v t) is false for any other value of ( x' ), without using the Galilean transformation, and without using the Lorentz transformation (as you can't use the Lorentz transformation to derive the Lorentz transformation), I really love to see you try :) --Ahmadgad (talk) 00:08, 29 September 2010 (UTC)

I am an electrical engineer... This fellow is a textbook example of the Salem hypothesis. ListenerX^TalkerX 03:41, 29 September 2010 (UTC)

In case you haven't notice, I am an atheist, however, I am an atheist and a creationist in the same time, and I think that the Universe was created when i sneezed for the first time! yes the Universe was sneezed out of my nose :)

So the fact that I studied electrical engineering has nothing to do with my ability to sneeze multi-verses,I just mentioned it to demonstrate that I can at least grasp the basics of math and physics, after all you don't math and physics if you can sneeze universes! --Ahmadgad (talk) 04:08, 29 September 2010 (UTC)

My answers:

1. don't care
2. no
3. no
4. no
5. I have no idea, and yes
6. you got kicked out of all the theoretical physics sites?
7. probably equally lame

So there you go, Mr. "electrical engineer". ħuman 04:19, 29 September 2010 (UTC)

My answers:

1. That's pretty much it. I write bits of responses while doing other things, waiting around...
2. Um, I think that anything that's true "can't be proven wrong". If you're asking me whether I'm 100% confident in relativity, I'd say no, but I'm pretty damn confident. How confident are you in Newton's third law?
3. No, that's stupid.
4. Wrong theories can make accurate predictions, but the more they make, the less wrong they are likely to be. I don't think you can dismiss a large body of successful predictions just because a theory makes no sense to you. You have to be able to explain why all that evidence doesn't count under your objections.
5. Yes, I do consider you a crank. I'm not sure that I really care why you post here; there are many possible explanations, all of which lead to the same behavior.
6. I dunno. You like us?
7. I don't care.

As for the x=vt thing, that comes from the definition of velocity. When I say "the train is going by with constant velocity v", and assuming that my time origin is the time when it passes, then I mean that the position of the train is $x_{train}=vt$. It isn't "derived" from anything, it's just what "the train is going by at speed v" means. And by definition, in the train's reference frame, the train is at the origin ($x'_{train}=0$). But of course that only applies to the position of the train. The position of a bird flying around me is not $x_{bird}=vt$, and in the reference frame of the train its position is not $x_{bird}=0$. Using the condition that $x=vt$ if and only if $x'=0$ is thus an appropriate constraint on the relationship between x and x'. Whatever the correct transform is, it has to give the correct position of the train.

"I am an atheist and a creationist in the same time" Don't laugh; it happens. Besides which, there are engineers (and "engineers") who believe in other insane things. --Quantheory (talk) 05:30, 29 September 2010 (UTC)

(If you don't have a lot of time skip to the section titled (What went wrong?), if you are bored and have some time then read from the start, but please read the section under (what went wrong?) carefully, sorry for being so lengthy in my responses).

"you got kicked out of all the theoretical physics sites? ", "You like us?", that was actually funny, I smiled, however the reason why I posted here is because I am searching for someone to have a rational discussion with, of-course about relativity, and though I have never posted in any physics site before, I am pretty sure that if I tried to, no one would take me seriously, and the chance for someone to examine my claims would be very small, and I really like RationalWiki :)

In addition, I have reached the conclusion that most modern physicists never question their positions, so it would be useless to approach them about the subject, just watch this lecture titled "introduction to relativity" from Yale university "http://www.youtube.com/watch?v=pHfFSQ6pLGU", and you will understand why, here the lecturer presents his views as "facts", he is not asserting that "extraordinary claims requires extraordinary evidence", he is sending an opposite message to his students "believe what the scientific community tells you no matter how illogical or incomplete it seems".

I say this is because he produces a wrong derivation for the Lorentz transformation, and I am pretty sure that you would agree with me on this, he starts his derivation with these two equations:

x' = (x - v t ) γ

x = (x' + v t') γ

not with

x' = A x + B t (as provided in the link you have given me)

In other words, he doesn't give that give any justification for considering ( A = γ ), ( B = - γ v ), or ( B = - v A ), nor for using the same constant γ, for the reverse transformation, you can watch the derivation starting from minute 49 and judge for your self.

You can guess that I think that this is the same as introducing (v = x / t) to conclude the same result ( B = - v a ), in both your linked derivation, and in Einstein simple derivation, and that I think that assuming (v = x / t) when (x' = 0), is as wrong as assuming that (B = - v A ) directly, but this doesn't cancel my obligation to demonstrate why this wrong, so I am going to try, but I will first comment on your last response.

I want to be clear, I don't deny at all that (v = x / t) at (x' = 0), I am only saying that it is wrong to insert it in the derivation, it is only true if the Galilean transformation is true, and if the Galilean transformation is true then the Lorentz transformation is meaningless.

"the train is going by with constant velocity v", there are no trains in the derivation written by Victor Yakovenko (the one you linked), we only have systems of coordinates , and you are forgetting that Einstein also said "we can imagine the train traveling with the velocity v to be continued across the whole of space", i.e. his train is a representation of the x' axis, he also said "For the origin of K ' we have permanently x ' = 0", "If we call v the velocity with which the origin of K ' is moving relative to K", so let's forget about the trains, and focus on the coordinates and there relations to each others, because I think this might be one of the reasons for the misunderstanding we have.

You wrote "and assuming that my time origin is the time when it passes, then I mean that the position of the train is xtrain = v t", but I don't get what you mean, what do you mean by your time origin, and does "passes" means passing your time origin.

"it's just what "the train is going by at speed v" means", no it is not, what we have is:

- Frame k' (or O' in the linked derivation), with relative speed of (v) in comparison to frame K (or O in the linked derivation),

- Axis x' from frame k', moving with a speed of (v) relative to to the axis x of frame k

- You can even say that we have the train (implying the axis x'), moving relative to the embankment (implying the axis x) with a speed of (v)

All of this is different from saying "the velocity with which the origin of K ' is moving relative to K", because here you are talking about the relative velocity between a point (origin of k') relative to a complete set of space-time coordinates (K) (which reduces to the line represented by the x axis), you are not talking about the relative velocity between two frames (K, K'), or two lines (axis x' and axis x, or a train and an embankment).

(The next paragraph might sound very stupid, but please bear with me and pretend that you are talking to a child, and try to articulate your response accordingly).

If we are going to talk about the speed of the origin of K', then I think we should only talk about the velocity with which the (origin of K') is moving relative to (the origin of K), which is not a given, but if you insist that you can deduce that (v = x /t) at (x'=0), from "The reference frame (K') moves relative to (K) with velocity v in along the x axis", then what is exactly is stopping you from saying that (v = x / t), at (x' = 1, 2, 3,.......etc.).

"The position of a bird flying around me is not xbird = vt", there are no birds in the derivations, we only have coordinates and variables.

Now let me write down somethings which I think is true:

v = x / t at x' = 0

v = (x - 1)/t at x' = 1

v = (x - 2)/t at x' = 2

v = (x - 3)/t at x' = 3

I think you got the pattern, now I have another question, do you think this is true or not?, and why? --Ahmadgad (talk) 23:29, 29 September 2010 (UTC)

Why should I care about some random physics lecture? An introduction to relativity is probably not going to contain a thorough derivation, but only a sketch of a proof, because more people will care about how to use relativity than about the complete history (and time in class is limited). Outside of mathematics courses, I rarely see rigorous derivations of anything in lectures; interested students are supposed to look it up or fill it in on their own time. You may as well say that Maxwell's equations are wrong because some introduction to electrodynamics course does not connect them rigorously to Coulumb's law.

In any case, regarding the remaining points:

What I mean by "time origin" is simply the time t=0. You can arbitrarily declare that to be any time ("Right now is t=0") but for convenience we take t=0 and t'=0 to be the moment at which the origin of one frame passes the origin of the other frame (the time at which x=0 and x'=0 refer to the same point). Notably, t=0 does not imply t'=0 at any other position unless you assume the Galilean transformation. This is related to the difficulty of synchronizing distant clocks.

You are correct that, from the perspective of K, every point in K' moves with constant velocity v. This is not a result of the Galilean transformation, but rather it's what we mean when we say that one frame moves with constant velocity. Earlier I talked only about the origin of each frame because I thought it would be simpler, but everything which is stationary in K' moves at the same velocity with respect to K. However, your other equations do not follow.

To say that a point moves at constant velocity is to say that dx/dt=v. So a given stationary point in K' moves like this in K: x = vt + C, with C a constant over time. For the point x' = 0, we know that x=0 when t=0 (because we declared t=0 to be the moment where they pass). However, for x'=1, we don't know the position at t=0. You assume that when t=0, the point x'=1 is the same as x=1. But that's begging the question; you have to assume that there is no length contraction for that to be true. If any transformation other than the Galilean transformation is true, x=1, t=0, is not the same point as x'=1, t'=0. Thus, while you can say that the position x=vt is the same as x'=0, you can't say that x=vt+1 is the same as x'=1, without specifying a transformation. Instead you can only say that x=vt+C at x'=1 for some constant C (capitalized to distinguish it from the speed of light). --Quantheory (talk) 02:54, 30 September 2010 (UTC)

What went wrong?

I am now confused about whether to write down my articulation of what we can't insert (v = x / t) or not writing it, because it would be very hard without demonstrative drawings, so before deciding I just want to allude to another consistency in Einsteins derivation.

Einstein reached these two equations (which are also wrong in my opinion):

$x\prime =ax-bct............(5a)$

c t' = a c t - b x ..............(5b)

I think you believe that these two equations holds true simultaneously, so let's see what's wrong in setting x' = 0, because according to my limited understanding, when Einstein says (For the origin of K' we have permanently x ' = 0), and since at the origin of K' is denoted by (0,0,0,0), i.e. at the origin of k', we have x'=y'=z'=t'=0

So let's substitute x' = 0, and t' = 0, for equation (5a) we get:

0 = a x - b c t then x = b c t / a ................. (w1)

but for equation (5b) we get

c * 0 = a c t - b x

0 = a c t - b x

b x = a c t then x = a c t/ b .................. (w2)

now we have:

x = b c t / a ................. (w1)

x = a c t / b ................. (w2)

So if you insist that at the origin of k', were have (x' = 0), we also have (v = x / t), let's substitute this into w1, w2:

v = b c/ a from w1

v = a c/ b from w2

It's obvious that we are talking about the same (v), OK, so you can't tell that we changed the meaning of the symbols, and now we definitely have:

v = b c / a = a c / b .........(w3)

i.e.

b/a = a/b

From which we can conclude

a = b

and

b/a = a/b = 1

Substituting this in (w3)

v =b c/a = a c/ b = 1 * c = 1 * c = c

Now we have (v = c), so what do you think about this? perhaps you may conclude that:

-My evaluation is wrong, check again and again, no, it's true

-Equations (5a) and (5b) are wrong, and I will tell you, yes, Einstein was wrong but you just can't grasp that

-(v = x /t) at (x' = 0) is false, and I will tell you, yes, because this is true only if you are using the Galilean transformation (which is always correct by the way), but it is false if you are going to use any different transformation.

-(v = c) is true, and I will tell you, really!!!?

-I am an alien who sneezed the universe out of his nose, and I am manipulating your brain!--Ahmadgad (talk) 23:31, 29 September 2010 (UTC)

I don't think that I need to refute the other derivation (the derivation you linked, authored by Victor Yakovenko), as it doesn't give any justification for setting (a = - c^2), i.e. it refutes itself, but I already found some hilarious mistakes in it, so if you like I will post them tomorrow.

Also If you still insist that we can set (x = v / t) at (x' = 0) if we are not using the Galilean transformation, I will post the consequences of this mistake on the other derivation too, then if you still insist that we can, then I will try to expalin why it is a mistake, but it will be very boring and long, and involves explaining geometry and dynamics from the very beginning, but for now let me put it this way, (x = v / t) at (x' = 0) is a result of the Galilean transformation, you can't use it by itself.--Ahmadgad (talk) 00:03, 30 September 2010 (UTC)

As I said, publish, and prepare to receive your Nobel Prize in Physics. ħuman 02:11, 30 September 2010 (UTC)

The time origin in both frames is set at the moment the origin of one frame passes the other. As a result, x=0 and t=0 when x'=0 and t'=0. As a result, w1 and w2 are satisfied (for this one point in space-time only), and but nothing past that follows because you divide by t, which is zero in this case. --Quantheory (talk) 02:24, 30 September 2010 (UTC)

I'd like to note that the fact that you made a straightforward division-by-zero error and didn't notice, says to me that you are way more interested in trying to poke holes in relativity than in trying to understand what's actually being said. I have no doubt that you've found hilarious errors in the other derivation, but I think the hilarious errors are in your understanding of the material, not what it actually says. By the way, if the paper doesn't explain why a=-c^2, that's not a "refutation", it simply is a part of the derivation that is incomplete. Nor is it true; the paper justifies the choice a=-c^2 by noting that this is the only transformation that turns points on the light ray x=ct into points on the light ray x'=ct', which is the requirement for an invariant speed of light, which is a consequence of Maxwell's equations and the principle of relativity (which predates the theory of special relativity by several centuries). --Quantheory (talk) 03:08, 30 September 2010 (UTC)

Easy Edit

“You are way more interested in trying to poke holes in relativity than in trying to understand what's actually being said”, no, here is what I did and what I am currently trying to do:

-I started learning about relativity and modern physics about 4 years ago, just out of curiosity

-I read some texts, articles and books about them

-I watched some videos, documentaries and lectures them

-I read about the paradoxes, and the predictions from different sources, though I knew about many of them since I was a child

-I started to examine the mathematical structure of the theory and the various derivations

-I found it hard to follow the logical procedures of some of them, I found others strikingly wrong

-I said to myself, OK, maybe I am stupid and can’t understand them, Einstein and modern science can’t be wrong and I am right

-Every now and the subject grabbed my interest again

-About a year ago I started to reexamine the whole thing

-I found some of the derivations completely wrong again, so I started to doubt their validity

-I visited some anti-relativity sites, but found most of them cranky

-I also found that there are some respected scientists who doubted relativity, ok, and I thought ok, maybe I am not that stupid

-I thought “extraordinary claims requires extra-ordinary evidence”

-I had no time to examine the evidence at that time, so I let it go

-About two weeks ago I started to examine the whole thing again

-I knew that I can’t rely on the predictions as evidence, because I know about Ptolemy’s earth-centric model

-I examined some of the derivations word by word, and symbol by symbol, including the simple derivation we are debating

-I searched for some sites opposing relativity, and this time I found some which weren’t so cranky

-I searched for a site to debate the issue with, maybe someone could me prove wrong

-I posted here, maybe I sounded like a crank, but I was very upset about my findings, yet maybe I am a crank

-Everyone who commented, considered me a crank, which asserts that attacking relativity is off-limit for scientists, or science fans

-I posted some arguments nevertheless

-I found someone ready to debate the subject, you, but your responses didn’t convince me

-I choose to focus on the derivations and mathematics, because without we have no theory at all

-I focused on the simple derivation, because it is the simplest, and it was written after theory was proposed by more than ten years, so I thought it offers Einstein final views about his theory

-We kept debating several points, but you didn’t convince me, and I couldn’t convince you

-I decided to focus on one point or argument, to save time

-I decided to narrow the subject of the debate for (is $x=vt$ at $x^{\prime }=0$ true or false), because it’s the common point in most derivations, and has the most powerful consequences if proven wrong

Regarding the rest of your response, you are forgetting that it wasn't me who suggested the origin to make this calculation, it was Einstein, here is this portion of his derivation again (in his own words, or at least the words of the translator):

" We obtain the equations

x' = a x - b c t ............(5a)

c t' = a c t - b x ..............(5b)

We should thus have the solution of our problem, if the constants a and b were known. These result from the following discussion.

For the origin of K ' we have permanently x ' = 0, and hence according to the first of the equations (5)

x = b c t / a

If we call v the velocity with which the origin of K ' is moving relative to K, we then have

v = b c/ a

The same value v can be obtained from equations (5), if we calculate the velocity of another point of K' relative to K, or the velocity (directed towards the negative x-axis) of a point of K with respect to K'. In short, we can designate v as the relative velocity of the two systems.

" (end of quotation)

So you want to say that when Einstein says "For the origin of K' we have permanently x ' = 0" and "If we call v the velocity with which the origin of K' is moving relative to K", he is not talking about the origin where x'=y'=z'=t'=0, because according to you I was the only one who divided by zero, but he didn't.

I really don't get it, you understand perfectly that at the origin of k', we have x=0 and t=0 and x'=0 and t'=0, but you don't object Einstein saying that at the origin we have (v = x / t), i.e. (v = 0/0)!

And you can't tell me that he meant by the origin the point where x'=y'=z'=0, with an undetermined value of t', no, we are talking about a 4-dimensional set of coordinates, space-time coordinates, so typically the origin is when-where the 4 dimensions equal zero.

However, we can agree to omit the word (origin) of the discussion, and let's assume that he only meant the moving point where x'=0, but even if we did, we will still have (v = x / t) is false, and let's examine why.

To measure the velocity between a point and a line, you will have to pick a random point on the line and measure the rate with which the distance between these two points is changing (dx/dt):

speed = (change in distance between the moving point and a random point on the line measured in units of length) per unit time

Or you can pick two random points on the line, measure the distance between them, then divide it by the time it takes the moving point to cover this distance:

speed = (distance between two random points on the line)/ (the time with which the moving point cover this distance)

Now this implies that we have a universal method to measure both absolute time and distance, and no matter what space-time coordinates you are using, the relative velocity between the two objects will be the same, which is exactly what you do when you say that the relative velocity between the two frames k,k' is (v).

What do you mean by by that if you don't have a universal method to measure absolute distance and time? nor having a third frame k to measure each frame's velocity in comparison to it before comparing them to each other, should we measure this velocity according to frame K or K' or k, knowing that each one of them have different standards for coordinates, but not knowing the transformation factors between this coordinates.

In other words the Galilean transformation assumes the existence of a universal and absolute time, and the possibility of measuring absolute distances, but at the starting point for deriving the Lorentz transformation, we don't know this yet.

Now let's apply all of this to our case, in which Einstein says that the "moving point" x' = 0 is moving with a speed (v) relative to k along the positive x-axis(or collection of points, as x' = 0 may include all the points on the y', z', t' axis, not just the origin of k') , which is not perfectly articulated, but can be understood or reduced to (the moving point x' = 0 is moving with a speed (v) relative to the line represented by the x-axis of frame k).

Now you have two options to describe this speed, deduced from the definitions of speed in general:

(1) speed = (change in distance between the moving point and a random point on the line measured in units of length) per unit time

(2) speed = (distance between two random points on the line)/ (the time with which the moving point cover this distance)

To match definition (1), we choose the random point to be x = 0, then we reduce our case to ((the moving point x' = 0 is moving with a speed (v) relative to the resting point x = 0), then (v) will be:

v = (change in distance between x' = 0 and x = 0 measured in units of length) per unit time

Now this definition holds true only if you assume the existence of a universal and absolute distance and time, because it assumes universal units of length and time, but according to you the units to measure time and space might be different between k,k', we don't know the transformation factors, however, this isn't the way we usually measure speeds, i.e. we don't measure rates of change in distance in reality.

In reality we use definition (2), then reduce it to definition (1), after all we do distinct speeds using (m/s), so according to definition (2), at any given moment, we reduce our case to:

v = (distance between: the current location of the projection of x'=0 on the line (x-axis), and the resting point x = 0) / (the time difference between: the time reading when the projection of x' = 0 was located at x = 0 (which is zero in our case), and the current time reading)

Again we have another dilemma, which distance and time difference are we talking about? are they measured from k or k', here you insist that they should be measured from k, and (v = x / t), but we must ask ourselves, does the definition of x,t match the distance and time in the definition of (v).

So let's examine the definition of x, so for x' = 0 we have:

x = (distance between: the current location of the projection of x'=0 on the line (x-axis), and the resting point x = 0)

Now my question was "then what is exactly is stopping you from saying that (v = x / t), at (x' = 1, 2, 3,.......etc.)", i.e. why exactly for x'= 1 for example, we don't have:

x = (distance between: the current location of the projection of x'=1 on the line (x-axis), and the resting point x = 0)

What's o special about the point x'=0, that makes this definition only valid for it, as far I know just as you can define ("Right now is t=0"), you can define ("Right here is x'=0"), and in our case you can take any two points passing by each other, one from k, and the other from k' and define them as origins, with coordinates (0,0,0,0).

Your response to my question was: "However, your other equations do not follow", which doesn't answer my question, as you still think that (v = x / t) at (x' = 0) doesn't need a proof, and "that comes from the definition of velocity", what's happening is you are so used to explain reality using the Galilean transformation, so much that your brain is operating according to the Galilean transformation, and you see the result directly, refusing to see that this assumption needs a proof, because what's given is (k) is moving with a speed of (v) relative to k', not (v = x / t) at (x' = 0).

The fact is even if you are using the Galilean transformation, then stating that (v = x / t) at (x' = 0) also needs a proof, so to remind of how things work, let me ask you again, can you proof that (v = x / t) at (x' = 0) using the Galilean transformation.

You are also forgetting that Einstein wrote: "The same value v can be obtained from equations (5), if we calculate the velocity of another point of K' relative to K, or the velocity (directed towards the negative x-axis) of a point of K with respect to K'. In short, we can designate v as the relative velocity of the two systems", but since he is long did, can you do that?, i.e. can you write an expression for (v) for any other point apart from x' = 0 without knowing the transformation equation(s)?.

Another thing missing from this logic is that (v = x /t) doesn't designate an event, however, the whole point of constructing the frames k, k', was to designating events in the space-time, i.e. designating x'=0 is meaningless without designating a corresponding t', in other words, the coordinates of k,k' should be used to locate events, not velocities, nor distances and times by themselves, so you can't use the symbols x, t to describe (v).

Now let's ignore (x) for now, and focus on t, which should be:

t = (the time difference between: the time reading when the projection of x' = 0 was located at x = 0 (which is t = 0 in our case), and the current time reading (which should be t = t in this case))

Now where should this t be measured exactly, I am not asking about which frame, but which point, i.e. the clock reading t = t, is located at which x = ?.

And what is the event that takes place at (t), it's doesn't seem clear to me at all.

You now what, I am starting to forget what I wanted to get at when I started writing this response, and it;s getting long and boring, so let's leave it at here, and if you find my response "cranky", you can ignore what you want fro it, The most important points for me are these two:

"The fact is even if you are using the Galilean transformation, then stating that (v = x / t) at (x' = 0) also needs a proof, so to remind of how things work, let me ask you again, can you proof that (v = x / t) at (x' = 0) using the Galilean transformation."

"You are also forgetting that Einstein wrote: "The same value v can be obtained from equations (5), if we calculate the velocity of another point of K' relative to K, or the velocity (directed towards the negative x-axis) of a point of K with respect to K'. In short, we can designate v as the relative velocity of the two systems", but since he is long did, can you do that?, i.e. can you write an expression for (v) for any other point apart from x' = 0 without knowing the transformation equation(s)?."--Ahmadgad (talk) 00:54, 1 October 2010 (UTC)

So? --Ahmadgad (talk) 11:35, 2 October 2010 (UTC)

"And you can't tell me that he meant by the origin the point where x'=y'=z'=0, with an undetermined value of t'" Sure I can. For one, I've been using the phrase "time origin" out of convenience; it's not a bit of terminology Einstein shares, as he takes "origin" to refer only to the zero of the spatial coordinates. For another, he said "permanently". What would he mean by that except "for all times"? As long as $t'\neq 0$, there's no divide by zero error.

As for your other comments on origins, 5a and 5b were derived for two points that pass each other at t=0 and t'=0. You set clocks at the moment of passing because distant clocks cannot be synchronized in special relativity. It's possible for two points that pass each other to set their clocks at t=3, and t'=5, but that is an unnecessary complication to the theory. Both 5a and 5b would change, but the two changes would be such that the same conclusion would result, so derivations generally declare t=0 and t'=0 to be when the origins pass for convenience. The same goes for setting your clocks at any other position. We could have an observer at x=3 and t=4, and another at x'=4 and t'=-5 passing the first. But then we'd just be adding a lot of extra 3's and 4's and 5's in order to get the same result. In fact, you can turn that scenario into the same set of equations by declaring "I'm now going to keep track only of coordinates $\Delta x=x-3$ and $\Delta t=t-4$, doing the same for $\Delta x'$ and $\Delta t'$, and then I can write the exact same equations, only with my coordinates that have $\Delta$ in front."

"What do you mean by by that if you don't have a universal method to measure absolute distance and time" I have no idea what you mean by this. I never asserted it. In special relativity, a distance between two points as measured in one frame is not the same as the distance between those points as measured in another frame, but the spacetime interval $\Delta r^{2}-c^{2}\Delta t^{2}$ is the same between two space-time points, because it takes into account both time and space. It's like rotation; if I rotate a vector by 30 degrees, the x-direction component of the vector may not be the same, but if I take into account all coordinates, the total length of the vector is the same. Even though the individual coordinates change, the laws of physics remain the same if I tilt my coordinate system and run all the calculations again.

In fact, the situation is almost exactly analogous. What this derivation implies is, mathematically, that changing to a different coordinate system is a sort of rotation in space-time.

In a simple, 2-D Euclidean scenario, if you rotate a coordinate system by 30 degrees, moving 1 unit in the x direction in one is not the same as moving 1 unit in the x' direction of the other (the directions are different). However, in either coordinate system, you can agree on the magnitude of the angle between the two systems, and on the total length of vectors. In an analogous way, in special relativity people can disagree about distances and times individually (because "to the left" in one system may be "to the left and slightly back in time" to the other), but when they take all coordinates into account, they get a) the same spacetime interval between any two points, and b) the same relative velocity between the two observers.

There is an important difference, however. Your everyday, Euclidean geometry allows you to add angles, but in special relativity you can't add velocities, because the speed of light is always the same (although you can add "rapidities", which are a function of velocity). As a result, if $K$ and $K'$ agree that they have a relative velocity $v_{1}$, and $K'$ and $K''$ agree on a relative velocity between them $v_{2}$, and the same for $K$, $K''$, and $v_{3}$, someone in $K'$ can calculate $v_{3}$ with the transformation, but it is not the simple calculation $v_{3}=v_{1}+v_{2}$.

This conversation is long enough already, so let me cut to the chase. So far as I can see, special relativity states that:

1. Maxwell's equations work.
2. The principle of relativity (no one inertial reference frame is more special than any other) makes sense, and has never been observed to be violated.
3. If Maxwell's equations work equally well in all reference frames, the speed of light must be the same in all reference frames.
4. Galilean transformations do not allow a constant speed of light (because velocities can be added, therefore the velocity of light coming from a train moving at 5 mph is c+5 mph).
5. We find that there's another possibility, called the Lorentz transformations, which do allow a constant speed of light.
6. Therefore, it may be possible to formulate a consistent electrodynamics using the Lorentz transformations, but it is impossible to do so relying solely on the Galilean transformations.
7. Therefore, it's more reasonable to see the Lorentz transformation coordinates as describing the "real" transformation between inertial reference frames, than the Galilean transformation.
8. As a bonus, one gets mass-energy equivalence from calculations of kinetic energy in special relativity.

Most of this predated (or was invented independently of) Einstein; his paper on the subject was largely reasserting earlier work and adding the last couple of points. You know, "shoulders of giants" and all that.

Which of the above points do you actually disagree with? --Quantheory (talk) 01:05, 5 October 2010 (UTC)

observational evidence

So, what observation in the natural world would disprove relativity as we know it? 'Cause the math is interesting and all, but if it doesn't describe the real world, who cares? sterile politician 13:38, 2 October 2010 (UTC)

Other than quantum mechanics being incompatible with it, showing that either time dilation or spacetime curvature did not make predictions compatible with reality would kill it dead. Wisest harmonic Hoover! 19:27, 2 October 2010 (UTC)

Gravitational lensing was a big deal for general relativity, although before that there were experiments with the bending of the path of light, and regarding the perihelion of Mercury (more here). Perhaps the most likely place to find violations of general relativity would be around black holes, where the predicted consequences of GR are extremely strong. One would expect to find evidence of even mild inaccuracies there. Other possibilities would be Big Bang cosmology, movement of galaxies/galaxy clusters, further findings regarding "dark energy"... By the way, although special relativity is pretty much settled, general relativity doesn't have anything near the dogmatic following asserted by the OP. --Quantheory (talk) 03:18, 5 October 2010 (UTC)

A plead for TeX

<math> tags can be used to insert arbitrary bits of TeX into posts; please do so. If you don't know TeX, then some doubt is thrown onto your legitimacy. Wisest harmonic Hoover! 12:20, 2 October 2010 (UTC)

Problem with Intro

In the introduction Ahmadgad writes:

• OK, "Conservapedians" are wrong about almost every topic they handle, except relativity, I am an atheist (ex-Muslim)and a libertarian socialist, but I agree with them on this one, of-course they offer no coherent criticism of relativity, but they are right in saying that serious criticism of relativity is suppressed by the scientific community."

In fact the scientific community is quite happy to criticize relativity. New Scientist recently ran an article criticizing Conservapedia's relativity article. In their conclusion they said:

• "Despite the fact that it has passed test after test, you would be hard-pressed to find a single physicist who believes that general relativity is ultimately the correct theory of the universe. That's because it conflicts with quantum mechanics and is yet to be unified with the other three forces of nature. A theory of quantum gravity such as string theory will be needed to pick up where Einstein left off. General relativity is certainly not wrong – but it's not the whole story."

So I does not seem that your statement "criticism of relativity is suppressed by the scientific community" can be wholly correct.--Bob^{Spring is sprung!} 19:41, General relativity is certainly not wrong – but it's not the whole story.2 October 2010 (UTC) Italic text

Hi Bob: When in you quote "General relativity is certainly not wrong – but it's not the whole story", please tell me which general relativity is meant, since we have here at least a choice of 3 GR's: (1) Wheeler's GR from his 1973 "Gravitation", with its expanding universe, unfortunately with wrong sign of acceleration of expansion, which contradicts 1998 observations of Supernova Cosmology Project by more than 6 standard deviations (as astronomers from my university say), which is certainly wrong and (2) adjusted for right sign of acceleration considered right by everybody except me, also expanding, and (3) an old Einstein's GR, from 1917, considered wrong by almost everybody but me since his theory predicted these observation with better than one standard deviation accuracy. So is it that someone else discovered this things about Einstein and has the same problems with publishing them as me? I did not see them published anyplace yet except in my Essay. JimJast (talk) 21:53, 19 March 2011 (UTC)