In another thread, Confused2 asked what Lorentz Invariance meant.
I found an awesome explanation on this subject:
Nothing but Relativity.
This also throws out a lot of the bunk ideas mentioned in some current threads. Anything that asserts that "Einstein was wrong" must also assert that at least one of the simple assumptions in this paper is wrong:
* Moving from reference frame S' to S will exactly undo moving from S to S'
* Motion in one direction is the same as motion in the other direction (looking at one space dimension, x, only here)
* A rod in S will be viewed to have some length in S'. That length will be the same no matter where in x the rod is located.
* Ditto for time, but harder to explain. A certain amount of time passes in S, seen as some interval in S', will be the same if you repeat the experiment later.
From there he deduces the most general form of a transformation from S to S' that satisfies these assumptions. Any valid theory must be a special case of this formula. Only two do: The absolute time of Galileo, or the Lorentz transformations of Special Relativity. If you were to make up some different function for reference frame translation, or for adding velocities, it would violate those 4 assumptions and you have some more explaining to do.
It can be proven that , if one uses only the principle of relativity and one neglects the principle of light speed constancy, one can rederive SR. In addition to the above derivation, one can obtain the second principle as a consequence of the principle of relativity. It has been done very ellegantly by many authors.
Zephir
21st June 2007 - 09:06 AM
QUOTE (LearmSceince+Jun 21 2007, 07:59 AM)
...I found an awesome explanation on this subject: Nothing but Relativity....
The relativity cannot explain the Lorentz invariance by its very definition, because it's using it as a introductional
postulate, i.e. the
assumption, which is accepted without proof.
Like I've explained in the
another topic, if we admit the luminiferous Aether concept, the Lorentz invariance is the trivial consequence of the fact, the light is the only wave, which is used for observation and the relativity has nothing to do with such explanation. We can observe the Lorentz invariance even at the water surface, if we disable the using of the light both for time, both for space measurements.
Guest_mott.carl
21st June 2007 - 12:19 PM
rpenner
why in your oppinion,the rotation is not good symmetry?
the quaternions would be the minkowkian space M4,with 3-dimensions spatial,and
1 dimension- imaginary,that is time.the time in it flow,have not any relations with
real numbers.sure?
then the multiplications of quaternions implies not the existence of 4-dimensions,generate the fourth-dimension,through of non-comutative rotations,that
in the spacetime,lead us to discontinuos entities.
greetings
rpenner
21st June 2007 - 02:35 PM
Actually, I have ZERO evidence that the laws of physics aren't rotationally invariant.
But the last time I looked at the 3-d pixel universe idea, which seems to have come up again recently, it fills the universe with space-filling cubes which do have preferred orientation and would tend to cause all the laws of physics to be asymmetric with respect to direction. Of course they could postulate that "the laws of physics conspire to hide the underlying orientation of the cubes," but the hypothesis of such a conspiracy causes the first idea to retreat to a untestable metaphysical hypothesis.
A similar metaphysical hypothesis is: "The Universe is just God's dream and the reason the laws of physics appear mathematically consistent and exact and eternal is that God's dream is very mathy compared to human dreams." Untestable and therefore not-physics. It's metaphysics.
The shorter statement: "The Universe is just God's dream" is physically inconsistent with observation if dream has its usually anthropocentric meaning.
LearmSceince
21st June 2007 - 06:49 PM
QUOTE (rpenner+Jun 21 2007, 06:16 AM)
Actually, Rotations are part of both the Galilean group and Lorentz group, but except for the 3-d pixel universe most cranks think rotation is a very good symmetry of nature, so its much less controversial than most topics.
I've seen people here that refuse to accept that time is relative etc.
QUOTE (rpenner+Jun 21 2007, 06:16 AM)
Another post along these lines
Interesting. Basically the same idea: Define what is meant by "relative" in strict terms, in that "here is just like there", without explicitly adding in features that are not already in Galilean Relativity. You wind up with the general form that includes a free variable. Expressed as simply a constant that was introduced, K. You called it c². I didn't follow through the math to see if it started out as C when introduced, or if you called it that to "lead the witness". But, given the original input units of distance and duration, the simplest form that would seem to have physical significance is 1/K² which is a velocity. Redefine C=1/K² as the free variable and write the function in terms of C, and then interpret C as a special velocity that can be found by experiment, that is the asymptote of velocity addition and invariant in any reference frame. If K is positive, you can experimentally find this velocity.
Note that the paper I cited doesn't do any rotation. It uses translational symmetry in space (one dimension) and time. The fact that the resulting function fits that of hyperbolic trig functions can be recognized and used as a toolset, but it didn't use any of those tools to get there. Not even real calculus! Galileo could have done the limit easily.
LearmSceince
21st June 2007 - 06:55 PM
QUOTE (Zephir+Jun 21 2007, 09:06 AM)
The relativity cannot explain the Lorentz invariance by its very definition, because it's using it as a introductional
postulate, i.e. the
assumption, which is accepted without proof.
I agree that the 4 postulates are a subset of Lorentz invariance. What is deduced is that, given that "space is the same everywhere, time is the same everywhen", you get length contraction, time dilation, and lack of simultaneousness.
mott.carl
21st June 2007 - 06:57 PM
thank you very much for your reply,RPENNER
the symmetry of rotational invariance would be connected with the fusion of space
and time in primordial vaccum.
the could to think that the quantum entanglement with twin paradox,through of the
opposed spins transformations.the differences between the left-right spins(generates the variations of space and time;it is time-dilatation and contraction of space)
LearmSceince
21st June 2007 - 09:14 PM
QUOTE (mott.carl+Jun 21 2007, 06:57 PM)
the symmetry of rotational invariance would be connected with the fusion of space
and time in primordial vaccum.
Rotational invariance would not require any concept of time. You can have it in plane geometry.
QUOTE (mott.carl+Jun 21 2007, 06:57 PM)
the could to think that the quantum entanglement with twin paradox,through of the
opposed spins transformations.
That doesn't scan.
QUOTE (mott.carl+Jun 21 2007, 06:57 PM)
the differences between the left-right spins(generates the variations of space and time;it is time-dilatation and contraction of space)
That doesn't make sense either. If I play fast and loose with the punctuation and some transitions and linking verbs, it still doesn't make sense. What does the phrase outside the parens have to do with the predicate and independent clause inside the parens?
If nobody can make heads or tails of your words taken in small groups, how can anyone hope to understand the point you are trying to make? Why do you post this? Can you not perceive that it's all scrambled? I think you should proof-read what you wrote before hitting the (add reply) button. Many people can't proof their own writing shortly after writing it, because they know what it is supposed to say. If that is your case, then you need to ask someone there to look it over before posting. Otherwise you should be embarrassed for posting gibberish and not even realizing it at the time.
AlphaNumeric
21st June 2007 - 09:36 PM
^ Precisely what I've been saying to Mott, he just doesn't want to listen. Anyone clever enough to grasp the concepts Mott claims to do work on would realise that they can't speak a language well enough to be understandable.
Therefore, this leads me to the conclusion Mott is aware of, even exaggerating, his poor English in order for those unfamiliar with such areas of physics to be fooled into thinking he's saying something profound or interesting about a difficult topic. Infact he's just spinning BS.
LearmSceince
21st June 2007 - 09:46 PM
QUOTE (AlphaNumeric+Jun 21 2007, 09:36 PM)
^ Precisely what I've been saying to Mott, he just doesn't want to listen. Anyone clever enough to grasp the concepts Mott claims to do work on would realise that they can't speak a language well enough to be understandable.
Therefore, this leads me to the conclusion Mott is aware of, even exaggerating, his poor English in order for those unfamiliar with such areas of physics to be fooled into thinking he's saying something profound or interesting about a difficult topic. Infact he's just spinning BS.
I've worked with people who were poor at English, and exchanged messages with people at various levels of proficiency. People who are poor at English will still be sensible in a larger sense. Mistakes will be typical, involving using the wrong grammar (as opposed to no grammar at all), systematically forgetting articles or inserting gender-specific articles, confusing singular/plural forms, and not using irregulars "correctly".
This writing looks more like a Functional Thought Disorder.
mott.carl
21st June 2007 - 10:14 PM
learnscience-excuse me,but you know anything of physics or mathematics.only
this.
alphanumeric,is just the parrot of cold country.
do you understood what i wrote on spins,rotational invariance? NO.
LearmSceince
22nd June 2007 - 11:13 PM
QUOTE (mott.carl+Jun 21 2007, 10:14 PM)
learnscience-excuse me,but you know anything of physics or mathematics.only
this.
alphanumeric,is just the parrot of cold country.
do you understood what i wrote on spins,rotational invariance? NO.
I understand that last line. I wrote a whole post saying I did not understand what you wrote. Nobody can understand that post.
The first part of the previous post I don't understand. If "parrot of cold country" is an expression in some other language that has been literally translated, I can't find any references to it on Google other than by you! What is it supposed to refer to? As for "you know anything of physics or mathematics" that is not proper English, but I think you meant, "You know everything about physics and mathematics (we can ask you anything)." Thanks for the compliment. It just seems that way because I only answer things I know, and have not asked anything <g>.
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