Age And Relativity

[sigurdV]

Well, it's your wording. If you don't like it, try "Two events occurring at points p and q of an inertial frame F are simultaneous if and only if light emitted at the two events arrives at the same time at the midpoint of the segment pq in F."

 

The point is that what is simultaneous in frame F (F's perspective) is not simultaneous in different frames. Again, this is a direct consequence of the invariant speed of light, as demonstrated in the youtube clip I posted above.

 

Good try but it fails: "at the same time" is just a synonym for "simultaneous"...I tried it myself while realizing that the problem of replacing the explanans in the explanandum may be impossible or extremely complicated. (Otherwise it would have been done already.)

 

I think it is time to show my cards, I dont think Relativity is inconsistent: it is an indispensable tool for engineering processes close to the speed of light. It has proven its worth in practice again and again. But that is not the whole story...The question for me is what the Theory of Relativity reveals about our world! ...And what its advocates THINKS it reveals!

 

Nothing travels faster than light, they say...When asked about the relative velocity of two points very far away from each other they realize that because of the expansion of the universe such points recede from each other with a speed far exceeding the speed of light,and slightly embarrassed they hasten to add that their results did not apply to space itself and that Relativity is a local theory. Fine with me but why didnt they say so in the first place?

 

Id like to coin a word: Conceptual Imperialism!

 

You take a word like "Frame" from ordinary language give it a special technical meaning

within your theory then you claim that the original concept should be replaced with your new concept.

 

"Frame" has a long history it can be traced ( as CraigD told me) back to the Indoeuropean Language, I expect it to be traced all the way back to Nostratic the origin of ALL European plus some more languages. I think its root is among the first human words, like for example "Gnaw" which now have been traced to The Original First Language! The Primitive Human/Humanoid in naming objects realised the need for a word designating the limit of objects... and we have it still here with us.

 

The case of "Frame" really is an easily explained oversight on the part of Relativists

( When they claim there is no universal frame they mean that whatever frame our universe may have ,we can be sure its not an inertial frame.),but what I see on "Instant" and "Simultanity" worries me! The claim seems to be that there is no simultanity since different observers measure it differently... Our difficulty in measuring a phenomenon does not, to my knowledge, in any way prove the non existence of it!

 

Then there is the case of proving that instant signaling is impossible since signals could then be sent back in time... There is of course entangelment to consider but I always had my doubts about the time travelling of instant signaling and seing the "proof" makes me suspect we have here a case of Scientific Myth! Now...that! would be a story to tell,wouldnt it?

 

PS Hi craig! I didnt notice you. Im perhaps repeating myself some here but...Well. On first sight everything you write looks reasonable as usual, a closer look will have to wait until next week:)

 

PPS Your beginning is not only reasonable its outright funny!!

 

Hmmm...I thought todays writing was over but i feel i should comment on the following:

 

"I’m saying essentially the same thing JM did, in a couple of sentences, here:

 

JMJones0424, on 08 July 2011 - 03:49 AM, said:

 

You find it hard to believe because you are still stuck in the classical mindset with absolute time and universal simultaneity."

 

That might indeed be so, but I also have another reason for resistance I never intended to let surface: I have a conscious picture of the sort of situation Im in.I dont want to change it, so I defend instant signaling since it occurs in my world model...

 

There is a bucket of paint, and here is a ball symbolizing the singularity at the origin. Its dipped into the paint and put to dry.Now the paint layer is the universe at its first instant (This "time" is quantified ok?) Mysterious things goes on within the paint layer but no time (of ours) passes since the ball is not yet dipped again into the paint. Them mystic processes might have one or more time axises added to the layer so there can be ordered processes,who knows? But their existence will not effect time in the model which consists of layers of paint.There might be observers and experimentators in the layer.. But they cant yet act.

Now comes next moment=next layer of paint: the universe repeats is mysterious business and participators now have the possibility of having inside them a picture of themselves in the first layer,but they still cant look at it... and so on.

Each layer contains instant signals and every place in a layer exists simultaneously.

And I will adopt any simple model making more sense.

 

Most objects I thought of can be put into the model: The past is in a sense all there is, the future does not exist and the mind and the present (elusive things as they are) might be an interaction between the uppermost layers. The expansion of the universe takes place inside the layer (it being infinitely divisible) and so on... It even has Moral Consequences:

What you did is always there:)

 

So (in order to tell you why I told you this): I dont think prejudice is the best explanation of my actions or wiews...

 

Perhaps relativity should be put in there as well...Maybe add a dimension or two...Hmmm not yet! And not by me! I would like to see the history of our universe repeated in the model as it is...Perhaps three space dimensions are necessary for...whatever they are necessary for.

 

The ball seems a clumsy thing can we replace it with a point? Nah! We dont know much about the original singularity do we? Ill leave the introduction of metrics and all the rest of physical paraphenalia as an exercice for the interested reader. This was never in the foreground, never really caught my interest, it was just my simple consistency test ground of ideas about reality.

 

PS If we really want the layers to be three dimensional I guess we could make them holographic. I like looking at our world from the outside.But then its no longer OUR world is it? The inhabitants could look back!

[JMJones0424]

Good try but it fails: "at the same time" is just a synonym for "simultaneous"...I tried it myself while realizing that the problem of replacing the explanans in the explanandum may be impossible or extremely complicated. (Otherwise it would have been done already.)

Look, if your intention is to mentally masturbate over symantics, then by all means count me out. Math is the language of logic, not English. Though it has already been linked twice, the wiki article on relativity of simultaneity goes either unread or misunderstood by you. How do you define simultaneity? Would you agree that two events are simultaneous to observer F if and only if the two event's light cones intersect at F's world line? If not, why not? Would it make a difference if we called that intersection fluegenmiken instead of simultaneous?

 

And you wonder why philosophy is dead as a natural science. There's an xkcd comic that's appropriate, I might waste more of my time on this thread and find it.and easy to find as it is applicable far too frequently.

[sigurdV]

It never was my intention to make people angry, suddenly i had lots of text to read and lots of links to visit ( Heaven Surely? )... that Wikipedia link seems fine, Relativity is doing fine except for a definition that seems to break the rules given in logic textbooks for proper definitions.

If it really is impossible to improve the definition why not close our eyes and pretend there is no problem? And is there a thought experiment purporting to show instant signals signalling into the past,showing nothing of the sort? Go ahead throw stones at me, science really needs that kind of defence.

 

Must events be observed to be simultaneous? Why the obsession with observers trying to measure simultaneity? Isnt it reasonable that it cant be exactly measured by beings inhabiting inertial frames? I suspect all you see while looking at my text is some fool dreaming to prove Einstein wrong? Dont you??

 

I already stated that i define simultaneus events being so by having the same distance (in time) to the origin of our universe and i dont understand the fuzz about it. Do you aim to prove that the definition given above by relativity is the only acceptable one? If so publish your argument and ill be happy to check it.

 

Ive also, really against my better judgement, tried to give a simple model of how I (poor old student that I am ) think instant signaling and simultanity fits into a picture of a world... What more should I do? I have just kissed a photo of Albert Einstein , am i now forgiven for my sins and can we now continue a serious discussion? I am sorry I lost my temper, something surely you scientists never do.

 

I think somebody made a promising point somewhere: Perhaps simultanity CÁN be measured WITHIN an event!?

 

EXCELLENT!

 

But i fear that the concept of simultanity used within the event may not be the same concept as the one defined by the definition i have troubles with. Still i suppose definitions like mine (were they acceptable) could be used reluctantly but successfully by relativity (no circularity) for that purpose and that purpose only:)

 

(In case the reader misses my carelessly prepared point, then notice that the age of the universe in event x must be the same as the age of the universe in event x)

[JMJones0424]

I am upset by your ruse. You started this thread in a science forum's Q&A section, when you have exhibited zero interest in understanding the concepts you seek to supplant. You edit posts after they have been replied to, which is just bad form. You post some bad scifi word salad crap that belongs in the silly claims forum as your revelatory model, yet don't know enough about the subject to spot the inconsistencies, even though had you made an effort to comprehend the posts in this thread it would be obvious. You might as well have said it's turtles all the way down.

 

But hey, even though you ignored my alternate definition of simultaneity above, you did manage to provide your own?

 

I already stated that i define simultaneus events being so by having the same distance (in time) to the origin of our universe and i dont understand the fuzz about it. Do you aim to prove that the definition given above by relativity is the only acceptable one? If so publish your argument and ill be happy to check it. Ive also, really against my better judgement, tried to give a simple model of how I (poor old student that I am ) think instant signaling and simultanity fits into a picture of a world... What more should I do? I have just kissed a photo of Albert Einstein , am i now forgiven for my sins and can we now continue a serious discussion? I am sorry I lost my temper, something surely you scientists never do.

 

The fuzz, of course, is that I have presented an argument, which is not my own, as it has been formulated and tested repeatedly by millions of individuals, and have striven to understand where I was failing in the explanation. Meanwhile, you claim to accept relativity, yet your word salad betrays you. What I would like you to do is please, in your most eloquent and logically consistent prose, submit your theory to the Nobel committee and claim the prize you so richly deserve. Forgive me for mistakenly believing your intention was to understand one of the most thoroughly tested, logically consistent, and usually, easy to understand scientific theories that mankind has prized from nature in an unbroken thread through the ages of those who value reason and observation over superstition and revelation. Sadly, though we are both using English, it is apparent that we are speaking entirely different languages.

[sigurdV]

I did not ignore your definition, i only did not find it an improvement.

I missed your argument, all I saw was to me irrelevant questions...restate it or tell me exactly where in your writings it can be found.

I dont care if it was developed by others...if you use it you defend it.

I like science fiction.I wish I could write it.

I edit because i dont like spelling mistakes and windy expositions.why waste space?

I will check the rules of the forum to see if the practice is allowed or not.Meanwhile i inform those whom it may concern that I indeed edit and my writings get shorter by time.Especially in unvisited threads.

Im not sure what you mean by me not understanding Relativity...sure it was a long time ago since i read about it so all detail is gone,also my ability to calculate is weak...but i remember,sort of, what I found in the theory.I wasnt aware one has to read the whole book before one may discuss the introduction.

I dont want prizes,i want competent readers. Telling me not what they think of what i write but instead tells me exactly what mistake was done.Or how else the text can be improved.

There are such readers.It seems you have been reading most of what i have written. Thank you!

It reminds me that i should take away most of it since it was done by the left hand while i was pondering Quantum Theory.Something you probably find me incompetent to do.

And talking about what is considered good manners in here, do you consider suggesting my intention is mentally masturbating over sYmantics an example of good manner?

I felt it as a personal attack. But if you tell me im mistaken ill believe you. (I think.)

[CraigD]

It never was my intention to make people angry, suddenly i had lots of text to read and lots of links to visit ( Heaven Surely? )... that Wikipedia link seems fine, Relativity is doing fine except for a definition that seems to break the rules given in logic textbooks for proper definitions.

If it really is impossible to improve the definition why not close our eyes and pretend there is no problem?

Sigurd, I’m not angry with you in the least, but hope you intend to actually acquire at least an introductory knowledge of physics, because I believe some of the most important ideas require this knowledge. As the xkcd comic notes in a fun and funny way, people with at least a modicum of math and physics education tend to believe that physics really can’t be appreciated without it. Like most subject, before your opinions and ideas will be taken seriously, you must be able to demonstrate that you understand the subject by being able to complete common academic exercises in it.

 

Until you do, you’ll likely encounter reactions like JM’s considering your writing to be “bad scifi word salad crap that belongs in the silly claims forum.” Worse, you’ll be depriving yourself of understanding some profoundly beautiful ideas.

 

I will check the rules of the forum to see if the practice is allowed or not.

Though it’s not mentioned explicitly in the rules, editing your posts to correct mistakes is encouraged. Adding substantial new content should be avoided, as it’s confusing to readers who have read your original post. Changing the meaning of your posts – which I don’t believe you’ve done, Sigurd, or would do – is considered deceptive, and strongly discouraged.

 

When you do edit your post, it’s good form to enter an “reason for edit” and check the “show edit by line” box, so that readers know you’ve edited it.

[sigurdV]

On the contrary, instant signals must arrive before they were sent (from the receiver's perspective). That you assume instantaneous communication is possible is the inconsistency,

 

What we see lies always in the past since rays takes their time to reach us,except when a signal is instant so the picture of someone sending an instant signal arrives after the signal itself.

 

Should that make us believe that the signal really arrived before it actually was sent!? That Is To Confuse The Event Of Sending The Signal With The Event Of Seeing The Instant Signal Being Sent!

 

Hands on Hearts... How many of you has done this mistake? Or spoken "lightly" as if you had?

 

I ask because such a mistake seems to be made in the Max/Maxine experiment, and

(i suspect) in any experiment where instant signals are found in the past.

[sigurdV]

Ive checked the chapters and there are no new contents in Special relativity I was not aware of before... It hurts to be considered an Ignoramus of Physics! (Especially by Ignoramuses of Reasoning.) My problem lies in using and ,to some extent, understanding the Mathematics involved. The first needs practise, practise "wastes" time... but I always felt I should understand what, for example, Tensors are. So, CraigD , despite being ridiculed in here i will persevere. BUT no quick results will be promised!

 

Meanwhile scientists really should try to see things from my frame... It can perhaps be explained away as an exercise in objectivity: I arrive here among presumed scientists and find them in general unable or unwilling to study ,understand and present arguments!

 

Unproved you say? Take a look at my argument in The Final Solution of the Liar Paradox. There I imply that is unsatisfactorily to use a contrafactual assumption (all the while knowing the same result can be gotten another way) and did anyone show us how?

 

I suddenly remember you talking of publishing in "something peer reviewed", is there such a thing?

[JMJones0424]

OK, I flew off the rails there for a bit. For some time, I have held the belief that if people approach the subject of Special Relativity honestly, they will see that denying it is as absurd as denying that the Earth orbits the Sun. My last two posts have reflected the frustration I feel as I come to realize that perhaps my belief in the obviousness of Special Relativity is incorrect.

 

I do not think it is necessary to employ complicated mathematics to show where you have gone astray in some of your comments in this thread. However, to support your position, you do indeed need to employ some math, as you directly contradict the better part of mankind's discoveries in physics over the last 400 years. Too often people react as if special relativity was a concept that Albert Einstein dreamed up one day while bored in a dead-end job, and that their idle fascinations are on equal footing, though they lack the ability to test them and the prestige to convince those that could test their ideas that the tests are worthwhile. I think the major hang-up is that at the scales nearly everyone experiences on a daily basis, Newtonian Relativity and Special Relativity are practically indistinguishable. However, some of the consequences of Special Relativity differ so dramatically from every day experience, that people tend to question intuitively their validity. I ask you instead to truly learn what Special Relativity is, and then, if you still wish to propose a system that contradicts SR, be prepared to show the math to back up your claims. I am not a professor. I am not formally educated in the pertinent subjects. I know for a fact that the majority of the regulars here are more qualified than I am to correct your conceptual errors. However, if I wish to maintain the illusion that SR can be explained without "eyes glaze over math", then I should be able to concisely correct at least some of the major errors you have made in this thread. I certainly do not claim to be an expert, and wish to be corrected when I am incorrect, as it will help my understanding. I will do my best to make the remainder of my replies to this thread stand on their own, but I am not going to write a textbook. I will provide links to supporting material if a particular concept has not yet been covered in this thread. So, with that in mind and with a clean slate...

 

 

 

You opened this thread with a common question that includes some fundamental assumptions that are incorrect.

How does measuring the age of our universe fit in the framework of relativity?

 

Isnt an exact measure equivalent to absolute time? I then expect relativity to set a limit as to how exact we can measure the age of the universe... Otherwise we could make clocks showing absolute time...Or?

 

1. Exact measurements of time and distance are only absolute in one's inertial frame.

- An inertial frame is the set of coordinates one uses to observe the universe at a particular velocity.

- Velocity is the combination of speed and direction. When either of these changes (acceleration), then one's inertial frame has also changed.

- All observers in the same inertial frame will agree on spatial and temporal measurements.

2. There is no such thing as invariant time or distance.

- Invariant means unchanging when switching between inertial frames.

- Newtonian relativity fails because a consequence of assuming invariant (absolute) time and space means that electromagnetic waves propogate at a velocity that depends on the observer's inertial frame.

- As a direct consequence of the invariant speed of light, time and space cannot ever, under any circumstance, be absolute.

3. Observers in different inertial frames CAN agree on measurements of time and space, given that they perform the correct transformation to translate one observer's measurements made in their inertial frame (coordinate set) to the set of coordinates used by the second observer to make measurements.

- The Lorentz transformation supersedes the more primitive (and more intuitive) Galilean transformation, as the Galilean transformation fails at extreme scales.

- Here there be maths. What is important to remember is that all of this can be boiled down to perspective. Just as a vanishing point (or points) in a painting provides the coordinate system in which to realistically portray objects of the same height at different depths of view, and by moving those points, one can portray the same scene accurately from a different perspective, the Lorentz transformation allows one observer to transform his observations of time and space into a portrait that another observer in a different inertial frame (perspective) would agree with.

4. The inertial frame of the universe "at rest" can be defined by using the Cosmic Microwave Background Radiation.

- Without getting into too much off-topic complications, once we subtract out anisotropy (not sameness) caused by interaction of the CMBR with matter on its way from the surface of last scattering to us, we can, through red-shift on one side and blue shift on the other, determine our velocity through spacetime relative to the inertial frame of the universe at rest. (NOTE: I would appreciate a link to an amateur friendly site that explains this.)

- Our galactic group's velocity relative to the CMBR is about 600 km/s and our solar system's velocity relative to the CMBR is about 370 km/s.

- The CMBR is not a "priveledged frame" with "absolute time". It is an inertial frame like any other. However, it is very useful, as by making a measurement of the temperature of the CMBR and by noting the dipole anisotropy of the CMBR that results from moving relative to it, an observer can place himself in a universally agreed upon time and space.

 

 

 

Surely a signal is instantaneous if, and only if, the age of the universe, in the event it is sent from and in the event it is recieved in, is the same... Then we speak of the events, in a natural way, as being simultaneous.

What we see lies always in the past since rays takes their time to reach us,except when a signal is instant so the picture of someone sending an instant signal arrives after the signal itself.

 

Should that make us believe that the signal really arrived before it actually was sent!? That Is To Confuse The Event Of Sending The Signal With The Event Of Seeing The Instant Signal Being Sent!

 

Hands on Hearts... How many of you has done this mistake? Or spoken "lightly" as if you had?

 

I ask because such a mistake seems to be made in the Max/Maxine experiment, and

(i suspect) in any experiment where instant signals are found in the past.

 

You are relying on intuition, and your intuition has been formed at a scale in which Newtonian relativity seems obvious. Your notion of instant and simultaneous betray this fact. The "mistake" you claim is exactly the only view consistent with Special Relativity. That you claim otherwise shows that you are still thinking in terms of absolute time. I have already posted two (in my opinion very good) youtube clips that show why your view is inconsistent in a universe with invariant speed of light. It is late, I must break for now. If required, I will try to explain simultaniety again later.

[CraigD]

A nicely written, helpful, and informative post, JM! :thumbs_up

 

I found the part about the CMBR dipole anisotropy,

4. The inertial frame of the universe "at rest" can be defined by using the Cosmic Microwave Background Radiation.

- Without getting into too much off-topic complications, once we subtract out anisotropy (not sameness) caused by interaction of the CMBR with matter on its way from the surface of last scattering to us, we can, through red-shift on one side and blue shift on the other, determine our velocity through spacetime relative to the inertial frame of the universe at rest. (NOTE: I would appreciate a link to an amateur friendly site that explains this.)

- Our galactic group's velocity relative to the CMBR is about 600 km/s and our solar system's velocity relative to the CMBR is about 370 km/s.

- The CMBR is not a "priveledged frame" with "absolute time". It is an inertial frame like any other. However, it is very useful, as by making a measurement of the temperature of the CMBR and by noting the dipole anisotropy of the CMBR that results from moving relative to it, an observer can place himself in a universally agreed upon time and space.

but would add some caveats and cautions about reading too much cosmological significance into it.

 

It’s tempting to use our local group’s motion relative the CMB and Hubble’s law to calculate our distance from the center of mass of the universe – a question that’s intrigued me since, as a youngster, I first read about big bang cosmology. The calculation’s pretty simple:

 

[math]\frac{V_{LG}}{H_0} \dot= \frac{627 \,\mbox{km/s}}{22.6 \,\mbox{(km/s)/Mly)}} \dot= 27.7 \,\mbox{Mly}[/math]

 

A fairly thrilling result, as it places “the center of the universe” only about 10 times as far away as our nearest neighbor galaxy Andromeda, well within our supercluster in the opposite direction (http://galactic coordinates Long: 276° Lat: +30°) from Virgo! :)

 

However, according to the cosmic expansion feature of the best current cosmological theory, this calculation doesn’t actually give a distance to the center of mass of the universe. Rather, [imath]V_{LG}[/imath] is just a measurement of its motion relative to the average motion of local matter at the end of the “photon epoch”, about 377,000 years after the big bang, when the universe became transparent. This is still pretty cool data and interpretation, but not as cool as the naive “center of the universe” interpretation of it. :(

[CraigD]

Ive checked the chapters and there are no new contents in Special relativity I was not aware of before ...

My problem lies in using and ,to some extent, understanding the Mathematics involved.

Being aware of the literature of subject within a discipline – in this case special relativity within the discipline of mathematical physics – doesn’t automatically confer an understanding of the subject. As I think you’re aware, Sigurd, understanding physics has a prerequisite of understanding math – though I suspect you overestimate the difficulty of acquiring it; an introductory, working grasp of classical physics including special relativity requires only the 4 basic arithmetic operations (+, -, *, /), the square root operations, and related basic plane Euclidean geometry. They are beautifully simple and elegant theoretical systems, and, in my experience, pleasant to use in a way similar to singing and playing a musical instrument.

 

The first [using the mathematics involved] needs practise, practise "wastes" time...

Alas, as we lack means of instantly acquiring knowledge like Neo does in The Matrix (eg: the famous

), practice is the only way to acquire it. As for it wasting time, I submit that attempting tasks one lacks the practice-acquired knowledge to complete successfully wastes far more time and effort.

 

It hurts to be considered an Ignoramus of Physics! ...

Your pain might be alleviated by considering what I think is an important distinction among disciplines.

 

Math and Science are subject where “knowing is doing”. Even if they were expert in the history of the people and cultures who developed, say, algebra, and its glyphs, terms, and definitions, few would say they knew[/i] algebra unless they were able to do algebra. In other disciplines, this requirement isn’t present. For example, an expert in classical music might not be able to play any musical instrument, compose, or even competently sight read music, but still be said by musicians and non-musicians to “know classical music”.

 

… (Especially by Ignoramuses of Reasoning.)

I don’t believe most people acquainted with Special Relativity, or with the general acquaintance with the mathematical physics in which SR is stated, are “Ignoramuses of Reasoning”. Learning more formal disciplines don’t forever bar you from reasoning informally!

[sigurdV]

Hi!

In returning to internet I find JMJones0424 to be honest, courageous and informative (Your view on simultanity and the Max/Maxine experiments interests me.), and I welcome him and all such opponents! (But please give me time to read and think before I answer.)

 

 

Looking back on my first entry i suppose I could have been more careful:

 

I should perhaps have pointed out that Im aware that clocks in different frames of acceleration does not tick with the same speed, thereby refuting Newtons definition of "Absolute Time". But I havent yet seen a proof that no acceptable definition of the disrespected concept exists,therefore I proposed that the Age of Our Universe (Or rather the distance in time to the Big Bang.)could be an equivalent. I mean...no matter what we do we dont change the age of you know what? Travelling with high speed makes it seem as the Universe ages faster, but that is an illusion caused by the fact that our clocks are ticking more slowly... its not the U that is accelerating in time its us who are decelerating. OR??

 

CraigD thinks it wont take me too long to master Lorentz Transformations, and I think he might be right... Why havent I already? ...Well the truth is that I think the theory has a suspicious foundation in having a definition of simultanity a text book author (Rindler) will not claim is a "proper" definition ,instead he calls it "Practical"! And leaves it at that!!

 

If I were reading part of the bible I wouldnt bother...

But discovering a circular definition in the foundation of Special Relativity doesnt result in the tranquility I will need to return to math studies of some 40 years ago.

 

The circularity can be removed by accepting some other definition of "simultanity" in the right part of the definition, but in denying there to be such a definition I find the friends of Albert Einstein sawing off the branch they are sitting on!

 

And also they find no fault in the Max/Maxine argument...

 

Suppose Max and Maxine started from the same point( now the midpoint of the segment MaxMaxine) then their calendars should read the same. If Max in his 1990 sees a picture of Maxines calendars saying 1988, then Maxine should in her 1990 see Max calendar saying 1988.

Any instant signal between them from one 1990 will surely be recieved in the other 1990 not 1988.And at least two years will pass before anyone of them will see the other receive or send the instant signal! The only way Max in 1990could see an instant signal of his reaching Maxine in 1988 would be if he had sent it in 1988.

 

Lacking calculating ability i still think i can show my point: Let the twins repeat the experiment sending an instant signal every 24 hours. The first signal will to all practical purposes arrive simultanesly with the picture of it being sent and the picture of it received. As time passes the distance between them and their speed will increase (with amounts decided at the beginning of the experiment)and it will be noted that the signal arrives before the pictures of it being sent or received... I think the formulas in Special Relativity enables Max and Maxine to calculate in advance every time what their clocks (and what the clock in their received pictures of their twin)will show the instant Max sends his signal BUT (I predict): never will the signal be noted by Max or Maxine to arrive before or after it is sent!

 

PS I dont recall giving any definite examples of ignoramuses of reason...Did I? Actually i dont expect them (if they exist)to survive long in here. Perhaps I get a little paranoid sometimes.

[sigurdV]

 

 

 

This definition is only circular, I think, when expressed in a natural language manner like this, and parsed very a-contextually. The sentence does reduce to a circular “<noun> are simultaneous if and only if <verb> simultaneously”, but this analysis fails to appreciate the key distinction between the physical referents of the two occurrences of the “simultaneous” lexeme: the first refers to events that a separated by a large distance, the second to events separated by a small distance, important distinctions in the mechanics of special relativity.

 

Do you mean that there are TWO concepts of simultanety in Special Relativity? One for events separated by large distances, and another for events separated by small distances?

 

Ive checked my text book but nowhere is there a definition of simultanity for small distances! And neither did I find the border between small and large discussed...

 

Also: That the first occurrence is a noun and the second a verb is not necessary , the second ocurrence can be replaced with: ...the arrival of the light signals at the midpoint is simultaneous. Then simultanity is honestly expressed the same way in both sides.

(That it was not done so in the first place can be taken as a sign that someone has something to hide.)

 

 

And: The part of your explanation where the expression "natural language" occurs is difficult to understand. The definition is indeed expressed in natural language, but not by me ...its by W. Rindler Ph.D. Is there an alternative way of expressing the definition that Rindler was not aware of?

 

Perhaps i misunderstand, but it seems above as if you try to simultaneously admit and deny the circularity of the definition.

[JMJones0424]

I should perhaps have pointed out that Im aware that clocks in different frames of acceleration does not tick with the same speed, thereby refuting Newtons definition of "Absolute Time". But I havent yet seen a proof that no acceptable definition of the disrespected concept exists,therefore I proposed that the Age of Our Universe (Or rather the distance in time to the Big Bang.)could be an equivalent. I mean...no matter what we do we dont change the age of you know what? Travelling with high speed makes it seem as the Universe ages faster, but that is an illusion caused by the fact that our clocks are ticking more slowly... its not the U that is accelerating in time its us who are decelerating.

 

You are still stuck. No two observers will agree on the precise age of the universe unless they are in the same inertial frame. If you define simultaneity to be when two events are equidistant in time to the big bang, you have not specified what frame you are making the temporal measurements in. One could choose the rest frame of the universe as that frame. However, if you maintain that simultaneous events in that frame are simultaneous in all frames, then anyone (us) traveling at a non-zero velocity relative to that frame would find themselves in a peculiar position. We would need to first check our speed and direction and use that to determine how much time we must observe passing between two events in order to declare them as being simultaneous.

 

Perhaps you will see your error more clearly if you construct some spacetime diagrams to illustrate.

[sigurdV]

Hi!

 

Ive been vacationing, hoping some rest would clarify things... but the basics of relativity still mystifies me, take for instance the Michelson Morley experiment:

 

Its essential principle was to send a light-signal from a source to a mirror and back, noting the total time taken, doing it in the supposed direction of the ether stream (resulting in t1) and at ninety degrees to it (resulting in t2).

 

But... Time eventually gained/lost in travelling to the mirror was lost/gained when the signal was returning from the mirror, the effects cancelling each other out, so the result should be: t1=t2, no matter what relative speed to an ether there may be.

 

To make the experiment measure anything, perhaps one should only measure the time taken in one direction.

 

Its nice to hear that there really is a rest frame of our universe that can be distinguished from other inertial frames. And that if we determine our speed and direction relative it then we can have simultaneity... whats peculiar about that?

 

Also: Thanks for the spacetime diagrams, they are interesting and might be helpful!

[JMJones0424]

Its nice to hear that there really is a rest frame of our universe that can be distinguished from other inertial frames. And that if we determine our speed and direction relative it then we can have simultaneity... whats peculiar about that?

 

Also: Thanks for the spacetime diagrams, they are interesting and might be helpful!

The italicized portion of your quote is false. As has been stated and shown, simultaneity is frame dependent. Spacetime diagrams aren't just pretty lines to look at. The link I provided clearly and simply explains how to use basic math to transform between inertial frames. If you wish to continue your fantasy of universal invariant time, then I won't waste any more of my time here. Both time and the speed of light cannot be invariant.

[sigurdV]

We would need to first check our speed and direction and use that to determine how much time we must observe passing between two events in order to declare them as being simultaneous.

 

Above is what I intended the italicised portion of mine to express...

If that was false then perhaps the preceeding part of a universal rest frame was false as well?

 

The continual insistence of using the mindset of Special Relativity as a necessary prerequisition for acquiring the said mindset reminds me more of theology than science.

 

It must be possible for say , Newton , to learn about relativity step by step with no use of faith in relativity... Right?

I think N would accept the measuring of the speed of light... but the next step eludes me:)

 

Both position in space and time is supposed to be relative, but where are the satisfying arguments? In circular definitions and experimental **** ups?

 

Is it really too much to ask for convincing demonstrations given of:

 

1 The relativity of space.

2 The relativity of time.

 

Before introduction of advanced concepts of the theory?