Why is there a universal speed limit, c, and why is it what it is?

[Dale]

I disagree that it is a common misunderstanding.

Then prove me wrong by showing me how you can use the scientific method to answer questions of some other form.

 

[CosmicVoyager]

Then prove me wrong by showing me how you can use the scientific method to answer questions of some other form.

I think the problem may be that the people I am referring to are claiming that questions are not scientific when they are. That is, that the answer could be a "mathematical model X correctly predicting the observation Y in experiment Z to within experimental error", but that current equations already do that. In other words, there is a mechanism inside the ball, which we could develop a mathematical model for that would predict observations, but because a model already exists that predicts without a complete description of all structure, they have no interest in doing so. That is sufficient for practical applications, but people want to fully understand the structure of the universe.

Advice to people asking question: Many contributors here have an allergic reaction to the word "why". Instead say something such as "How is it that...". I have discovered that by actually simply avoiding using the word "why" while still asking essentially the same question, you get better responses, and avoid the negative reponses to "why" that we are so annoyed with.

 

[Dale]

I think the problem may be that the people I am referring to are claiming that questions are not scientific when they are. That is, that the answer could be a "mathematical model X correctly predicting the observation Y in experiment Z to within experimental error", but that current equations already do that.

That is fine. If you or pip1974 can re-phrase the question into that form then I would heartily agree that the question is scientific.

In other words, there is a mechanism inside the ball, which we could develop a mathematical model for that would predict observations, but because a model already exists that predicts without a complete description of all structure, they have no interest in doing so. That is sufficient for practical applications, but people want to fully understand the structure of the universe.

What you are suggesting here is that people use a more complicated mathematical model than is necessary to explain the data. I do not, in principle, have any problem with that. It does violate Occham's razor, but it is not contrary to the scientific method.

Advice to people asking question: May contributors here have an allergic reaction to the word "why". Instead say something such as "How is it that...". I have discovered that by actually simply avoiding using the word "why" while still asking essentially the same question, you get better responses, and avoid the negative reponses to "why" that we are so annoyed with.

Excellent advice.

 

[CosmicVoyager]

TWhat you are suggesting here is that people use a more complicated mathematical model than is necessary to explain the data. I do not, in principle, have any problem with that. It does violate Occham's razor, but it is not contrary to the scientific method.

I anticipated bringing up Occam's razor, and almost included that. LOL I don't think it is the simplest answer because questions still remain. Why is it moving that way? What is inside the ball? And I don't think there will be an infinite regression of why questions. I think a point can be reached where it finally all makes sense. Where the picture is complete. Where apparent contradictions are resolved rather than just being adjusted for.David Bowman in 2010: "You see, it's all very clear to me now. The whole thing. It's wonderful."

 

[Dale]

And I don't think there will be an infinite regression of why questions.

You obviously don't have any four-year-old kids.

 

[nitsuj]

CosmicVoyager "Advice to people asking question: May contributors here have an allergic reaction to the word "why". Instead say something such as "How is it that...". I have discovered that by actually simply avoiding using the word "why" while still asking essentially the same question, you get better responses, and avoid the negative reponses to "why" that we are so annoyed with."

I couldn't agree with you more Cosmic. It seems the issue is the one answering cannot (i hope this is a word) contextualize a response.

Questions like "What makes the sun hot"
seems to be a world apart from "Why is the sun hot", for some people. (Note:dalespam I don't literaly mean one world distance between the two questions, that's merely a figure of speech, such as the question why)

Kids, perfect example. With no use of the scientifc method, your kids will grow up to develope an "understanding" of things of allsorts (and probably,thanks to you, better then most). I am sure observing your kids you see their understanding of the world around them "evolves". There are prerequisites in this evolution. When the question "where do babies come from" comes up, I am sure you will provide an edited explination. One that your kid is satisfied with and is congruent with their understanding in general.

To sum it up, a question, one human to another (providing context for you) is the same as asking "help me understand xyz so that it fits with my current understanding in general".

It's no wonder that after 18+ years of developing an understading (whether conscious or not) of time, that when one crosses paths with the idea of relativity many more questions come up, as we rework our "general understanding" so that everything fits together in a way we are comfortable with.

Perhaps, dalespam, that is why you have no issue with there being a universal speed limit, because you have seen so many equations and graphs that you have "seen" how there is a universal speed limit. You have a "feel" for this speed limit. It fits into your "general understanding", quite simply you accept it.

Your "why" question has been answered.

 

[Dale]

It seems the issue is the one answering cannot (i hope this is a word) contextualize a response.

I believe that my responses have "properly contextualized" the question that I responded to:

we can explain and describe almost everything we can observe. But what's missing is the 'why' bit.

The above question is not akin to your "what makes the sun hot" vs "why is the sun hot" example. I think that you are the one having trouble "properly contextualizing" the question. He is specifically rejecting answers of the form that science can provide. If you disagree then kindly re-phrase the question in the form I have mentioned above, because I am obviously too stupid to see the rephrasing which is so clear to you.

 

[jtbell]

I anticipated bringing up Occam's razor, and almost included that. LOL I don't think it is the simplest answer because questions still remain. Why is it moving that way? What is inside the ball? And I don't think there will be an infinite regression of why questions. I think a point can be reached where it finally all makes sense. Where the picture is complete. Where apparent contradictions are resolved rather than just being adjusted for.

I think it's legitimate to hope for something like that. The problem is, what do you do if there are competing theories which all "explain" a currently "incomplete" theory, but there is no way to distinguish between them experimentally, even in principle? We actually have that situation in quantum mechanics right now, with its various interpretations.

 

[Dmitry67]

Meanwhile, I will attempt to give an example of scientific "WHY"

Q: Why CKM mixing angles are not = 0?
A: Because if they were equal 0, there won't be any difference between matter and antimatter. After the annnihilation, there would be just light, no matter, and no conscious observers.

 

[nitsuj]

DaleSpam "The above question is not akin to your "what makes the sun hot" vs "why is the sun hot" example. I think that you are the one having trouble "properly contextualizing" the question. He is specifically rejecting answers of the form that science can provide. If you disagree then kindly re-phrase the question in the form I have mentioned above, because I am obviously too stupid to see the rephrasing which is so clear to you."

I don't know what the question was but if "He is specifically rejecting answers of the form that science can provide" that should help you "contextualize" your response, no?

Don't ever pose me with "If you disagree then kindly re-phrase the question in the form I have mentioned above, because I am obviously too stupid to see the rephrasing which is so clear to you" it's insulting to both of us. You couldn't convience me, despite you trying, that you are "stupid". In fact I think the issue is somewhat the opposite, you need to stop being so "smart".

 

[pip1974]

Dmitry67 and DaleSpam. Scientific method is a tool, a method in fact, that allows us to answer questions about the natural world.
If someone asked me why the sky is blue, I would be able to understand their question and give them an answer based on my knowledge of science. It's a shame you claim you wouldn't be able to do the same thing.
I wonder what certain people's motives are for trying to answer questions here. Seems to be a rather egotistical activity to me, in which the prime motive is to demonstrate knowledge rather than share it.
Here's a challenge. Suppose someone were to ask "why can't a spaceship go faster than the speed of light", I bet I could give a really good answere that would satisfy most inquisitive people, and I would be able to pitch it at the appropriate level without trying to show off how clever I am. I bet you couldn't.

 

[Calrid]

As usual in these arguments its about semantics and isn't really important. Some people are restricting the language to a more pure form of science and some are not, it's all basically correct though, it just depends on how you phrase it. We all know the difference between why does the Universe exist at all, philosophy, and why is the sky blue. It would be couched in a proof in science, such as: I can show how scattering in an a atmosphere favours some wavelengths, with x experiment, that would show y results, or, we could say the reason why it is blue is because of the above because we already accept as an axiom that the reasoning is solid and is self evident.

The fact remains science at the research level does not deal in whys so much as hows. It only deals in whys when the facts are taken for granted. One is pure science the other is science explanation. Why do men walk on two legs is a valid question only if it is appropriately asked and answered. How did men come to walk on two legs would be the basis of research, why wouldn't unless it was a weaker more philosophical form of science, like anthropology and even then it would probably not be couched in too many whys if it was a research paper.

 

[nitsuj]

Calrid It's not simply semantics, and it is really important that people don't piss on other people's pursuit of "why" something is simply because an f-ing graph doesn't translate to their accepting it as the answer "why".

If someone has their head so far into the scientific method that they cannot translate it back to the "real" world, then the purpose of the scientific method in the "real" world is lost.

 

[Calrid]

Calrid It's not simply semantics, and it is really important that people don't piss on other people's pursuit of "why" something is simply because an f-ing graph doesn't translate to their accepting it as the answer "why".

Oookay, we'll have to agree to differ. I think it is semantics you don't.

Semantics is a vast part of philosophical debate that has impact on all areas of reason, it is highly important. I did not mean to demean it but I think that overall it is unimportant in this context because of the way ideas are formulated, or theories, the more solid science. Just meant to say that it is a matter of connotation, how you use language and in which way becomes deeply significant in logic and reason. Ultimately though just be careful you are not just saying the same thing with different words. We can dispense with whys in science at certain levels: the cutting edge for example.

Why is more often a philosophical question, how is more often in the remit of science. That's not to say they don't have a utility in both, I just question if there is all that much of a difference in how and why in certain ways of saying things and in certain fields.

 

[nitsuj]

I'm convinced.

I admit poor understanding of the meaning (and in turn importance) of semantics.

"I did not mean to demean..." clarifies it for me, and I retract my claws :)

Calrid, your second post almost has me understanding dalespam's point of view. A seemingly impossible task just a few posts ago.

 

[Dale]

I don't know what the question was but if "He is specifically rejecting answers of the form that science can provide" that should help you "contextualize" your response, no?

I quoted it directly in post 77, to which you were responding. I re-post it here again for your convenience.

we can explain and describe almost everything we can observe. But what's missing is the 'why' bit.

Note, that you can click on the little arrow to be taken back to the post and see it in context.

I don't think that I am in any way distorting pip1974's intention with that sentence, nor being artificially obtuse, nor "improperly contextualizing". He apparently knows and understands the mathematical model and its predictions. What he specifically wants in that quote is the reason why the model works, and that is something that science cannot ever answer.

 

[Dale]

If someone asked me why the sky is blue, I would be able to understand their question and give them an answer based on my knowledge of science.

That is a good example. What would your answer be to the question "Why is the sky blue?" And I will remind you of your own comment which sparked this debate:

we can explain and describe almost everything we can observe. But what's missing is the 'why' bit.

So by your own criteria that we are discussing, an explanation and a description (i.e. a mathematical model) is not sufficient to answer "why".

 

[harrylin]

This is a very common misunderstanding. Science is fundamentally incapable of addressing "why" questions. Science can only answer questions of the following form: "Does the mathematical model X correctly predict the observation Y in experiment Z to within experimental error?". Even if the answer is "yes" the scientific method does not and cannot answer the question "why" the model works.

That's much too pessimistic IMHO!
No explanation is never certain of course, and in general no explanation is perfect, but science does help to increase understanding. For example, if you were right, Newton's work on mechanics was a failure*. However, most people would agree that he did giver deeper insight in the "why" of such things as Kepler's orbits: instead of just a magical formula, it started to make sense.

As a matter of fact I would have abandoned science a long time ago if it did not deliver on this point.

* But how we are to collect the true motions from their causes, effects, and apparent differences; and, vice versa, how from the motions, either true or apparent, we may come to the knowledge of their causes and effects, shall be explained more at large in the following tract. For to this end it was that I composed it.

 

[pip1974]

That last bit you quoted was specifically in reference to the original question. You don't need to remind me. I would explain that the sky appears to be blue because of refraction. I could point the questioner to the relevant sources if they need more detail.
If asked the original posters question, I'd say "I don't know, I really don't think anyone knows why that is the case but someday if a unifying theory is found a clearer picture may emerge". That's what I'd say. I wouldn't start having a go at the questioner for not putting questions in the right form, and would not persist in a pointless semantic debate with someone who just said they understood the question. That's it from me.

 

[harrylin]

[..] They want to know about the mechanism inside. And if you can come up with a design of the mechanism that works, then it will also be accurately predicting observations. [..]

Obviously. Now people come up with different possible answers - "the" design that works is an illusion, usually several could work, with the existing knowledge. I would still agree that that is more satisfying than "we don't know" or "that question can't be answered", which probably is a facade for "we are clueless".

And we gave you several possible answers (models) in this thread; you can freely choose the one you like or the one you think is more plausible or the one that for you looks the simplest.

 

[GrayGhost]

I am asking why there is a "universal velocity c."

Why is there a c? Why is there a speed limit to the universe? Why is there a limit to how quickly a cause can follow an effect at distance? Why is there a "causality constant"?

What is(are) the limiting factor(s) that make it what is? The speed limit is a consequence of what? Is what we know to be the speed limit the result of measurements? Or is it a logical problem that can be figured out in a thought experiment?

CosmicVoyager,

All very good questions :)

To be frank, no one (anywhere) has answered these questions to date in any satisfactory way. Nor have I. When one does, a nobel prize sits begging.

One fellow here brought up geometry as a fundamental root of this. That's a reasonable and fundamental statement I suppose, but it doesn't answer the question.

Here's my opinion on the matter ...

Relativity theory suggests we all travel thru the continuum at the equivalent of c. This suggests that what we measure as "the relative velocity between material entity" is the result of unparallel speed-c velocity vectors thru the continuum. If parallel, then they are at rest with each other.

The next question is this ... Why would we travel thru spacetime at c?

I would suggest that the answer here may relate to "spacetime expansion". It could be that light does not move at all, that it only appears to move, because we move thru spacetime at c. This is no different than each of 2 inertial starships assuming themself the stationary and the other in motion, and both being correct. It's all relative. Anywho, food for thought.

GrayGhost

 

[nitsuj]

DaleSpam RE: post 86.

I didn't recognized it as a question because it is not a...nvm.

I misunderstood you dalespam, seems you have clarity beyond understanding. :)

 

[nitsuj]

CosmicVoyager,

All very good questions :)

To be frank, no one (anywhere) has answered these questions to date in any satisfactory way. When you do, a nobel prize sits begging.

One fellow here brought up geometry as a fundamental root of this. That's a reasonable and fundamental statement I suppose, but it doesn't answer the question.

Here's my opinion on the matter ...

Relativity theory suggests we all travel thru the continuum at the equivalent of c. This suggests that what we measure as "the relative motion between material entity" is the result of unparallel speed-c vlocities thru the continuum. If parallel, then they are at rest with each other.

The next questions is this ... Why would we travel thru spacetime at c?

I would suggest that the answer here may relate to "spacetime expansion". It could be that light does not move at all, that it only appears to move, because we move thru spacetime at c. This is no different than each of 2 inertial starships assuming themself the stationary and the other in motion, and both being correct. It's all relative. Anywho, food for thought.

GrayGhost

I kinda agree,
If time stops at C, and space is time, then is it not true at C you are in the same space as you were previously so nothing changes, ie no time? RETORICAL.

It makes sense to me. Objects cannot exist in the same space another object occupies, if it could wouldn't that mean there is no time between them? RETORICAL.

 

[Huttate]

Keep thinking. Remember this spacetime malarky very nearly sent Albert over the edge, and they never Nobel'd him coz they thought it wacky.

It takes a new pair of eyes - and probably a young pair if history is any guide - to see it from a different angle.

But do keep thinking, otherwise you are just repeating the words of the wise and we all know they are not fundamentally right in all aspects of the universe in which we live.

 

[GrayGhost]

If time stops at C, and space is time, then is it not true at C you are in the same space as you were previously so nothing changes, ie no time?

It makes sense to me. Objects cannot exist in the same space another object occupies, if it could wouldn't that mean there is no time between them?.

I'm not quite sure how this applies to what I stated, however no 2 material entities can occupy the same space. Even if an observer could magically accelerate to relative c, he would not co-occupy space with other-normal-speed-heavenly-bodies. If he ever does, he collides, and that would be a huge mistake on his behalf (and the other's).

GrayGhost

 

[nitsuj]

Both your idea and mine share spacetime itself as moving, you didn't derive that from what I said, I'll try agian.

I didn't even remotely say that something traveling at C would "co-occupy" space with a slower moving object. In fact I feel poisoned having been associated with that remark.

The second RETORICAL question you replied to was to isolate the idea of C being the reason for time stopping.

(the glass of milk on my counter will go bad fairly soon, maybe by tommorow, my chocolate milk mix won't, it has a much longer shelf life. Now if I put this chocolate milk mix into the milk, time between them is now irrelevant, my chocolate milk mix that is in the milk will spoil lock step with the milk. that's another way to very loosley describe what i was saying about occupying the same space and there being no time between them. as far as the spacetime I can see those two items now occupy the same spacetime, if you notice the beverage is sweet and nutritious at the same time, miraculous, making healthy food pallatable by eliminating the time between the experience of it and tastey food lol, chocolate milk time traveling in action, okay I've gone too far now :)

 

[bobc2]

...In other words, there is a mechanism inside the ball, which we could develop a mathematical model for that would predict observations, but because a model already exists that predicts without a complete description of all structure, they have no interest in doing so. That is sufficient for practical applications, but people want to fully understand the structure of the universe.

CosmicVoyager, while I certainly appreciate the concept DaleSpam has communicated to us, I really seriously tried to present a picture of a mechanism ("inside the ball") resulting in a limiting value for the speed of an object. I really presented this picture as a serious candidate for answering the question, "Why does speed have a limiting speed, namely the speed of light?" I'll present the graphics again because I think it is a reasonable picture of the situation. I could explain this in more detail, but it would take an unreasonable amount of space here. The picture should not be dismissed as just graphics.

To appreciate the picture a person of course is going to have to develop some concept of a 4-dimensional universe and be able to interpret a spacetime diagram in that context. I can do a tutorial in a different thread if need be (or folks can google "spacetime diagram"). My diagrams are intended to be fairly literal picture models of observers moving at relativistic speeds and "living" in a squence of 3-D cross-sections of a 4-D universe. If one really wants to pursue your "why" question, they should first pursue an understanding of spacetime diagrams if they do not already have a grasp of special relativity.

First of all, just this one fact alone, namely that the X1 axis rotates symmetrically toward the X4 axis for increasing speeds, is adequate to explain why all observers measure the same speed for light. You should be able to see directly in all of the pictures below of different observers with different velocities that the ratio of X1 to X4 is the same for each one of those pictures. This is a definite answer to the question about same light speed for all observers. (It's as good a "Why" answer as you would get about the blue sky.)

Again, the sequence of 4-D pictures below (X2 and X3 supressed) are a serious attempt at demonstrating why there must be a limiting speed. Once understanding this, an even more burning question of physical reality arises: WHY does an observer's 3-D cross-section view (the X1 axis) of the 4-D universe continually rotate so as to eventually converge on the 4th dimension (X4 axis)? This seems to be the more fundamental question, because again, that magical rotation leads to the limiting value (X1 and X4 axes converging in the limit).

In other words, if the model below, as implied by special relativity, is accepted as a working model, we could then proceed to the next "why" question: "Why does the X1 axis rotate?" (Note that in Newton's model of the universe, the X1 axis never rotates--but then experiments have shown that Newton's model does not work at relativistic speeds).

 

[Dale]

I didn't recognized it as a question because it is not a...nvm.

D'oh! I quoted it a half-dozen times and never noticed that it wasn't actually a question.

 

[nitsuj]

At least it wasn't your point. And I retract my comment from the same post "I misunderstood you dalespam, seems you have clarity beyond understanding. :) " .

 

[Dale]

For example, if you were right, Newton's work on mechanics was a failure*.

Why on Earth would you say that? He came up with an amazingly simple mathematical model that is still in use more than 3 centuries later due to its simplicity and accuracy.

I don't think that it is "pessimistic" to understand the limitations of the scientific method. It is not a magical crystal ball, nor the mythical oracle, it has limitations and it is good to understand those limitations. There is nothing pessimistic nor optimistic in that understanding, it just is an understanding of the nature of a valuable tool.

 

[nitsuj]

bobc2 "WHY does an observer's 3-D cross-section view (the X1 axis) of the 4-D universe continually rotate so as to eventually converge on the 4th dimension (X4 axis)?"

That is some writing worthy of publishing. Just tickles my brain lol

Some annimation of that happening would be wicked.

 

[CosmicVoyager]

@bobc2

I should have replied the first time to say thanks and that I find it difficult to convert the graph into visualizing what is happening in 3D. What I would like to see is an animation of a photon in a 3D grid, or an illustration with 2D representing 3D and 3D representing time. You seem to be saying the universe is changing shape, which it obviously cannot be doing since it would require the universe to simultaneously have different shapes for every particle moving at a different speed. That is a direct contradiction.

 

[bobc2]

@bobc2

I should have replied the first time to say thanks and that I find it difficult to convert the graph into visualizing what is happening in 3D. What I would like to see is an animation of a photon in a 3D grid, or an illustration with 2D representing 3D and 3D representing time.

Let me think about that and see if I can figure out a way to do a better job of communicating.

You seem to be saying the universe is changing shape, which it obviously cannot be doing since it would require the universe to simultaneously have different shapes for every particle moving at a different speed. That is a direct contradiction.

I think I fully agree with you. But, I must be cardful that we are talking about the same universe. When I think of the universe not changing shape, I'm picturing the 4-dimensional universe. But, with the so-called "block universe" model the observers experience a continuous sequence of new cross-sections of the 4-dimensional universe. And this does mean that observers moving at different speeds would, at any instant of time, be "living" in different 3-D universes. And that would certainly be contradictory if it were not for a model that feature a 4-dimensional universe populated with 4-dimensional objects (including the 4-dimensional bodies of the observers). I really hesitate to carry the description much further for a number of reasons, but can if you wish. But the 4-D picture is pretty much as shown in the earlier sketches. After a while I'll throw up one more graphic to make the picture a little more complete.

 

[nitsuj]

Let me think about that and see if I can figure out a way to do a better job of communicating.

I think dalespam and bobc2 should become friends. :)

 

[CosmicVoyager]

I think I fully agree with you. But, I must be cardful that we are talking about the same universe. When I think of the universe not changing shape, I'm picturing the 4-dimensional universe. But, with the so-called "block universe" model the observers experience a continuous sequence of new cross-sections of the 4-dimensional universe. And this does mean that observers moving at different speeds would, at any instant of time, be "living" in different 3-D universes. And that would certainly be contradictory if it were not for a model that feature a 4-dimensional universe populated with 4-dimensional objects (including the 4-dimensional bodies of the observers)..

If time is one of those dimensions,and each particle is a cross section, wouldn't that require 5 dimensions? Because with only 4 the fourth has to be either the sequence of cross sections which would still require an additional dimension for time, or the fourth be time and no cross sections for each particle?