Why is the speed of light the same relative to any frame of reference?

[Rationalise]

Why??
What makes it the only constant in the universe?

 

[EL]

Basically no one knows why the laws of nature look like they do. Physics just describes them...
But c is not the only constant. (Others are h-bar, G...)

 

[pmb_phy]

Originally posted by EL
Basically no one knows why the laws of nature look like they do. Physics just describes them...
But c is not the only constant. (Others are h-bar, G...)

Actually if it was proven that Maxwell's equations were correct and that the photon's proper mass was zero then the constancy of light could be derived from the principle of relativity and Maxwell's equations

 

[EL]

Ok, but that just leads us to the next question...why do Maxwell´s equations look like they do?
You will always end up at something unexplainable "in the bottom"...(at least no one has yet been able to start from anything else to build up a theory from)

 

[russ_watters]

You're going to end up in an infinite "why" loop with these questions. There really isn't a good absolute answer here. The three most common are: "They just are," "God made them that way," and "if they were any different, we couldn't exist to observe them."

As you can see, "why?" is more philosophical than scientific. It can be interesting to think about/discuss, but it isn't really all that scientifically relevant.

 

[EL]

That´s my point...

 

[LURCH]

.

But c is not the only constant. (Others are h-bar, G...)

I think he meant, "only constant speed...".


I tend to use hyperdimensional reasoning to make lightspeed's frame-independance more palitable. If you can accept the fact that speed and direction are two different ways of looking at a single property, then you can make the "absolute speed" of light (a speed which is the same to all observers) an absolute direction, which is at the same angle from any path. This helps me tie lightspeed to the fourth dimension; time.

 

[ahrkron]

I agree with EL and Russ in that, ultimately, there are things in the universe that "just are", regardless of how much they make our neural circuitry feel "comfortable".

However, there's a couple of comments that may help you accommodate your intuition around a constant speed of light.

First (probably close to what Lurch said), when you measure the magnitude of the four-dimensional "speed" of any object, it turns out to be c always; how we measure it to move with respect to us is somewhat of an accident.

Second, I just want to emphasize that, counter-intuitive as it sounds, a constant speed of light is perfectly compatible with all experimental evidence to date.

Finally, the answer to your question is somewhat buried among the generality of maxwell eqns: from them, you can derive the speed of a wave regardless of the speed of its source.

 

[Adam]

You're talking about the motion of energy through matter. In any given medium, the EM energy can move at a given speed. Why would the speed at which the energy can migrate through a given material change simply because you are running left instead of walking right?

 

[russ_watters]

Originally posted by ahrkron
I agree with EL and Russ in that, ultimately, there are things in the universe that "just are", regardless of how much they make our neural circuitry feel "comfortable".

To take this a step further, some people seek the answers to some unanswerable questions in religion, but unfortunately there are always unanswerable questions, even in religion. The 'why?' of many things can be answered by citing God, but what about 'why?' questions on God himself?

 

[EL]

Originally posted by russ_watters
To take this a step further, some people seek the answers to some unanswerable questions in religion, but unfortunately there are always unanswerable questions, even in religion.

At least our way of logic thinking cannot get around this problem...maybe we´re just not enough smart...

 

[ahrkron]

My take on it is that this is a limitation of all representation systems, and that intelligence and reason are unavoidably based on representations, implying that no matter how "smart" any species becomes, it will always have unanswerable questions.

 

[EL]

Originally posted by ahrkron
My take on it is that this is a limitation of all representation systems, and that intelligence and reason are unavoidably based on representations, implying that no matter how "smart" any species becomes, it will always have unanswerable questions.

Yes, but you are saying that from our logical point of wiev. What seems reasonable to us must not be the truth...
(Of course even my own reasoning is based on logic thinking, which makes this whole philosophical discussion paradoxial.)
However I think it´s dangerous to believe that our small brains are capable of determining what is possible to know and what is not.
But I agree that in the way humans are thinking now, we will always have unanswerable questions, no matter how smart we are...
Hope you got me...

(Sorry for leaving the field of physics)

 

[mhernan]

Speed o lite? Constant?

Most publication use the Michelson-Morley experiment as a talking point and they refer casyually to the "null" result, implying there was no data showing light affected by the so-called aether drag. However, MM experimental results were not null, just approximately 1/20 of the 'expected' drift througth the aether. In the 1920 and after, Dayton Miller performed hundreds od MM tests which resulted ibn a finding of about 1/20 iof the 'expected'. So we have to assume the calculated value by the then current prevailing views in physics were correct in their assesment of the Earth's velocity through space if we are to place any faith in the experimental results of MM..
On a slightly different angle the famous 'eclipse' experiments ofd 1919measuring the pull of mass on light from distant stars in 1919 was hailed as a huge success and Eisnstein was an immediately star. The eclipse experiments were "questionabley accurate". Where the calculated focal resolution was 2-3 arc seconds, the paper on the eclipse experiments claimed resolution of hundreths of a millimeter.
Einstein lauded the resolution of .01" in his Relativity book. This number came from comparing exposures of stars on photographic paper taken months apart and then overlaid and compared!
Is the velocity of light constant in all directions?
Yes?
No?
Prove it.

 

[Haelfix]

Fortunately, we don't have to build interforometers anymore when analyzing special relativity. Instead we can look in modern particle accelerators, where everything is relativistic and calculable to 11 significant digits.

Any deviation in exact lorentz symmetry would output huge corrections to our results. We don't see it, ergo we still think special relativity is right.

 

[ahrkron]

Another piece of evidence for SR comes in the fact of the electricity bill for accelerators.

The higher the speed, the higher the mass (as measured in the lab's frame), which means that you need to have a higher magnetic field to keep your protons on track. All this numbers (from the mass to the measured field to the amount in dollars needed to keep all working) agree with SR.

 

[Nereid]

Here's a summary of tests of SR (there may be a better, more up-to-date summary; if any reader has found one, please let us know).

The 1919 eclipse observations were indeed 'marginal'; I would hope that no reviewer today would have agreed to its publication. Fortunately, a great many other observations have been made, involving both one-way (e.g. quasars) and two-way (e.g. Voyager on Mars, Cassini) signals.

I've not found anything better than http://relativity.livingreviews.org/Articles/lrr-2001-4/ as a summary of GR tests.

 

[Terry Giblin]

Is the speed of light traveling through a pure uniform rain droplet within a cloud, the same in every direction?

Is it therefore not logical to assume that the speed of light traveling through uniform 3-Dimensional droplet within an 11 Dimensional super cloud will also be the same in every direction?

 

[Nereid]

Originally posted by Terry Giblin
Is the speed of light traveling through a pure uniform rain droplet within a cloud, the same in every direction?

Is it therefore not logical to assume that the speed of light traveling through uniform 3-Dimensional droplet within an 11 Dimensional super cloud will also be the same in every direction?

I didn't know that GR had been formulated in terms of 'an 11 Dimensional super cloud', I thought that was super-gravity, or String Theory, or M-Theory. I am also unaware of any experimental results which indicate a need for any such theories; GR has passed all its tests with flying colours.

You may want to read some of the threads in Strings, Branes & LQG, in the Physics sub-forum.

 

[Terry Giblin]

Hi Nereid,

You are correct for point out that General Relativity, did not need additional space dimensions, but it Special Relativity (SR) would work very well without considering the time dimension and GR would not work within the frame of SR until we add the dimension of mass in for form of electrons and six additional quarks.

Where would quantum mechanics be without the electron and six quarks, in a 4-D spacetime inside a 10 or 11 dimensions super cloud.

The superstring theory describes the photon and electrons in 4-D spacetime and not forgetting the 6 quarks and the M-theory describes the cloud.

Newton, General Relativity, quantum mechanics, c,..., are all simple subsets within the cloud.

 

[DW]

Originally posted by ahrkron
Another piece of evidence for SR comes in the fact of the electricity bill for accelerators.

The higher the speed, the higher the mass (as measured in the lab's frame), which means that you need to have a higher magnetic field to keep your protons on track. All this numbers (from the mass to the measured field to the amount in dollars needed to keep all working) agree with SR.

Actually the experiments are in agreement with the special relativistic law of motion according to which the mass does not change with speed. It is the time derivatives in the law of motion that are dilating. The charge follows a path described by
$$\frac{q}{c}\eta _{\mu}_{\nu}\frac{dx^\mu}{d\tau}F^{\nu \lambda} = m\frac{d^{2}x^\lambda}{d\tau ^2}$$ and according to this special relativistic law of motion the mass m does not change with speed.

 

[Hurkyl]

sees their rational professionalism as superior to intuition, reason and simplicity

They don't.

However, to some people (yourself included, it seems):

intuition = what I learned from parents / TV / elementary school
reason = logic (and illogic) that supports what I think
simplicity = little to no deviation from what I think it should be

and they have grounds to think "rational professionalism" is superior to these.

 

[mhernan]

quote:
Mhernan stated in an earlier post:
sees their rational professionalism as superior to intuition, reason and simplicity.
[/QUOTE]


To which Hurky replied, somewhat indignantly:

They don't.

However, to some people (yourself included, it seems):

intuition = what I learned from parents / TV / elementary school
reason = logic (and illogic) that supports what I think
simplicity = little to no deviation from what I think it should be

and they have grounds to think "rational professionalism" is superior to these

You didn't quite get it, but I do see a a superior professional with his hand dutifuly raised in identifying himself.

Intuition is the flooding of consciousness with ideas and thoughts bubbling from the deep and unswimmed sea of my depths.

Rationalizations as in the feakish use of mathematical models that are of value only to the mathematicians: See "interference amplitude", "relativity" and "AIDS" for soem ice berg tips.

Simplicity as when the light falls on the darkness caused by unilateral complexity: "The Doctor knows best". Take most of the mathematical models out of physics and an immediate advancement of science occurs. The mathematics used modernly to an excess was designed and developed for business needs.In a world where events happen sequentially, on all levels, why are models ignoring just this obvious triviality? Now\ the mathmaticians tell us through the quantum mechanical fog, that "reality", the "base reality of the quantum world" is mere "potentiality", "we can never know the essence of nature". Feynman in his textbook "Lectures on Physics", no less, utters at least 100 times (I quit counting) in the three volumes, how much "quantum mechanics is a mystery:, "we just don't know,", "science has given up", yet we clothe his nmemory in the garb of yet another god.

You said, "they don't". I say "they do". Are you one of them? Do you believe your rational professionalism is superior to say, one practicing voodoo?

 

[Hurkyl]

I'm something much worse. I'm a mathematician.


The problem with arguing that something must be correct because it is "intuitive" is that you are the only person in the world who has the same intuition as you do. And even then, your intuition will change as you learn new things. (Assuming you care to)

The other problem is that intuition is gained from experience. If you have little to no experience with something, your intuition is likely to be very poor. And be honest with yourself, you have little to no experience dealing with facts about velocities over 100,000 MPH and objects smaller than a nanometer in diameter.

Thus, it is extremely arrogant of you to think your intuition about such things has any sort of reliability. And it is this arrogance that earns you (and others like you) the "attitude" you get from others.


I'm willing to admit that I have little to no intuition about such things. Until you do too (or demonstrate that your intuition really is accurate), you will be forever a crackpot.

 

[mhernan]

Hurkyl replied to mhernan as

I'm something much worse. I'm a mathematician.


The problem with arguing that something must be correct because it is "intuitive" is that you are the only person in the world who has the same intuition as you do. And even then, your intuition will change as you learn new things. (Assuming you care to)

The other problem is that intuition is gained from experience. If you have little to no experience with something, your intuition is likely to be very poor. And be honest with yourself, you have little to no experience dealing with facts about velocities over 100,000 MPH and objects smaller than a nanometer in diameter.

Thus, it is extremely arrogant of you to think your intuition about such things has any sort of reliability. And it is this arrogance that earns you (and others like you) the "attitude" you get from others.


I'm willing to admit that I have little to no intuition about such things. Until you do too (or demonstrate that your intuition really is accurate), you will be forever a crackpot.

Mhernan replies to Hurkyl

I do not read my paper as claiming intuiton as the "above all" in mental processes. And no I am not the only person in the world with similar intuitions. And there you go making this vast summation of what I and the rest of the world may or may not be engaged in. Is that an automatic integrating machine I am sure you refer to as a mind that I hear clicking all the way to Arizona?

I made the point that my "intuition" came from the depths of my inward mental and [spiritual] self. Ever heard the words, "Eurecka!"

I haven't engaged in experiments where particles are moving at 100,000 mph, which is only .000015 the speed of light. My acceleration experiments were llimited to 50kv proton accelerations through single crystals of gold. What is the particle separation of gold atoms in a single crustal lattice? Is it in the nanometer range? What about your dealing with reality, ever perform a physics experiment?

But a mathematician now, one who doesn't need any freaking reality to clog their cherished rational constructs must be something else!

There is so much gobbly gook out there foisted on an unwary public by mathematicians posing as scientists that it is bordering on corruption. In a discussion with a PhD Physics professor, expert in "spinor theory" (all math degrees) she was unable to discuss the most fundamntal concepts of Stern-Gerlach transition experiemtns. When she could see me readying my wit to "thrust home" she retreated with a, "that's not my specialty.". The results of SG transition experiments are fundamental to quantum theory, which I am sure you weren't aware. I won the argument with the spinor theorist because she crumble when having to consider some very basic and not all that complicated physical facts, but then what can you expect from a mathematician.

When a mathematician refers to me as a crackpot I get so emotionally high that the unbvelievablye sweetness of it makes me sob. Actually you are the first to make such a claim. I cannot see how I managed to make it this far to have this day my first in recgnition of "crackpt status".

You really should have read my note again. It is apparent that you have grossly over reacted, and somehow felt threatened by what I actually said. You claim ignorance of intuiton, yet are completely, and smugly, ready to condemn anyone claiming the personal talent of intuitive thought. What do you mean "demonstrate" my accuracy? You haven't the slightest idea of what I do with my mental faculties and the very last person on this Earth I will ever feel a need to "demonstrate accuracy" to is some childish mathematician who preaches from a confessed platform of complete, total and utter ignorance.
Thank you for your support.[zz)]

 

[selfAdjoint]

I made the point that my "intuition" came from the depths of my inward mental and [spiritual] self. Ever heard the words, "Eurecka!"

And you are the only person who had this Eureka moment. It means nothing to anybody else, and it isn't eveidence of anything but your internal brain states.

 

[mhernan]

The scourge of intuition in rational models.

Originally posted by selfAdjoint
I made the point that my "intuition" came from the depths of my inward mental and [spiritual] self. Ever heard the words, "Eurecka!"

And you are the only person who had this Eureka moment. It means nothing to anybody else, and it isn't eveidence of anything but your internal brain states.

Are we to throw out Cartesian systenms because Rene Descarte had a flash of insight, intuition that was the senminal event of his brillaint career?

Whatever you discard from myself, for any reason, or ill-reason, is your concern and your problem. It takes only the slightest intuitive grasp to observe the silliness of the statement regarding "internal brain states". First, one must prove, by some rational systematic activity, that intuition is a state of mind and formed in the brain and secondly, that there can ever be a systematic scrutiny of brain states that directly and causally relate to any specific "brain state" under scrutiny or otherwise.

Mssrs. Adjoint and Hurkyl are so very adamant in approaches that there can be no question of the sincerity which they profess and held so tightly by convictions. However, virtually everything mentioned has been nothing but personal opinion. There isn't any of this beautiful "science" that would elevate the statements over the 'intuition'.

Were I to make an intuitive value judgment here I would say that the contest has come down to "opinion vesus intuition". In case you've not had the opportunity to scan my aphorism below my signature, it says: Convictions are more dangerous enemies of truth tnan lies.

 

[Integral]

I believe that history itself is all the evidence needed to counter the intuition argument. Intuition was the basis of science until Galileo's time. It is clear that all meaningful advances in our understanding of the physical universe have come since the abandonment of intuition as the key to understanding the universe. It was only by careful application of the scientific method which allowed humans to begin to understand the non-intuitive features of the universe.

To claim that all must be intuitive is an example of ethnocentrism at its worst.

Convictions are more dangerous enemies of truth tnan lies.

Clearly you have no convitions when it comes to this matter.~^ [?]

 

[ahrkron]

Originally posted by mhernan
Are we to throw out Cartesian systenms because Rene Descarte had a flash of insight, intuition that was the senminal event of his brillaint career?

No, he is saying that "Eureka moments", although being nice personal experiences, need to be followed by a lot of detailed math work in order to produce anything in science.

As Integral and Hurkyl point out, intuition has not been a reliable guide since, at least, the beginning of last century. In order to develop a useful intuition for modern physics, you absolutely need to go through a lot of math; without it, intuition cannot help you understand what has been discovered and (extremely well) measured in physics in the last hundred years or so.

 

[russ_watters]

The thing I find most ironic about the anti-math arguments is that the "intuition" is usually Newtonian physics. Now, that's probably just because that's the only physics these guys ever learned, but the ironic part is that Newton was the original and quinticential physicist<->mathematician. He invented a whole new branch of math just to use it as a tool to solve his gravity equations! Dilbert would call that "synergy."

And before Newton, "intuition" told most people (anyone who knew physics then learned it from Aristotle) that big objects should fall faster than small ones. Legend has it that Tycho Brahe used to drop verious sized food on the floor at dinner parties to demonstrate this intuition wrong (much to the chagrin of the hosts).

And don't get me started on Aristotle: his intuition told him that a fly should have 4 legs like a table to be able to stand. No need to actually look at one when your intuition has it covered, right?

 

[Michael D. Sewell]

Yeah, and it only took 2000 years for us to figure out that Aristotle was wrong. I don't know about you, but it sure makes me proud to be a human! God save us all. -Mike

 

[mhernan]

Ahrkon stated

Originally posted by ahrkron
No, he is saying that "Eureka moments", although being nice personal experiences, need to be followed by a lot of detailed math work in order to produce anything in science.

As Integral and Hurkyl point out, intuition has not been a reliable guide since, at least, the beginning of last century. In order to develop a useful intuition for modern physics, you absolutely need to go through a lot of math; without it, intuition cannot help you understand what has been discovered and (extremely well) measured in physics in the last hundred years or so.

mhernan resdonds


To those who are following this thread please be aware that it was I who used the term "intuition" for which the process of intuition is being debated as to its value as a competent and useful activity on a level with modern science. At no instant have I assumed or intentionally , or otherwise, indicated that a "message" arrived at through intuition be treated in the same light as a physical observation. Even Descarte had a problem, other than his 'rush of insight' at an early age. He struggled with the question of truth being somehow related to 'rational mental processes'- I think therefore I am.

My use of intuition was intended as response to what I understood was a claim that "mathematics" was a process providing scientific information with informatioal integrity on the level of experimetnal and scientific observations.

Whatever the arguments may be, one way or the other, my use of the word intuition was then intended, and remains intended, to mean that intuition >= mathematics as as valuable scientific information in modeling of nature.

If any wish to struggle with "proof" arguments, proceed on. There is always the problem, however, analogous to religious debates where each side demands the other "prove" it in terms of the one demanding proof. That systems differing in basic formative assumptions, that they do not dovetail, is by iteself, insufficient to establish one or the other as exclusively competent.

Any claims that the mathematical formulation of quantum theory, for instance, as a competent model of Mother Nature, exceeding all which preceded QT, must prove the statement true in scientific terms. The mere utterance that A = B, after all, is no different that I = B', where I = intuition. And, most importantly, it is the rational scientific side of this discussion making all the claims that I is a useless activity. Your system demands scientific proof of statements, yet you are so casual in ommitting the essence of your precious system, proof.

So, in your own terms, gentlemen, Prove it.


mhernan

 

[Integral]

intuition >= mathematics

This is an apples and oranges argument. Without intuition there would be no advances in mathematics or science in general. Without the ability to record and accumulate information there would be no advances in mathematics or science in general. The knowledge of what has been done by others must guide the intuition to enable insight leading to new knowledge. Without the cumulative knowledge of generations intuition reinvents the wheel. Unfortunately there is no easy way, there in no intuition, which will provide access to the cumulative knowledge of generations. That cumulative knowledge must be learned by sweat and inspiration, as there is much in that cumulative knowledge which seems to defy logic. But when it is all put together, it is your sense of logic which must be redefined.

What so many who claim, math is unnecessary, fail to realize is that they are the short sighted ones. Those who have struggled with the concepts and learned to understand and use mathematical and scientific methods are at an advantage, simply because they have seen both sides. At some point in their life virtually every scientist and mathematician did NOT have these skills. They have seen life with and without the skills so are able to differentiate between the states of knowing and not knowing. Those who have never put forth the effort to learn these skills have no way of understanding the advantages gained.

Once again, the only proof required to demonstrate that more is required then intuition is history itself, when only intuition was used little or no significant advances in our understanding of the universe were made. When mathematics was developed to record and guide intuition things began to happen. Intuition is how the human mind makes leaps of knowledge, Math is how these leaps are guided, recorded and shared with others.

 

[chroot]

This thread really seems to belong more in the Philosophy of Science and Mathematics forum than it does here. So... I'm moving it.

- Warren

 

[einsteinian77]

Why??
What makes it the only constant in the universe?

Prior to the big bang everything was constant, so to ask the question why something is constant I think you need to look at what made the singularity change.