The Speed of Light is Not Constant

[brucep]

Write4U



Yet we have the observed fact that the more matter and energy in local spacetime the slower time goes(dilation), to the point that time stops at both the Event Horizon of a Black Hole and at lightspeed. From that extreme point time flows faster with LESS matter and energy. When you get to very low(but not zero)energy levels time flows it's fastest. So what mechanism then turns time off when at it's fastest just because that last little erg disappears? And what mechanism causes time to go from non-existence to full speed when a single Quantum of energy arrives? Your paradigm does not fit the facts. Rather than non-existence in empty space, time runs at it's fastest rate in the absence of dilating mass or energy. So it exists independent of whether mass does, even though it is affected when it does.

Time is a dimension every bit as valid as one of any other distance. You can see the past(in fact that is all you can see, simultaneity is an illusion cause by the very short distance in time of the things close to you, they too are in the past), it is a distance in this Universe. We do not see the Universe as it is in the present(even the sun is 8 minutes in your past), we see it as it was in increasing distances into the past. Time is very real and is a characteristic of spacetime, which is what our Universe is. Matter and energy affect spacetime, but like a water balloon, there is a container(spacetime)and a contained(energy and matter), and while the water inside the balloon distorts the balloon, it is not the same thing as the balloon. Nor does it create the wall of the balloon by needing to be contained.

Here's an exercise to show how spacetime is one thing. Describe how you would return to Earth's surface from a trip to Mars and back. You know the Earth's orbit, but if you guess wrong you could end up 186 million miles away from your target on the other side of that orbit. So how would you designate the position you need to reach? You must specify where the Earth will be at the position in it's orbit. In other words, it takes not only coordinates in the three dimensions of space, but also one of time. That's Earth's position in 4D spacetime. Time is measured by motion or change, but it is not created by motion or change, they only slow it down.



Are you laboring under the delusion that "meaning" is a concern of the Universe? Just because we cannot measure something does not mean it ceases to exist. Time is, whether you can extract meaning from it or not. Motion let's us extract meaning from time, just like a well let's you extract water from the depths. Do you think the water is not still there when you are not near a well? That's the logic you are trying to apply to time. Time is not a characteristic of matter, it is a characteristic of the Universe itself.

Grumpy

It's interesting how such natural phenomena, time and matter, are modeled using physics. Based on what I can gather from personal experience [good scientific tool], + physics models, time 'is' natural phenomena. It's pretty simple for me: the rate at which time and all other natural phenomena change. The 'rate being natural phenomena' just like everything else in the universe. No matter what you call it you can't eliminate it from this universe. It even makes the physics easier to model. Go figure. When you eliminate the curvature component [the term for matter] from the metric you get the Minkowski metric. We can model an expanding universe which is 'dust free' but you can't model an expanding universe without some reference to 'rate' of change.

 

[Grumpy]

Aqueous Id

That being said, there is evidence that spacetime is perpetually being created, which begins with Hubble's observations of the expanding universe.

Created is not the word I would use, rather the existing metric is being expanded(by momentum and, evidently, Dark Energy). The rising of a loaf of bread is not because more dough is being added, but it gets bigger anyway. There is more spacetime either way, but creation is a loaded concept that really only applies to our Universe at the Big Bang(whatever it's cause). Otherwise I agree with your assessment.

Grumpy

 

[brucep]

"Change" is not a very good word since we talk about gradients, which are changes in a parameter over any dimension in general, not just time. Thus the temperature of ocean water changes over depth rather than time, air pressure changes with altitude, or the strength of a field changes with distance between emitter and detector.


That being said, there is evidence that spacetime is perpetually being created, which begins with Hubble's observations of the expanding universe. That is, space and time are both being created, it would seem, without any other cause. This is consistent with the way we describe changes in any parameter q with respect to time: dq/dt, or with respect to space: dq/dx + dq/dy + dq/dz, or both. It's therefore more logical to say that any change in any parameter is always referenced to a change along the axis of some dimension.


Not necessarily, since energy can exist as light (photons) which literally illuminate space and time.


More to the point there could be no matter without space.


That won't account for the perpetuation of time because matter can't be created anymore. Nor is there any observation to conclude other wise. What's observed is that space is being created. So the best answer is probably just to say space and time are being created out of the Big Bang itself, that we are still Banging, just in a highly condensed epoch already shaped by billions of years of cosmic evolution.

Very informative post Id.

 

[forrest noble]

I maintain that time emerges (is created) with change. Without matter "time" would be a meaningless term and without time there would (could) be no matter. Both come into existence at the same "instance", i.e. a physical event (change) which becomes "historically fixed" at a spacetime coordinate.

I agree with your statement relating to motion of matter defining time and that matter particles must posses motion, I believe in the form of angular momentum, to exist. I do not believe time came into existence or that it was infinite in times past either. Most people think it must have been one way or the other. But that's a different subject that could be discussed in a more topic-related thread. Of course like the definition of time, there is also no consensus view as to its origin other than a BB origin.

cheers

 

[forrest noble]

PhysBang,

my posting # 634

Rutherford was my hero in this regard when he said: If you can't explain your physics to a barmaid it's probably not very good physics. "If you can't explain your physics to a bartender it's probably no damn good." "If you can't explain your research to the cleaning lady, it's not worth doing." and "if you can't explain your research in layman's terms, you probably don't understand it yourself."

Your answer:

This is too high a bar to ask of someone in a very technical job.

Yes, probably so. My suggestion would be for one to spend adequate time phrasing explanations in his mind and on paper if one desires the most clarity concerning explanations; then give it his best shot when there is a need or desire to explain it to others. That's all one can do

Rutherford was well into his 30's when Special Relativity was proposed, in his 40's when General Relativity was proposed, and in his 50's concerning the beginnings of Quantum Mechanics. Explanations of classical physics (Rutherford's time) were/are far easier for most people than explanations of modern physics. If one could give a simple explanation of Quantum Theory (Mechanics) today , for instance, whether the explanation was ultimately right or wrong, there would be very few that would agree with the explanation. This is because there are four major versions of the theory and all are quite different from each other. There are also dozens of lesser known versions and explanations of Quantum Theory. On the other hand the math system involved (Quantum Mechanics) is based upon statistics and a long history of observation by which many of the equations now-used were derived, but this is not the theory. This is a system of mathematical mechanics, for predictive purposes, that few would disagree with.

 

[brucep]

PhysBang,

my posting # 634


Your answer:


Yes, probably so. My suggestion would be for one to spend adequate time phrasing explanations in his mind and on paper if one desires the most clarity concerning explanations; then give it his best shot when there is a need or desire to explain it to others. That's all one can do

Rutherford was well into his 30's when Special Relativity was proposed, in his 40's when General Relativity was proposed, and in his 50's concerning the beginnings of Quantum Mechanics. Explanations of classical physics (Rutherford's time) were/are far easier for most people than explanations of modern physics. If one could give a simple explanation of Quantum Theory (Mechanics) today , for instance, whether the explanation was ultimately right or wrong, there would be very few that would agree with the explanation. This is because there are four major versions of the theory and all are quite different from each other. There are also dozens of lesser known versions and explanations of Quantum Theory. On the other hand the math system involved (Quantum Mechanics) is based upon statistics and a long history of observation by which many of the equations now-used were derived, but this is not the theory. This is a system of mathematical mechanics, for predictive purposes, that few would disagree with.

This is complete nonsense.

"This is because there are four major versions of the theory and all are quite different from each other. There are also dozens of lesser known versions and explanations of Quantum Theory."

If you're talking about the pedagogical interpretations of QM they all recover the theory in detail. They're not completely different versions of the theory of quantum mechanics. There's only one version of QM.

 

[forrest noble]

This is complete nonsense.

"This is because there are four major versions of the theory and all are quite different from each other. There are also dozens of lesser known versions and explanations of Quantum Theory."

If you're talking about the pedagogical interpretations of QM they all recover the theory in detail. They're not completely different versions of the theory of quantum mechanics. There's only one version of QM.

As I said above, there is first the mathematical system of mechanics (Quantum Mechanics) that nearly all agree upon. Then there is theory to explain why the mathematical system would be valid. Here I am making a distinction between theory and the mathematical application of it. Some, like myself, prefer a distinction between quantum mechanics, where there is little disagreement concerning the predictive system, and the theories which try to explain its validity, where there is much disagreement.

 

[brucep]

As I said above, there is first the mathematical system of mechanics (Quantum Mechanics) that nearly all agree upon. Then there is theory to explain why the mathematical system would be valid. Here I am making a distinction between theory and the mathematical application of it. Some, like myself, prefer a distinction between quantum mechanics, where there is little disagreement concerning the predictive system, and the theories which try to explain its validity, where there is much disagreement.

You made a distinction between pedagogical interpretations like the Copenhagen and Transactional interpretations without any rigor [such as an entry clarifying what you meant by 'different versions' of QM]. You made it sound like QM has different outcomes depending which version is used. That's why 'I say stuff' to add some rigor to the nonsense that gets tossed all over this forum. You should pay attention to the possible interpretations of what you're going to write down and apply rigor to assure it's interpreted the way you mean.

 

[Aqueous Id]

Aqueous Id

Created is not the word I would use, rather the existing metric is being expanded(by momentum and, evidently, Dark Energy). The rising of a loaf of bread is not because more dough is being added, but it gets bigger anyway. There is more spacetime either way, but creation is a loaded concept that really only applies to our Universe at the Big Bang(whatever it's cause). Otherwise I agree with your assessment.

Grumpy

You are right about inflation best being explained simply as an expansion along any world line. The discussion about the state of the universe at the moment of the Big Bang is one of considerable speculation. Although it's remarkable that physics has arrived at a timeline for primordial evolution of the cosmos down to the Planck epoch, it's hard to imagine that anything more than speculation will ever come out of all attempts to define the conditions at t=0. It's entirely uncanny. Anyone can speculate that there is either an endpoint on the timeline at t=0, or that it's conceptually like plotting f(t) = 1/t as t approaches zero from the right. The former suggests that the "something from nothing" arises out of a state of timelessness and spacelessness whereas the latter suggests the divergence from a pole (singularity) at t = 0 which is a curve of infinite extent, meaning "it took forever" to get to that first Planck epoch. But the "zero endpoint" case is also highly problematic: it suggests that there is actually a state of existence which is actually one of actual timelessness and spacelessness. Following that logic, it leads to the inference that the "creation event" is perpetual. That is, the timeless state never advances through real time, meaning it's perpetually frozen, meaning it coincides with each instance of real time. And it's spaceless, which is the condition "at" the edge of the universe and "at" every event horizon and "at" every point mass--conceivably a gluon or something smaller . . . something which "actually occupies space" (creates a pole or singularity) even though this kind of thinking breaks down at the quantum scale.

Continuing this last idea, there is another inference, namely, that the "zero endpoint" case presents a reality in which the primordial singularity is "ever present" "at" this spaceless "place" (nonplace really) "where" all mass actually coincides and lives forever. And it necessarily coincides there with the "eternal singularity". Alternatively we can equate all mass with the singularity and extrapolate just about any wild and crazy idea thereafter---from retrocausality to just about anything that makes no sense and has no physical evidence to support it. That's just nature of speculation, and the reason people smarter than me don't even dwell on it.

What exactly does the expansion of all world lines even mean? Inquiring minds want to know. Hence lots of wild and crazy ideas come to mind, which, unfortunately, simply have little or no basis in evidence.

And that's why it's better, as you note, to simply refer to inflation as the expansion of world lines.

We now return control of your screens to you. :geek:

 

[Aqueous Id]

As I said above, there is first the mathematical system of mechanics (Quantum Mechanics) that nearly all agree upon. Then there is theory to explain why the mathematical system would be valid. Here I am making a distinction between theory and the mathematical application of it. Some, like myself, prefer a distinction between quantum mechanics, where there is little disagreement concerning the predictive system, and the theories which try to explain its validity, where there is much disagreement.

I frequently hear this line of reasoning from people who don't actually do any math at all. Math is organic. It's arithmetic. It's the logic of proofs and theorems. It's spatial and visual. It's quantitative and relational. It's operational and functional. It's systematic and algorithmic. It's stochastic and deterministic. It's bounded and unbounded, divergent, convergent and so on and so on. Unfortunately for folks lost to basic math, there is no benchmark to help decipher what the funny looking symbols mean. And that makes it not only cryptic to them, but unable to convey that composite sense of what that organic knowledge actually amounts to.

What stuck in my mind when I read your post was Then there is theory to explain why the mathematical system would be valid. It's entirely the other way around. The math explaining some piece of evidence is simply the tool for collating facts and crystallizing them into some essential principle. The idea is to be able to make generalizations based on specific facts in evidence. The theory isn't there to explain the math; the math is there to explain the evidence. And that is all that theory really is.

 

[PhysBang]

So time is not more dilate(slower)on the surface of the Earth than it is far from mass(careful, both have been accurately measured, IE they have been observed)?

But that is not the same as time slowing to a stop. Very much not the same.

Time slows to a stop for anything at lightspeed, it's been accurately measured in the LHC that at very close to lightspeed particles travel much further than their known lifetimes at non-relativistic speeds would allow and the closer to lightspeed the slower their time goes, the shower of particles from a Cosmic ray does reach the ground(it shouldn't).

As far as I can tell, things with mass can never reach lightspeed. You appear to be applying an extrapolation here and calling that extrapolation an observation.

Time dilation due to speed is well evidenced. So is time dilation due to mass. So how is it you think those things aren't true?

I never wrote that I think those things aren't true, so why are you saying that I think those things aren't true?

I don't know where you got the idea that physicists have just been sitting on their hands for the last one hundred years,

Are you fucking kidding me?

Read my fucking posts.

 

[paddoboy]

Ahh, some healthy debate here!
From my position, after a 60 minute surf,followed by a shit, shave, shower and shampoo, and in regards to time stopping.......
After much ridiculious claims by Farsight and undefined, the way I see it is as follows.....
Time does stop at the EH of a BH from an outside FoR. The thing is though, we never get to see that happening, as anything we see approaching the EH, is gradually redshifted further and further along the spectrum until it literally disappears from the capabilities of our'scope.
We can then get a better infrared 'scope, and we will continue to see anything approaching the EH to be even further shifted along the spectrum until it disappears from that 'scopes capabilities.
But we never ever quite see it reaching the EH and consequently never ever quite see time absolutely stopping.

From a local FoR though, anything or anybody will cross the EH without anything extraordinary happening [ignoring tidal gravitational effects]

More to the point there could be no matter without space.
.

And no time or anything else....
In fact the BB would not have banged!

 

[paddoboy]

And as far as I know, from what I have learnt from a well respected SR/GR expert on another forum, light/photons in there own local FoR, would be able to traverse the Universe in an instant....Time at "c" from a local FoR, ceases to have any meaning.

Which then as I understand, re-enforces the speed of light is constant debate.
Anything with mass can never reach "c", and anything with no rest mass, must always travel at "c"


Any errors, alterations and/or corrections to the last two posts?

 

[forrest noble]

Aqueous Id,

The theory isn't there to explain the math.

Re: Quantum Mechanics and Theory

The math has been derived from data and corroborated based upon over 80 years of observation of quantitative results. The theories are there to explain observations like the double-slit experiment, quantum entanglement, wave collapse, quantum tunneling, etc., events and observations that require words to explain their logic or lack thereof. The math/physics, like any theory, is needed for calculating quantitative results of experiments and observations, for predicting possibilities of events, etc.

 

[Grumpy]

PhysBang

But that is not the same as time slowing to a stop. Very much not the same.

It indicates the slope of the graph, and if you extend it to lightspeed time indeed does stop. The point being that time dilation is a result of speed, it is mathematically logrhythmically, inversely proportional to speed and the endpoint of that slope is lightspeed. It has been measured in the colliders at close(in the LHC very close)to lightspeed, the effects are real. Time slows to a stop at lightspeed and under a certain level of acceleration that is only encountered at a BH's Event Horizon. The inverse is also true, time passes at it's fastest rate where spacetime has the least energy in it.

As far as I can tell, things with mass can never reach lightspeed. You appear to be applying an extrapolation here and calling that extrapolation an observation.

Yet we can get very close to lightspeed if we start with protons or nuclei of heavy elements. And while no mass can reach lightspeed, time dilation at just less than lightspeed is very high, the particles travel distances of several feet when their known non-relativistic lifetimes only allow fractions of a foot at lightspeed. Their time is slowed down, so they travel further before decaying. Each of those particles is a clock with a known time of existence. In Nature the same thing happens in Cosmic Ray collisions with the top of the atmosphere, the particles in the resulting shower also have a known lifetime, we've created and studied them for years in labs at non-relativistic speeds, they are nifty little clocks. According to their known lifetimes they shouldn't even make it down to the Stratosphere from those Cosmic Ray collisions at near lightspeed, but we pick them up just fine at ground level. That's because their time is going slower, it is dilated by their motion, and that allows them the time needed to reach the ground. The slope of the graph of time dilation is well established even if the endpoint(lightspeed)is not reachable. And that is confirmed by observation from orbital speeds to just under lightspeed and in and out of our Earth's gravity field.

why are you saying that I think those things aren't true?

Because you said...

Neither of these is an observation. Neither is true. Time never slows down to nothing, as far as we can tell and time certainly does not slow down to a stop for GR.

Time certainly can slow to a stop for GR. If gravity dilates time(and it does), and if higher gravity dilates time even more(and it does)at some point on the graph gravity will reach a point where it stops time. With speed that point is lightspeed, with acceleration/gravity that point is the EH of a BH. And there are BHs everywhere in the Universe.

Read my fucking posts.

I already do, and I disagree with some of the things you said. And my posts reflect those dissagreements.

Grumpy

 

[Trippy]

And while no mass can reach lightspeed, time dilation at just less than lightspeed is very high, the particles travel distances of several feet when their known non-relativistic lifetimes only allow fractions of a foot at lightspeed. Their time is slowed down, so they travel further before decaying. Each of those particles is a clock with a known time of existence. In Nature the same thing happens in Cosmic Ray collisions with the top of the atmosphere, the particles in the resulting shower also have a known lifetime, we've created and studied them for years in labs at non-relativistic speeds, they are nifty little clocks. According to their known lifetimes they shouldn't even make it down to the Stratosphere from those Cosmic Ray collisions at near lightspeed, but we pick them up just fine at ground level. That's because their time is going slower, it is dilated by their motion, and that allows them the time needed to reach the ground. The slope of the graph of time dilation is well established even if the endpoint(lightspeed)is not reachable. And that is confirmed by observation from orbital speeds to just under lightspeed and in and out of our Earth's gravity field.

My recollection is that this is only true in the lab frame. In the particle frame the half life is the same as if the particle was at rest, however, a particle frame observer would measure lab frame rulers as being contracted.

 

[Grumpy]

Trippy

My recollection is that this is only true in the lab frame. In the particle frame the half life is the same as if the particle was at rest, however, a particle frame observer would measure lab frame rulers as being contracted.

True, from inside their frame it looks like we are the dilated ones. This Relativity stuff is not easy to understand unless you make such distinctions plainly. We are all a little biased toward our own frame's view of reality. The spray of particles from Cosmic Ray collisions see the distance to the ground as being much shorter and themselves lasting for the same time and speed through that shorter distance from the ground they see in their frame. We see them lasting a longer time at the same speed over the greater distance above the ground we see in our frame. And by see I mean that is the reality they see, these are real physical effects and both frame's perspectives are equally valid. While their real speed is less than lightspeed, it is a significant percentage of lightspeed and both frames see the same relative speed(it is the speed relative to each other)between upper atmosphere and the ground. Again, relative speed remains constant, but everything else changes to keep speed constant in both frames.

Grumpy

 

[paddoboy]

""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
Muon Experiment

The measurement of the flux of muons at the Earth's surface produced an early dilemma because many more are detected than would be expected, based on their short half-life of 1.56 microseconds. This is a good example of the application of relativistic time dilation to explain the increased particle range for high-speed particles.

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/muon.html
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

 

[Trippy]

""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
Muon Experiment

The measurement of the flux of muons at the Earth's surface produced an early dilemma because many more are detected than would be expected, based on their short half-life of 1.56 microseconds. This is a good example of the application of relativistic time dilation to explain the increased particle range for high-speed particles.

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/muon.html
""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

Now go to Relativistic muon based observer

 

[paddoboy]

Now go to Relativistic muon based observer

Isn't that supporting what you and Grumpy have said?

And both FoR's agree on the final outcome.