Time itself has a biased flow direction.

[przyk]

As I don´t think time has any properties I disagree. First, AFAIK "topology" is concerned only with shape and really just the connectivity of it not the sizes. (People and donuts have same doublely connected shape to a topologist.)

I'm specifically referring to the notion of a topological space, which is the basis for e.g. differential geometry. Time is universally modelled as a differentiable manifold or at least as part of one in physics, which among other things means it has topology associated with it.

Secondly, as I think you know from your later mention of the mixing of time and space coordinates when describing how events in one frame would be described in another frame, there is no special aspect of "simultanity" as you seem to assert.

There is, in spacetime, in the sense that physical interactions have a property of locality with respect to space and time. In e.g. Lagrange formulations of physical theories, the behaviour of particles and fields are always coupled to other particles or fields at the same place and time.

But what I was mainly referring to is something you wrote earlier, which is this idea that, at least sometimes, you can eliminate the t variable from the description of an evolving physical system (I think you used the example of two planets orbiting one another). But even if you do that, you're still left with an equation stating that certain positions of one planet are "associated" with different positions of another planet, which is essentially expressing an underlying concept of simultaneity, or distinct "time frames", or whatever you might want to call it.

Many things are the same in all frames. E.g. The topology of an object is the same for all frames and H2O freezes at 0 C in all, but lengths and time intervals say between two LED flashes, measure by local clocks also change (don´t agree) and can be simultaneous in only one frame. These difference are just in how one frame describes meter sticks and light flashes, of another frame, not real changes in one frame.

You've misunderstood what I said. Actually much of what you're saying here is exactly the point I'm making. According to special relativity, there is a symmetry in physics which means that there are a whole bunch of different time and distance measurement standards, related to each other by Lorentz or more generally Poincaré transformations, that are all "equally good" as one another, in the sense that the laws of physics take the same form in all of them and none of them have any special measurable properties. Because one reference frame's space and time coordinates are actually a mixture of other frame's space and time coordinates, I don't see how you could claim that time doesn't fundamentally exist while space does without breaking relativity at least in spirit. Suppose space exists and I parameterise it with an $$x$$ coordinate, and suppose time doesn't fundamentally exist but somehow emerges as a useful parameter which I call $$t$$. Then what the hell are $$x' \,=\, \gamma(x \,-\, vt)$$ and $$t' \,=\, \gamma(t \,-\, \frac{v}{c^{2}} x)$$?

Incidentally, regarding what you say in post #78, in general relativity it's the spacetime manifold, and not just space, that can curve.

 

[AlphaNumeric]

It's not pointless przyk, it's important. The wrong language and the wrong figures of speech can cause huge problems.

Hence the usefulness of formalising models using mathematics, it isn't open to arm wavey turns of phrase and metaphors. This is another example of why understanding the details of a model is important, not just reading other people's approximate analogies and metaphors. When are you going to realise this approach of yours, to rely on other people's wordy simplifications of models you don't understand the details of, is inherently flawed? If you bothered (or were capable, since I don't think you could even if you wanted to) to learn the formal details you'd be able to see precisely what the models say, not have to rely on 2nd (or 3rd or 5th or 10th) hand summaries from people who did learn it.

No, but what I don't want is a whole pile of negativity from you in response to I'm pleased to see a discussion on time that focusses on scientific evidence instead of wandering off into woo like time travel.

You're one to talk. You're incapable of discussing the details of, for instance, George Ellis's work or the details of Kip Thorne's work or even something you claim to be a world expert in, such as electromagnetism, because you are, for all intents and purposes, innumerate. You claim to be a world expert in electromagnetism but you cannot model any electromagnetic system, you cannot make quantitative predictions in it, all you can do is work by analogy, based on your flawed understanding of other people's summaries of the details of things you do not, cannot, understand. You have never been able to discuss the details, the quantitative models, from any area of physics and your own work utterly lacks any quantitative details (beyond blatant numerology you considered amazing, thus proving my point about being functionally innumerate). A proper discussion of 'the science' of, for instance, electromagnetism would be beyond you. Instead you'd attempt to talk in analogies and arm waving. For example, curl. You don't know the vector calculus which pertains to curl, you can only arm wave about how it's to do with rotation. You were previously schooled on various things to do with the electromagnetic field and curl by myself and if I remember correctly przyk. Likewise with curvature and Prometheus.

If you were put in a room with a bunch of physicists like przyk who were discussing the details of their work you would be incapable of contributing constructively to the details. Instead they'd have to translate it into approximate layperson for you, to even allow you to understand what they are saying. You have no idea what 'talking about the science' really involves, you have only forums and pop science reading material to go on.

No doubt you'll ignore this post and call it vitriolic but the repeated demonstration of how you fail to grasp details and are led astray by your reliance on layperson analogies shows my advice you try to learn the details is entirely accurate. Similarly the complete lack of any quantitative details in your own work renders is 'worse than string theory'. Not even not even wrong. Until you learn some basic calculus and make your claims more than furious arm waving you're going to continue along the road to nowhere your work (and I use that in a very vague way) is currently on. How many years now? 5? How's that going for you?

 

[Billy T]

I'm specifically referring to the notion of a topological space, which is the basis for e.g. differential geometry. Time is universally modelled as a differentiable manifold or at least as part of one in physics, which among other things means it has topology associated with it. ...
But what I was mainly referring to is something you wrote earlier, which is this idea that, at least sometimes, you can eliminate the t variable from the description of an evolving physical system (I think you used the example of two planets orbiting one another). But even if you do that, you're still left with an equation stating that certain positions of one planet are "associated" with different positions of another planet, which is essentially expressing an underlying concept of simultaneity, or distinct "time frames", or whatever you might want to call it. ...

Thanks for clarify your "topology" but I´m not qualified to go further in this with you.

As far as there still being an "association" of space positions after time has been eliminated form the conventional equation describing things, yes that goes directly to my point that time does not cause anything but cause and effect still operate. Crudely the egg mess on the floor was not caused by time "advancing" but by real things like gravity and the support under egg being removed.

In two different posts I have given at least four different properties of space, which I regard to be real. I asked for just one property of time, which I regard to be just a very convenient and conventionally used parameter in descriptive equations that sort of hides or separates cause from effect by giving the change as a function of time, as if advancing time caused the change. No one has told me any property of time, so I continue to hold this POV.

 

[RJBeery]

Hi guys.

It's hilarious and serious all at the same time.

For the serious part, it's the double standard that gets me. For instance, Mazulu ponders and tries to make experiments on his 'frequency-shifting' idea for possible manipulation of space to produce gravity effects, and he is called a 'crank' delusional fantasizer. But when a professional physicist writes reams and reams about 'time travel' fantasies in the face of known theoretical and practical limitations to such speculative notions, he still retains his 'professional' status and is not immediately called a 'crank' delusional fantasizer (as he should be if what is good for the goose is good for the gander). That is what rankles when reading rationalizations as to why one is legitimate and one is not.

For the hilarious part, I will just observe that it appears the reason why professionals still write reams of time travel speculation is because they have nothing better to do. By that I mean that the collection of partial theories (however practically useful they may be within their partial domains of applicability) have hit a brick wall where 'consistent unification' is concerned, and they themselves have plateaued in the cosmological 'explanations' which explain very little but merely hypothesize still about unknowns upon which the theories depend. In short, it seems that time travel exercises are just a 'holding pattern' while they wait for something big 'to break' that will finally make sense of all the disjointed and iffy assumptions/models of the universe to date. It's like 'escapism' for the frustrated professional who hasn't anything more to offer. To relieve stress/frustration of going nowhere, and to distract from the impotence of current approaches to the universal reality interpretations. The ordinary joe goes to the movies; the medico goes to a golf course to hit a little ball around; and some professional physicists sit and write about time travel fantasies. No problem with physicists relieving stress and distracting the public with these professional fantasies....except for that double standard I spoke about above, which treats their musings as 'legitimate' speculation while others doing their own speculation on what interests them are called 'cranks' for doing essentially the same sort of thing.


To whom it may concern: Nothing personal. Just making my objective observations on this aspect.

Still, it takes all kinds, even in the professional ranks.....double standards notwithstanding. End of opinionated rant.

Yeah I notice this quite a bit. The debate isn't based on what is said as much on who said it...

 

[przyk]

As far as there still being an "association" of space positions after time has been eliminated form the conventional equation describing things, yes that goes directly to my point that time does not cause anything but cause and effect still operate. Crudely the egg mess on the floor was not caused by time "advancing" but by real things like gravity and the support under egg being removed.

Well that's fine, but I'm not aware of anyone saying otherwise. Saying time doesn't cause anything and that it doesn't exist are two different things. Personally I think the best way to think about both space and time is as existing but being little more than a stage in which interesting physics can take place.

In two different posts I have given at least four different properties of space, which I regard to be real. I asked for just one property of time, which I regard to be just a very convenient and conventionally used parameter in descriptive equations that sort of hides or separates cause from effect by giving the change as a function of time, as if advancing time caused the change. No one has told me any property of time, so I continue to hold this POV.

I would argue that much about what you said about space could also be said about time:

Yes. It has serveral properties, two of which can be measured in the lab and do, just a Maxwell predicted, let you calculate the speed of light in vacuum from these lab measurements.

If you're referring to the so-called "permittivity of space" and "permeability of space", then those are the names of constants in Maxwell's theory of electromagnetism. Despite their names, I don't know why they should be associated with space in particular (as opposed to spacetime), and not just treated as constants in a theory.

Also electrons and positron pairs pop up in space [...]

Isn't "pop up in space" more a matter of suggestive language (it implies you're thinking in terms of looking at all of space while "advancing" through time) rather than a specific property of space? Personally I'd say the phenomenon doesn't treat space and time much differently from one another: electron-positron pairs are always created and annihilated together in the same place and at the same time. From a more abstract point of view you simply have an electron-positron pair that exists and has a small history in spacetime, but neither exists in all of space nor all of time.

Also as space has at least three dimentions, not only the one the time coordinate has, so you cannot do the trick I did earlier to eliminate space from all the equations describing the universe. I.e. you can formally prove time is just a convenient coordinate, but not do that for (x,y,z) coordinates of space.

You may not be able to do it for all of space, but you may be able to do it just for, say, the x axis. You might think that seems odd and breaks isotropy (rotational symmetry), and I'd agree, but I made a very similar point with respect to spacetime and relativity.

I forgot to mention two other measurable properties of space. It is quite stiff, but a large mass, like the sun, can "bend" it

Like I said earlier, in general relativity it is the spacetime manifold that has the property of being able to curve, and not just exclusively the "space" part. (I think I read somewhere that if you want to imagine spacetime as being embedded in a higher dimensional flat space, then in the worst case you might need up to three external time-like dimensions and around 80 external spatial dimensions.)

and it can support "virtual EM radiation" that can have its longer wavelenghts "shorted out" between two closely separated conducting plates with the unbalance external EM pushing them together with a very tiny but measurable force - I forget the name of it just now. (As long wave lenghts don´t have much energy or make much pressure so to be measurable the plates must be very close together shorting out wave lenghts equal to their separation or longer.)

You wouldn't happen to be referring to the Casimir effect, by any chance? Otherwise I don't recognise what you're trying to describe.

 

[Billy T]

... If you're referring to the so-called "permittivity of space" and "permeability of space", then those are the names of constants in Maxwell's theory of electromagnetism. Despite their names, I don't know why they should be associated with space in particular (as opposed to spacetime), and not just treated as constants in a theory.

well it is more than just the names (and probably why those are the names). The values change when the space is changed - for example vacuum replaced by a block of glass, but when only the time is changed, nothing happens as time does not cause any change - E.g. measure those two now for vacuum (or the block of glass) and a year later and get the same values both times. Again: time has no effects, can not cause anything as it does not really exist.

Yes of course I was referring to the Casimir effect. Thanks for aiding my memory. BTW, it in strange curved electrode geometries can even be repulsive and that I don´t understand. - that may just be by theory, not measured. I had a great long paper on it but lost it in failed hard drive of prior computer.

I sadly note you still have not one property of time to tell me.

How to you distinguish between saying something, that is just a name, like time, which has no effects and no properties and can not be observed, and saying that "that named something" does not exist? To me either implies the other but you said there was a difference. Can you explain what that might be?

For example, it is a fact that no mass equal to that of the sun in the same orbit as Mercury about the sun exists. I know that as it has no effect, can not be observed and has no properties. Or I can make the converse statement to conclude it does not exist from the facts about its lack of properties, effects and observables.

 

[przyk]

well it is more than just the names (and probably why those are the names). The values change when the space is changed - for example vacuum replaced by a block of glass

That's not really the fundamental constants or the properties of "space" changing. Electromagnetism as a fundamental interaction is unchanged in different mediums. What changes is the most convenient way of describing and working with it. The standard convention when dealing with electromagnetism in a medium is to define two new fields: the electric displacement field $$\bar{D}$$, defined in terms of the electric field $$\bar{E}$$ and the local electric dipole moment of the material, and a new "magnetic" field $$\bar{H}$$ defined in terms of the magnetic field $$\bar{B}$$ and the local magnetisation $$\bar{M}$$. In cases where the electric dipole moment and/or magnetisation of a medium are locally proportional to the electric and magnetic fields, you get field equations for $$\bar{D}$$ and $$\bar{H}$$ that resemble Maxwell's equations for $$\bar{E}$$ and $$\bar{B}$$, except with different values of the permittivity and permeability constants. That's where the medium-dependent permittivity and permeability constants come from. They're not the same physical quantities as the vacuum permittivity and permeability constants.

but when only the time is changed, nothing happens as time does not cause any change - E.g. measure those two now for vacuum (or the block of glass) and a year later and get the same values both times. Again: time has no effects, can not cause anything as it does not really exist.

That's not analogous. You're pointing out an example of time translation symmetry in physics. The analogous way to change "space" would be to arrange to have the experiment carried out twice in different places, and just like with time you'd get the same result in both cases because physics is also invariant with respect to spatial translations.

I sadly note you still have not one property of time to tell me.

Locality, topology, and curvature don't count? Granted, we could say these are properties of physics with respect to time rather than time itself, but we could say exactly the same thing about space. My general observation is that wherever you talk about "space" having certain properties, I see no reason you could not have written "spacetime" in its place.

Besides, are the reasons you give for saying space exists your real reasons for believing it does? If you'd lived in the early nineteenth century and knew nothing of general relativity or electromagnetism, would you reach the same conclusion?

How to you distinguish between saying something, that is just a name, like time, which has no effects and no properties and can not be observed, and saying that "something" does not exist? To me either implies the other but you said there was a difference. Can you explain what that might be?

Not really, since "exist" and "property" are rather nebulous words that lack precise definitions (try defining them in a non-circular way without referring to synonyms), and I count on someone reading what I say understanding the point I'm trying to get across despite that. That said, my experience is that the use of the word "exist" in common speech is not reserved just to physical objects that have observable properties. Apart from space and time, possible examples that come to mind are thoughts and human emotions (what observable properties do "love" or "hate" have?) or fields of study (I can't see or interact with the "field of physics" or "politics" or "economics"). Also many quantities in physics, like velocity or momentum or phase, or time and position for that matter, aren't physical objects themselves but exist as properties of physical objects. I don't know about you but I'd find it strange to claim an object exists but its properties don't because they don't have "sub" properties of their own.

I could also address your question by asking you the question I wrote just above: from the perspective of someone with no knowledge of electromagnetism or general relativity, for example because they were born in the early 19th century or earlier, does space exist? Somehow it seems rather odd to me that our ancestors could walk around in space for millions of years and yet we'd need modern physics to establish that it actually exists.

 

[przyk]

Yeah I notice this quite a bit. The debate isn't based on what is said as much on who said it...

On an internet forum like this, where we don't know each other personally, who you are to other posters is what you say.

 

[Farsight]

Because you have not specified 'where' it occurs. The spatial 'where' given is only relative to an 'object' that has moved since the last observation. If you open up the light clock and unfold the light path, it tells you how far the 'object' has moved relative to light speed. The clock is measuring light distance, but labeled as 'time'.

Well said phyti. That's what underlies the invariant spacetime interval. Take two parallel-mirror light clocks, set them running and take one on an out an back trip back, and the light-path lengths in both clocks are the same.

...Also electrons and positron pairs pop up in space (That is 1.022 Mev from nothing but only for the duration that the uncertain principle delta T x delta E permits) unless that happens just at the no escape boundary of a black hole which "swallows" one member of the pair. When that happens the other lives long time adding 0.511 Mev to our non-black hole part of the universe and reduces the mass energy of the black hole correspondingly - an over simplified POV about "evaporation of black holes" that really needs math few can follow to do correctly...

I agree that space exists Billy, but I have to say we have no actual evidence that electron positron pairs pop up in space, and no actual evidence for black hole evaporation. I think it's a non-starter myself because of the infinite time dilation at a black hole event horizon as measured by distant observers. That doesn't mean "time is stopped" down there, but that nothing is moving. It leaves black hole evaporation with something of a problem. Think about it, and IMHO you'll come to see that time travel isn't the only woo peddling by celebrity "physicists".

It seems that through exposure to the popular media of today, even respected scientists sometimes explore the fantasies of science fiction from the perspective of science. Sometimes that is driven by nothing more than money and fame or public exposure and sometimes by a desire to insert at least some measure of science in what, is science fiction, or popular public entertainment.

Fair enough.

Sure there are a few almost fringe prepublication papers, that seem to approach things like antigravity, time travel and perpetual motion, as if they were serious. Even a few published in respected journals. Some may even be deluded into thinking such are serious pursuits, but most are no more than attempts to cater to the Scifi appetites of the lay public.

Fine, only you should leave antigravity out of the list.

Another thing to keep in mind is that there are sometimes differences between honest theoretical explorations of how the theories we currently depend on diverge from the reality we experience, and explorations of their descriptions and predictions of reality.

Agreed.

Sometimes exploring the fantasies that seem to emerge from a theory can tell us as much about how well it describes reality as restricting our explorations to what we can currently see and measure. Time travel is a very good example.

True. My beef is that there are fantasies that can be shown to be just that, but which persist because woo sells. They get in the way of understanding. It's something like what I said to Billy above. Once you understand why time travel is science fiction and get a handle on the "time is motion" thing, you understand gravitational time dilation and why there's an issue for Hawking radiation. Then you become aware that there's no evidence for it, and yet it's bandied about as if it's a fact. You come to realise that there are more fantasies in physics than you thought.

...For the serious part, it's the double standard that gets me...

Well said RC. There's a lot more woo around than the public appreciates. Some of it is absolutely outrageous, and it gets trotted out time and time again. But please don't blame all physicists. Physics is something like a feudal society, where a lot of physicists are serfs.

Guest: do try to join the discussion with sincerity instead of casting snide aspersions that do you no credit.

 

[Farsight]

I don't see your problem here. That is exactly some physicists speculating about time travel from time to time, and I see nothing wrong with it. Criticising the idea of time travel is fine - personally, I don't mind people exploring the idea but I wouldn't bet on it actually going anywhere myself. But I get the impression you'd like to see it practically censored and treated as a taboo subject. That is not a healthy, open minded attitude. Your negative reaction to the whole idea just seems too emotional for my taste.

It isn't emotional, it's rational. Once you understand time you'll come to appreciate that. Try reading Time Explained sometime. Then you come to appreciate just how much nonsense is spouted about time by people who carry influence. Criticising them is taboo and subject to censorship. Try saying Hawking is a quack and here's why and see how far you get.

Huge problems for whom? And what sort of huge problems anyway? It's certainly not a huge problem for any physicist, because we always have detailed mathematical formulations of physics that we understand and can fall back on and test. One physicist might give a mathematical description of a physical system evolving, say in a paper, and loosely refer to time "flowing", but because another physicist reading the paper will have the mathematical description, they will always have the capacity to disagree with the original author's choice of words.

Huge problems for physics. Progress has been poor, funding is getting cut. Look at Fermilab. Look how long the Copenhagen interpretation has held sway, along with "quantum physics surpasseth all human understanding".

I don't know about you, but when I read a paper it is with the aim of understanding the essential content and concepts and concrete results of the paper on my own terms, and not just to memorise the author's catchphrases. I have the same experience with all the physicists I work with: they're all fiercely independent people who like thinking about things in their own way.

Absolutely no problem.

How is that a useful measure of anything? Simply looking at the number of Google hits I get isn't going to tell me who is saying these things, how seriously they mean it, how many of them are actually educated in physics, etc.

I gave you links to show that it isn't just a few physicist enjoying a little speculation from time to time. There's big hitters in the list, peddling nonsense.

More importantly, what about all the physicists and people not talking about the flow of time?

I wish they got more publicity. But often they struggle for publicity because woo gets in the way.

Besides, your assessment simply doesn't square with my own experience, and I am speaking as a physicist who works in a physics research environment in a group that collaborates with other physics research groups around the world. I unavoidably interact with other physicists on a regular basis and I'm simply not seeing this "cult" of belief in time flowing that you seem to think exists. The status of the idea of "time flowing" in physics probably falls in the classic "ask two physicists and you'll get three different answers" bin.

Wake up. Understand time, understand gravity, understand the rest. Like you said on another thread, relativity is something of a meta-theory. Time is the key.

Are you disagreeing with the content of the paper or just the title?

Both. Ellis didn't pay attention a few years back with Magueijo's Varying speed of light theories, he doesn't understand time at all, and he's talking out of his backside about evolving spacetime. Spacetime is a static all-times view.

You make me wish I could actually make you work in a theoretical physics group with international contacts and collaborations for a couple of years.

Feel free.

So time doesn't fundamentally exist like heat doesn't fundamentally exist. I think you'll find that idea breaks down if you take it too seriously. The problem is that the whole idea of motion itself basically presupposes time.

Snap out of that conviction przyk. Be rational. You can see that gap, that space, that distance between your hands, and when you waggle them you can see that motion. Learn to see what's there. You can see space and motion, but you can't see time. Think about wehat a clock really does. All clocks accumulate some kind of regular cyclical motion and show you a cumulative display that you call the time.

While it's true that things like the t coordinate we use in physics and measures of time such as the second are man made conventions, the idea that "change" can occur in the first place is not, and I would argue that is really the essence behind the idea of time. At least the way I see things, you cannot talk about change or motion without implicitly acknowledging and presupposing time.

It's the other way round. Change occurs. Things move. Sh*t happens. It isn't you need time to have motion, it's you need motion to have time. Mull on it.

You also have the problem that time has some basic but important properties associated with it (the sort of thing a mathematician might like to call "topology"): for example, in physics it has special significance when things happen simultaneously (same place and time) or events are "infinitesimally" separated from one another, and you give no explanation of how you recover this.

It doesn't have any properties whatsoever przyk. Simultaneous events can be boiled down to light paths. Infinitesimal separation sounds like clutching at straws.

Special relativity also puts another spanner in the works for you here, since according to relativity there are many different possible measures of time that are all experimentally indistinguishable and equally good as far as physics is concerned. That's a problem because one inertial frame's measure of time is actually a mixture of another frame's space and time measures. So of all the different but equally good sets of x and t coordinates we could use in physics, which x coordinate would represent "real" space and which t coordinate would be entirely this "derived" time of yours?

It doesn't put a spanner in the works at all. I'm the relativity+ guy remember? We define the second and the meter using the motion of light. It all comes down to motion.

I see only two conclusions here: either you have to abandon your idea in light of relativity, or you have to go back to the pre-relativity days of imagining there is some absolute but undetectable state of rest in which the x coordinate would be measuring only space and the t coordinate would be measuring only your "derived" time. General relativity only makes this worse.

No it doesn't. You're clutching at straws trying to cling to a conviction. Look in the mirror and say after me: Some of the things I take for granted have no supporting evidence. I am a rational man, I will examine my assumptions and convictions in order to be a better physicist. By the by, look at A world without time: the forgotten Legacy of Godel and Einstein. I get my relativity straight from the horse's mouth, not from Wheeler, not from Thorne, and not from Ellis.

 

[Guest254]

Guest: do try to join the discussion with sincerity instead of casting snide aspersions that do you no credit.

If you don't want to answer, Farsight, then that's fair enough. Now I recall, you were fairly evasive last time I asked similar questions.

I'd like to make it very clear that I'm not trying to pick on you, or poke fun at you. As I've said before, I think you're a tremendously interesting character.

 

[Farsight]

Stay on topic Guest. Enter into the discussion instead of trying to derail it.

Hence the usefulness of formalising models using mathematics, it isn't open to arm wavey turns of phrase and metaphors. This is another example of why understanding the details of a model is important...

Yes, it's important to understand it. And crucial to that is understanding time. You have to understand what the terms mean, including t. Try to do so, and try to enter into this discussion with sincerity instead of launching into yet another tiresome tirade.

Billy: stick to your guns. I do declare that pryzk is trying a bit of bamboozling here. Watch out for it. Statements like "The standard convention when dealing with electromagnetism in a medium is to define two new fields" are misleading. In Space and Time Minkowski said "Then in the description of the field produced by the electron we see that the separation of the field into electric and magnetic force...". It's one field and two forces resulting in linear and/or rotational motion. It isn't two fields. Minkowski is of course credited with uniting space and time into spacetime. Sadly unlike Einstein he didn't live long enough to understand that space and motion offers a better match to the world we see around us.

 

[Captain Kremmen]

I'd say it's going a bit too far to say "time does not exist". See above where I said time exists like heat exists. Touch a hot stove and you get burnt. That's real enough. So are my grey hairs.

Yes, saying "Time does not exist" was putting it badly.
They are possibly my words, not BillyT's.

What Billy is saying is that is does not exist in and of itself. As a separate entity.
Not that it is meaningless.
Time is a vitally important measurement of the change we experience,
but is not a thing in itself.
His argument that it has no properties, is a good one.
if it has no properties, and cannot be experimented upon, then it cannot be said to exist in itself..
That does not mean it has no meaning, and that units of measurements of time are meaningless.

Your experience of burning yourself on a stove, and growing old would not be changed by this point of view,
but it would make questions about the nature of time meaningless.
You can put the question of "What Is time" in another way, and it is a valid question.
It is this: "Why do things change?"

I think that there is another example of the tendency to confuse units of measurement with real objects, and that is weight.
"What is the nature of weight?" is a similar question, with no answer other than giving its definition in terms of measurement.
We may usefully speak of the weight of something, but that weight is the product of a number of factors,
strength of gravity, mass of the object, direction and speed of movement etc.
So, to hold an apple in your hand and feel its weight, is a real experience,
and when you ask your greengrocer for a pound of them you are talking sense,
but to speak of weight as a separate thing and try to analyse it, is wasted effort.

 

[Motor Daddy]

Yes, saying "Time does not exist" was putting it badly.
They are possibly my words, not BillyT's.

What Billy is saying is that is does not exist in and of itself. As a separate entity.

What that is effectively saying is that if a tree falls in the woods and nobody is there to hear it does it make a noise? Time marches on, whether there is an object in space or not.

You can't say there is no time just because nobody is there to measure it. Time is a duration, which in and of itself needs no physical object to exist. Time needs nothing to exist. All objects in existence measure their motion in time. Objects do not create time. Time is not created, destroyed, reversed, traveled, fast forwarded, re-winded, directional, or otherwise objectified. Time is inevitable, as are distance and volume!

 

[Captain Kremmen]

No, it isn't quite the same as the tree in the wood conundrum.
Without people, things would happen just as they are happening now.

Without people there would not be time, but there would still be change.
Change is the thing that is real, not time.
Time is the way that we measure change, or the lack of change,
by comparing it with something which changes at a set rate,
such as the movement of a pendulum, or turning the hands of a clock,
or the observation of millions of vibrations in a particular crystal.

You can ask the same questions about change as you do about time,
and I think they are valid questions.
Why do things change?
Why does change happen sequentially, bit by bit, and not all at once?

Added later after Farsight's agreement above.
Our experience of sequential change, gives us the impression of time passing.
Like the experience we have of weight, it is immediately useful and a valid way of thinking.

The past and the future exist no more than 4 grams and 6 grams exist
when we weigh something on a scale at 5 grams,
and yet the notion of the greater and the lesser weight must be there
in order for the weight measured to have meaning.
There needs to be the concept of a continuum in order for measurement to have meaning.

And added later still:

I've only thought about it very briefly, just this second actually, but our experience of "hot and "cold" may be further examples.

I thought the same way as Motor Daddy about a day ago,
but this way makes more sense.
If you can't find an answer to a question, maybe the question makes no sense.

One puzzle.
Scientific Philosophers have been dredging over this topic for ages.
The argument that time is not a thing, but a way of measuring does not seem a huge leap.
Why did it take so long?

 

[Aqueous Id]

...The Planck constant defines the kilogram in terms of the second and the meter. By fixing the Planck constant, the definition of the kilogram would depend only on the definitions of the second and the meter...

The Planck constant has units of action. That's kind of sci-fi don't you think? It does magic in this relationship

$$\quad m\lambda \quad =\quad h\sqrt { { \mu }_{ 0 }{ \epsilon }_{ 0 } } $$​

which relates fundamentals of existence on the left with "the fabric of spacetime" on the right. Kinda mind boggling.

I'd say it's going a bit too far to say "time does not exist". See above where I said time exists like heat exists. Touch a hot stove and you get burnt. That's real enough. So are my grey hairs.

Depends on what the meaning of "exist" is. (Kinda like Clinton saying it depends on what the meaning of is is.) In the idea that E is proportional to m, it seems one kind of existence corresponds to another. The c² term has units, but not any that seem to relate to existence. If space exists, and time exists, then velocity would seem to necessarily exist, which seems odd, and then so would its square. But we think of velocity as a character or property of an object of some kind and only in relation to space in its Euclidean sense, which is not one of existence, but of metrics.

On the other hand, the units of c² do magically transform between matter and energy. So it does no disservice to relegating c² (or spacetime itself) to a status of non-existence, since, by all accounts this kind of magic (the transformation, or transmutation) transcends existence.

BTW, what's so unscientific about non-causality and retrocausality? How are things like particle annihilation and creation, or the photon's mere blinking in and out of existence not just as counterintuitive? I like the idea that every "now" is the collision between the forward moving past and the reverse moving future. There's a sci-fi story I'd like to see played out in a true holograph with a live John Williams score.

I don't mind people thinking about science fiction. But I do mind when they present it as science. In my humble opinion really smart people don't peddle time travel. In my humble opinion really smart people understand why it's science fiction.

Some good sci-fi stories are built on the idea of people getting to defy reality once in while. But if we restrict time travel to a more realistic sense it's not too far fetched. For example, to an imaginary observer looking out at the universe from within the first Planck time of the Big Bang, we're all time travelers. Similarly, the Big Bang is receding away from us in time, as is the bottle of men's hair dye you saw at the store, inviting you to restore your youth. Ok so that's being unrealistic. Cheer up. At least you have hair that exists!

 

[Farsight]

Captain Kremmen: I agree with everything you said.

Motor Daddy: sorry, but I'm afraid time doesn't march on. It doesn't march at all. Open up a clock and can you see time marching on? No, all you see is a pendulum swinging, or cogs whirring, or a crystal oscillating. Things "march" in that they change or move, things like pendulums, and cogs, and all those clocks which clock up some regular cyclic motion and show you how much of it has occurred. Then you can look at distance and gauge the rate of motion of other things. There is no mystery, there is no time travel, there is no motion in time. There's motion, in space, and that's it. Once you see it you'll say aaaahhhh!

 

[Motor Daddy]

No, it isn't quite the same as the tree in the wood conundrum.
Without people, things would happen just as they are happening now.

Without people there would not be time, but there would still be change.
Change is the thing that is real, not time.
Time is the way that we measure change, or the lack of change,
by comparing it with something which changes at a set rate,
such as the movement of a pendulum turning the hands of a clock,
or millions of vibrations in a crystal.

You can ask the same questions about change as you do about time,
and I think they are valid questions.
Why do things change?
Why does change happen sequentially, and not all at once?

You're wrong. Time has always existed, and time will always exist. Time is inevitable, and is independent of mass and distance. Time is the concept of duration. Since there is duration we can use it to complete the measure of motion (change of coordinates of objects over a duration of time).

 

[Motor Daddy]

Captain Kremmen: I agree with everything you said.

Motor Daddy: sorry, but I'm afraid time doesn't march on. It doesn't march at all. Open up a clock and can you see time marching on? No, all you see is a pendulum swinging, or cogs whirring, or a crystal oscillating. Things "march" in that they change or move, things like pendulums, and cogs, and all those clocks which clock up some regular cyclic motion and show you how much of it has occurred. Then you can look at distance and gauge the rate of motion of other things. There is no mystery, there is no time travel, there is no motion in time. There's motion, in space, and that's it. Once you see it you'll say aaaahhhh!

I love ya, buddy, but I have to call BS when I see it, and it is BS to say that time is somehow dependent on mass and distance.

There is mass, the concept of matter which has physical properties.
There is distance, the concept of 1 of the 3 dimensions of volume, which is 3 dimensional space.
There is time, the concept of duration.

 

[Farsight]

I love you too MotorDaddy, but open up that clock and you don't see time marching on. You just see things moving. That ain't BS. A clock really does "clock up" some kind of motion. It doesn't actually "measure the flow of time".

The Planck constant has units of action. That's kind of sci-fi don't you think?

No, I think it's telling you something really fundamental and thrilling. You know about pair production, where we can create an electron (and a positron) out of an electromagnetic wave aka a photon. Now look at Compton scattering. The electron acquires kinetic energy, and the photon is diminished. Now do another Compton scatter on it, and another and another, and keep going until it isn't discernible any more. It's been converted into electron motion. And get this, we could have made an electron (and a positron) out of it. So what's an electron made out of? Action! Or motion if you prefer. This is why motion is so crucially important in physics.

Depends on what the meaning of "exist" is. (Kinda like Clinton saying it depends on what the meaning of is is.) In the idea that E is proportional to m, it seems one kind of existence corresponds to another.

Sounds good to me.

The c² term has units, but not any that seem to relate to existence.

It does, but people don't learn about the relationship between energy/momentum and inertia because there's so much woo being peddled these days. See Einstein's E=mc² paper. "The mass of a body is a measure of its energy-content". It isn't a measure of the resistance offered by cosmic treacle.

If space exists, and time exists, then velocity would seem to necessarily exist, which seems odd, and then so would its square. But we think of velocity as a character or property of an object of some kind and only in relation to space in its Euclidean sense, which is not one of existence, but of metrics.

Space certainly exists, light certainly exists, action or motion certainly exists, and things made of it certainly exist. And they move. But we just can't say the same about time.

On the other hand, the units of c² do magically transform between matter and energy. So it does no disservice to relegating c² (or spacetime itself) to a status of non-existence, since, by all accounts this kind of magic (the transformation, or transmutation) transcends existence.

It isn't magical, and it's not something I'd like to relegate to the status of non-existence. What I want is motion given some priority over time.

BTW, what's so unscientific about non-causality and retrocausality?

They're like unicorns. They're based on total misunderstanding and there's no supporting evidence.

How are things like particle annihilation and creation, or the photon's mere blinking in and out of existence not just as counterintuitive?

They aren't. See the wiki Atomic Orbital article? See the bit that says The electrons do not orbit the nucleus in the sense of a planet orbiting the sun, but instead exist as standing waves. For pair production, think in terms of a electromagnetic wave going along at c getting chopped in half and each half curling up into a wave going round and round at c. The passing electromagnetic field variation is now a standing field. We can diffract an electron. Not because of magic, but because of the wave nature of matter.

I like the idea that every "now" is the collision between the forward moving past and the reverse moving future.

We'll have to agree to differ on that.

There's a sci-fi story I'd like to see played out in a true holograph with a live John Williams score. Some good sci-fi stories are built on the idea of people getting to defy reality once in while.

I like science fiction stories. I used to write them you know. But nowadays I find that for some reason I don't like them if they're too fantastic. Something to do with suspension of disbelief maybe.

But if we restrict time travel to a more realistic sense it's not too far fetched. For example, to an imaginary observer looking out at the universe from within the first Planck time of the Big Bang, we're all time travelers. Similarly, the Big Bang is receding away from us in time,

Sorry aqueous, there's just more and more motion that's occured since the big bang. (Huh, I nearly said as time goes on along with it's been a long long time). We aren't really time travellers at all.

...as is the bottle of men's hair dye you saw at the store, inviting you to restore your youth. Ok so that's being unrealistic. Cheer up. At least you have hair that exists!

LOL, but not as much as I'd like! But hey, I'm fit and well and have all my teeth, and a four year-old etc etc. I'm happy in my skin.

Sheesh, look at the time. Gotta go.