Philosophy Discussion Forums

Atreyu:

No. What I meant by "fundamental property" is something like the idea of "force". The four known forces are "fundamental properties" of the Universe.

I disagree on this point. They're just our current models. Always subject to update. In fact, they already have been updated. The electromagnetic and weak nuclear forces are already unified into the "electroweak" force in the Standard Model of Particle Physics. And it's perfectly possible that it could be deemed more useful, at some point in the future, to replace them. The concept of "force" in the Newtonian sense is already regarded as outdated.

What I mean is that if the Universe can be regarded as having the fundamental property of expansion/growth, i.e. if we can regard this expansion/growth as something like one of the four known forces of the Universe, then we can dispense with needing to make current particle theory conform to what we see happening. We no longer need to assume that some particle is involved in the accelerating expansion. We can just say that this fundamental property overrides, or takes precedence, over the force of gravity (another fundamental property) at the most macro-level of the Universe. Much like gravity takes precedence over electromagnetism when we are explaining the behavior of large cosmic bodies. We don't need to make electromagnetism fit in with the behavior we see in large cosmic bodies. We merely say that the force of gravity is more applicable here, that it applies to large bodies, while electromagnetism, another fundamental property, only applies at the atomic level. The force of gravity overcomes any concerns we might have concerning the charges of electrons and protons, because on that scale (large cosmic bodies) the force of gravity plays a much bigger role than the force of electromagnetism does.

Yes, it's true that we do that. We do regard there as being a "realm" in which General Relativity dominates and "realm" in which Quantum Mechanics (The Standard Model) dominates. But that kind of thing is always regarded as a stop-gap; a staging post on the way to a more unified theory. I think one problem with this idea of completely different models applying at different scales is that there is then an arbitrarily decided junction point where you switch models. It seems too artificial. That's why, for example, classical Newtonian mechanics is not regarded as being a different realm from Quantum Mechanics, but rather it is a statistical approximation to QM at large scales. QM contains classical mechanics as a simplified special case.

We do have force and bosons are identified with forces bosonic forces ex exchange of mesons between proton neutrons or any two hadrons. These are the facts, for those care about facts.

Some here at philo forums attempt to ignore, skew and mislead truth. Yet the truth still exists irrespective of their efforts.

Some here believe shape of occupied space is irrelevant, and they obviousl disregard truth of areodynamics.

The list goes on of various truths some attempt put out of sight and out mind. Yet truth still exists.

We know, or believe there exist a pushing-OUTward and away phenomena, identified as dark energy, that, Ive repeated, over last year now, I believe is a 2nd property of space-time. We do not get any more fundamental than space-time properties. imho

I believe pushing-OUTward expansive, dark energy, is also a resultant of pulling-INward contractive gravity. Stars are believed to be resultants of gravity and some stars push-OUTward photons of radiation.

Some stars expand as larger red stars ex Sol is believed to become a red giant.

Some stars go nova on us. Some go super-nova on us an some go hyper-nova on us, and all of those expansive, pushing-OUTward phenomena are believed to be resultant of pulling-INward contractions of gravity.

The brain sends only one signal to muscles and that signal is to contract INward. The womb contracts and fetus/baby is expelled etc....

OUTward expanding, finite occupied space Universe, leads to alledged heat death of occupied space Universe. The Universe is believe to become one/single very large, lowest frequency ( longest wave ) photon.

This phase of Universe is the weakest state/phase, and gravity now takes over. Gravity is the ultimate determiner of the fate of Universe, not dark energy and not inflation. Gravity is like the tortise that is eternally trudging INward, even as the rabbit of dark energy and or inflation speed-off and OUTward only to eventually burn out and the gravity tortise pulls-these weaken ones back INward.

Rr6 wrote:.
and the gravity tortise pulls-these weaken ones back .

As you must already know, the gravity tortise is an endangered species. What will happen to the universe if it becomes extinct?

Steve3007 wrote:

Do you regard an open declaration of lack of knowledge on a subject as a failing?

Not at all. But it does give a carte blanche to every crackpot and knucklehead who want to express an opinion on the matter; and lots of them do!

Steve3007 wrote:Atreyu:

No. What I meant by "fundamental property" is something like the idea of "force". The four known forces are "fundamental properties" of the Universe.

I disagree on this point. They're just our current models. Always subject to update. In fact, they already have been updated. The electromagnetic and weak nuclear forces are already unified into the "electroweak" force in the Standard Model of Particle Physics. And it's perfectly possible that it could be deemed more useful, at some point in the future, to replace them. The concept of "force" in the Newtonian sense is already regarded as outdated.

What I mean is that if the Universe can be regarded as having the fundamental property of expansion/growth, i.e. if we can regard this expansion/growth as something like one of the four known forces of the Universe, then we can dispense with needing to make current particle theory conform to what we see happening. We no longer need to assume that some particle is involved in the accelerating expansion. We can just say that this fundamental property overrides, or takes precedence, over the force of gravity (another fundamental property) at the most macro-level of the Universe. Much like gravity takes precedence over electromagnetism when we are explaining the behavior of large cosmic bodies. We don't need to make electromagnetism fit in with the behavior we see in large cosmic bodies. We merely say that the force of gravity is more applicable here, that it applies to large bodies, while electromagnetism, another fundamental property, only applies at the atomic level. The force of gravity overcomes any concerns we might have concerning the charges of electrons and protons, because on that scale (large cosmic bodies) the force of gravity plays a much bigger role than the force of electromagnetism does.

Yes, it's true that we do that. We do regard there as being a "realm" in which General Relativity dominates and "realm" in which Quantum Mechanics (The Standard Model) dominates. But that kind of thing is always regarded as a stop-gap; a staging post on the way to a more unified theory. I think one problem with this idea of completely different models applying at different scales is that there is then an arbitrarily decided junction point where you switch models. It seems too artificial. That's why, for example, classical Newtonian mechanics is not regarded as being a different realm from Quantum Mechanics, but rather it is a statistical approximation to QM at large scales. QM contains classical mechanics as a simplified special case.

My point, Steve, was merely that if we regarded the apparent accelerating expansion of the Universe as being the result of some inexplicable force, much like we do with gravity, then the problem could be solved much differently. Note that no one knows what a force is, nobody knows if there are gravitrons or not. A force, like gravity, was merely invented to explain what we observe. We saw large bodies being attracted to each and so we explained it by asserting that there is exists this mysterious force we will label "gravity", and then by calculating and measuring things we deduced the laws and rules applicable to this supposedly existing "force". The idea of force is merely an idea, an explanation, a description. So why can we not use this same concept in explaining the accelerating expansion of the Universe? Why cannot we assert that there is this force, which we will call "Expansion", which overrides the counter-force of gravity? Like Newton did when the apple came down and hit him on the head? Why limit ourselves to our current model of 3 fundamental forces (principles)?

Instead, there is an implicit assumption that only 3 forces can be used in our explanation, which leads to the necessity of the Higgs-boson. As if we can't make up the existence of another force to go along with the first three that we already have made up in order to explain things....

Atreyu wrote:Instead, there is an implicit assumption that only 3 forces can be used in our explanation, which leads to the necessity of the Higgs-boson. As if we can't make up the existence of another force to go along with the first three that we already have made up in order to explain things....

Gravity is not a made up force. Indirect evidence has been shown twice now;

1) once in 70's via two binary stars loss of energy,

2) recent LIGO experiements clock-a-fying rather than a quantizing or quantification of gravity by retarding the laser light arrival back at its source.

The truth is out there for those who seek it, those who don't and those who scoff at it. imho

r6

Rr6 wrote:Gravity is not a made up force. Indirect evidence has been shown twice now;

1) once in 70's via two binary stars loss of energy,

2) recent LIGO experiements clock-a-fying rather than a quantizing or quantification of gravity by retarding the laser light arrival back at its source.

The truth is out there for those who seek it, those who don't and those who scoff at it. imho

r6

Gravity, along with electro-magnetism and nuclear forces, are "made up" in the sense that they are just explanations for observable phenomena. The evidence for gravity is obvious --- large cosmic bodies attract each other. The evidence for electro-magnetism and nuclear force is obvious too ---> things are the way they are at the atomic scale. But this does not change the fact that the forces themselves are merely descriptions/ideas/explanations for why things are the way they are. Nobody imagines forces existing as things or objects. They are general properties of the Universe, deduced from the evidence.

Now, why not admit that apparently we have discovered a previously unknown force, which permeates it and affects it everywhere (as the other forces do), namely, the force that is apparently causing the Universe to expand at an accelerating rate? Why is this forbidden? Why do we have to try and reconcile this observation within the context of only the three already postulated forces? Especially when doing so gives us a simpler and more coherent view of the Universe, without needing a specific array of subatomic particles in order to explain it?

Atreyu:

My point, Steve, was merely that if we regarded the apparent accelerating expansion of the Universe as being the result of some inexplicable force, much like we do with gravity, then the problem could be solved much differently. Note that no one knows what a force is, nobody knows if there are gravitrons or not. A force, like gravity, was merely invented to explain what we observe. We saw large bodies being attracted to each and so we explained it by asserting that there is exists this mysterious force we will label "gravity", and then by calculating and measuring things we deduced the laws and rules applicable to this supposedly existing "force". The idea of force is merely an idea, an explanation, a description. So why can we not use this same concept in explaining the accelerating expansion of the Universe? Why cannot we assert that there is this force, which we will call "Expansion", which overrides the counter-force of gravity? Like Newton did when the apple came down and hit him on the head? Why limit ourselves to our current model of 3 fundamental forces (principles)?

I think your assessment of what a force is is absolutely right. It is a model in our minds; something that we infer in order to explain various patterns in our observations. And yes, we could do this with other things. The thing that I note is that we don't seem to want to, and that's interesting.

The thing is, it's all a model in our minds to help us to describe and predict our observations. Not just forces. So the question, I think, is where, if ever, do we stop looking for deeper and deeper, more and more generally applicable, models. And I think the answer to that question is somewhat arbitrary. Whenever we feel like it.

It's clear that "the physics community" is not satisfied with the force concept, in the "action at a distance" sense that was suggested by Newton. That's why gravity, electromagnetism, the weak force (electroweak force) and the strong force often tend to be referred to as "interactions" rather than forces.

Steve3007 wrote:I think your assessment of what a force is is absolutely right. It is a model in our minds; something that we infer in order to explain various patterns in our observations. And yes, we could do this with other things. The thing that I note is that we don't seem to want to, and that's interesting.

The thing is, it's all a model in our minds to help us to describe and predict our observations. Not just forces. So the question, I think, is where, if ever, do we stop looking for deeper and deeper, more and more generally applicable, models. And I think the answer to that question is somewhat arbitrary. Whenever we feel like it.

It's clear that "the physics community" is not satisfied with the force concept, in the "action at a distance" sense that was suggested by Newton. That's why gravity, electromagnetism, the weak force (electroweak force) and the strong force often tend to be referred to as "interactions" rather than forces.

Indeed, it is interesting that science does not view expansion as a sort of universal force. Because the accelerating expansion reveals something very fundamental about the Universe which obviously is still unknown. Science thinks that what it reveals is that a subatomic particle must be missing in our particle theory model. But what it really reveals is that the Universe has a fundamental property which science hitherto had not imagined or conceived....

Arguably it amounts to pretty much the same thing.

The whole concept of particles and the idea that these "interactions" (formerly known as forces) are mediated by those particles is just a model designed to describe and predict various observations. Do electrons, photons or muons "really exist"? Well, as concepts they've been fairly useful. Various observations, such as flashes of light on the screens of cathode ray tubes, are successfully described and predicted by invoking the concept of a little particle called an electron with various properties. So, in that sense, they exist.

If invoking the concept of another particle in the family of particles helps to describe this relatively new observation (the apparent accelerating expansion of the universe) then I guess there's at least some case for invoking it.

Steve3007 wrote:Arguably it amounts to pretty much the same thing.

The whole concept of particles and the idea that these "interactions" (formerly known as forces) are mediated by those particles is just a model designed to describe and predict various observations. Do electrons, photons or muons "really exist"? Well, as concepts they've been fairly useful. Various observations, such as flashes of light on the screens of cathode ray tubes, are successfully described and predicted by invoking the concept of a little particle called an electron with various properties. So, in that sense, they exist.

If invoking the concept of another particle in the family of particles helps to describe this relatively new observation (the apparent accelerating expansion of the universe) then I guess there's at least some case for invoking it.

Oh, of course there is a "case" for invoking it. Keeping particle theory intact.

My point is that viewing it in terms of nano-particles detracts attention from what the accelerating expansion suggests, which is fairly obvious once one looks at the Universe from a macro point of view and without regard to what particles it may or may not be composed of, and that is, that there is apparently another reason/explanation for the expansion of the Universe, in addition to some primordial 'big bang'.

Add growing matter/mass and you have the Inflation model.

The accelerating expansion is evidence in favor of the Inflation model over the Big Bang model, and the only reason this is not obvious is because fixed matter/mass is so rigidly assumed to be an absolute law....

-- Updated June 8th, 2016, 10:35 pm to add the following --

I'd like to add that the accelerating expansion is also evidence of the Inflation model, because if the Universe can be thought to be sort of "inflating" itself, then we would be expect the force behind the inflation to become stronger as the Universe became larger. The Universe began as something very small, then it began inflating, and inflating in terms of matter, mass, energy, space, and volume, and the larger it gets the faster the rate of inflation. No big bang needed....

'Dark energy' and 'dark matter' were invented by scientists to keep the big bang model, along with conservation of energy/mass as a universal property, intact. The only way the big bang could be true, and for the Universe to have a fixed amount of total energy/mass/matter, is for there to be some 'dark matter' and 'dark energy' we don't know about, causing this accelerating expansion.

Actually, all that we don't know about is that total matter/mass/energy is increasing over time as the Universe expands, i.e. the Universe is inflating, and there never was, nor could have been, any 'big bang'....

'Dark energy' and 'dark matter' were invented by scientists to keep the big bang model, along with conservation of energy/mass as a universal property, intact.

I disagree. Dark energy is the label to identify an observed cosmological phenomena. Dark energy is very similar too, or exactly the same as Einsteins cosmological constant.

Very little is known regarding the accelearting expansion of Universe or as space-time aspect of Universe.

I believe dark energy is 2nd property of space-time ergo Space -Time - Space

Uni-Verse = Universe = God = Cosmos etc......

Our labels identify specific,
1} occupied space phenomena, or direct relationships those phenomena,

2} metaphysical-2, macro-infinite non-occupied space,

3} metaphysical-1, mind/intellect/concepts and as a resultant of #1 above , occupied space aggregations as a human.

r6

Philosophy Explorer wrote:It would seem that dark energy is the opposite of gravity where gravity pulls and dark energy pushes. Yet gravity is described as a force while dark energy is described as...well, energy.

Also with dark energy, within our solar system, it doesn't seem to operate while gravity does and gravity helps to keep our planets in orbit about our Sun.

Can anybody add to this?

PhilX

It's an excellent question and pretty hard to understand. Basically, the modern idea of a "force" is that particles emit (throw) "gauge bosons" (particles - photons are an example) at each other. Actually, they usually emit virtual gauge bosons at each other. Virtual particles are ones you never detect, but seem to exist all the same. So with electrically charged particles, they throw (virtual) photons at each other. Depending on the overall system and what charge they have, this will cause charges to be repelled or attracted to each other. A proton throws a photon at an electron, and the electron is attracted to the proton (due to the Heisenberg uncertainty principle and their overall energy, which is affected by charge). Electrons throw a photon at each other, and they electrons repel.

This is what three of the four fundamental forces do (electromagnatism, and the strong and weak nuclear forces). They throw (mostly virtual) particles at each other. This results in moving away or towards, and we call it a force. the gauge bosons are the force mediators.

Gravity, however, is different (and arguably not really a force) because objects move towards each other because they each warp space time, so bodies sort of "fall" towards each other. It's analogous to how two cannonballs on a trampoline would roll towards each other. There is no particle exchange here (probably, but gravitons might exist), so if gravity is properly called a force, it's probably different than the other three.

So, what about dark energy? The idea with this is there is some "substance" throughout the universe that does not interact with matter in any way except gravity. Electromagnetism and the nuclear forces don't interact with it. The reason we feel and can touch something is because electron clouds on our hands (or other parts of our bodies) repel the electron cloud in another substance, like a rock (through photon exchange). But this hypothesized "substance" doesn't interact with photons (virtual or real), they go right through, so we can't touch it or feel it. We can't see it either, because photons go right through (hence the name "dark" energy).

The overall effect of this substance is that it permeates the universe, as the universe gets bigger, more and more of it fills up the universe. Sean Carrol describes it as a feature of space itself. AS space gets bigger, you get more of this energy (a weird "substance" if you can call it that). Why, because it's a part of space, sorta. It's like your balloon expands and keeps filling up with air. The effect of this is to keep the curvature of space constant. If the curvature of space is constant, then the universe expands at a constant rate. However, in GR cosmological parlance, this means that the doubling time (or tripling time, or whatever) for the universe stays constant. SO to get twice as big, we need say, 10 billion years. To get four times as big, we need, 20 billion years. TO get 8 times bigger, we need 30 billion. That's what constant rate means to universe expansion.

Since this "substance" has energy, and E=mc^2, you might expect that it contributes gravity to the universe, and that would cause more attraction and the expansion of the universe to slow down. The energy does do this, but the other effect overwhelmes this effect.

The other thing to note is that masses still attract each other through gravity, and even though there is lots of dark energy between them. If dark energy were a sort of opposite gravitational force, dark energy would inhibit the gravitational force, making the attraction between objects less, but it doesn't, another reason "dark energy" is not a force.

Mgrinder:

This is what three of the four fundamental forces do (electromagnatism, and the strong and weak nuclear forces). They throw (mostly virtual) particles at each other. This results in moving away or towards, and we call it a force. the gauge bosons are the force mediators.

A side point: These analogies can sometimes get amusingly strained. I remember when first learning about the particle exchange model for these three interactions, the image used was of two people throwing a ball backwards and forwards to each other such that the ball exchanges momentum between them. But that analogy only works for repulsive forces. So for attractive forces the analogy used was of a boomerang that goes around the back and hits each thrower from behind. I'm not sure if the use of that analogy was wise. A bit contrived.

Steve3007 wrote:Mgrinder:

This is what three of the four fundamental forces do (electromagnatism, and the strong and weak nuclear forces). They throw (mostly virtual) particles at each other. This results in moving away or towards, and we call it a force. the gauge bosons are the force mediators.

A side point: These analogies can sometimes get amusingly strained. I remember when first learning about the particle exchange model for these three interactions, the image used was of two people throwing a ball backwards and forwards to each other such that the ball exchanges momentum between them. But that analogy only works for repulsive forces. So for attractive forces the analogy used was of a boomerang that goes around the back and hits each thrower from behind. I'm not sure if the use of that analogy was wise. A bit contrived.

Which is why Feynman made the point that you can't really understand this stuff without the math. Words and language just plain fail at many key concepts. However, you can get these concepts across with the math, but you can't express with words.

The reason for attraction is still due to their charges. A proton and electron are near each other, say in a hydrogen atom. Because of the charges, the total energy is negative. The proton or electron emits a virtual photon, but energy is not conserved with this, which is allowed for short time intervals by the Heisenberg uncertainty principle. The effect of this is to make the total energy more negative (i.e. if it was -100 eV, now it is -110 eV). If you now calculate the new position with this new total energy, the new position is closer to the proton. Therefore, an attractive force. Why? because of the total energy dictated by charges.

It's better put by the math in the link, which makes my above point.