Talk:Matter/Archive 2

Archive 1

Archive 2

objects are made from molecules

The following statement:

“Over time an increasingly fine structure for matter was discovered: objects are made from molecules, molecules consist of atoms, which in turn consist of interacting subatomic particles like protons and electrons.”

appears to me to suggest that the view of matter as “made from molecules, molecules consist of atoms, which in turn consist of interacting subatomic particles like protons and electrons” is somehow the accepted formulation of this subject. Clearly, that is far from so. It is more like the early 20th century view. A simple example of a contrary view is "dark matter", which has no relation to this formulation. If we restrict ourselves to ordinary matter, then the "quark - lepton" definition allows for the "quark-gluon" plasma, also not compatible with the above statement.

For these reasons, a better statement would be:

“Over time an increasingly fine structure for matter was discovered: for example, in one definition of matter, objects are made from molecules, molecules consist of atoms, which in turn consist of interacting subatomic particles like protons and electrons.”

This statement does not conflict with any statements made later in the article. Brews ohare (talk) 17:35, 18 August 2010 (UTC)

Or maybe: “Over time, increasingly detailed models of matter have been discovered. For example, matter is known to be made up of atoms, which in turn consist of protons, electrons, and neutrons. These particles can be broken down further into smaller parts still— leptons, gluons, etc. Quantum theory implies that the granularity be necessarily limited to some finite size, however, and relativistic effects must be taken into account as well.”, or some such.

Sebastian Garth (talk) 19:28, 18 August 2010 (UTC)

Brews such a statement does not make any sense. In all definitions of matter objects are made from molecules. It is just that in some definitions of matter there are forms of matter that do not form objects. (Dark matter may or may not form objects, if objects can be formed from dark matter there is likely to be such a thing as a dark molecule.TimothyRias (talk) 22:57, 18 August 2010 (UTC)

A bit of a quibble. I guess. You might read the "peeling of the onion" viewpoint. On that basis each layer is a "new" theory of matter that includes its predecessors, but goes beyond them to include new forms. Thus, quark-gluon plasma is not made up of molecules. Consequently, matter in the quark-lepton building block model includes items that are not matter in the atoms and molecules building block definition. Another example is neutron degenerate matter, composed purely out of neutrons (not molecules or atoms). Don't you agree? Brews ohare (talk) 13:26, 19 August 2010 (UTC)

Is this a quibble over what an "object" is: for example, is a neutron star or a quark-gluon plasma an "object"; or is it about whether all "matter" is made up of molecules (that depends on the building block model adopted: yes, for the atoms & molecules blocks, no, for the quark-lepton blocks). Brews ohare (talk) 15:10, 19 August 2010 (UTC)

Matter therefore is anything that contributes to the energy–momentum of a system, that is, anything that is not pure gravity

The header is a statement that appears here. As a non-expert, I find this statement, and indeed this section to be obscure. For example, doesn't relativity say inertial mass = gravitational mass and therefore is part of the geometry of space-time? So what is this "matter" that is unrelated to "pure" gravity? It seems that it is something with another form of mass, different from inertial or gravitational mass? The cited source is not available on-line to elucidate the argument, and this section doesn't seem to be self-explanatory.

More should be said, as this appears to be a very pertinent subject, and more sources provided. Brews ohare (talk) 14:08, 19 August 2010 (UTC)

Maybe this source would be helpful? Brews ohare (talk) 14:15, 19 August 2010 (UTC)

Headbomb has suggested that this section is “not confusing, this is a very concise and structured section”. That is an assertion, of course, not an explanation of the above questions about this section, which may be clear to some, but will not be clear to many others. Brews ohare (talk) 11:38, 20 August 2010 (UTC)

In particular, the term pure gravity is a technical term referring to gravity uncoupled to matter, a concept that is pretty hard to grasp for the non-expert (who probably has Newton's theory of gravitation between masses in mind) and completely unexplained here. The connection between the stress-energy-momentum tensor and pure gravity also is left dangling. Although a detailed explanation of such matters is beyond this article, at a minimum some clear English statements should be made, sources provided, and links to other WP articles where an interested reader can learn what is going on here. In addition, a connection should be made to the other definitions of matter: for example, does this relativistic version of matter complement or contradict these definitions? Is a stress-energy-momentum tensor a ‘physical object’ in the sense of the lead sentence of this article? For example, does this definition include dark matter and dark energy? Does it include but transcend the particulate theory? And so forth. Brews ohare (talk) 15:12, 20 August 2010 (UTC)

I added a source for a discussion of the term "pure gravity", but IMO this section still needs more work, as outlined above. Brews ohare (talk) 19:04, 20 August 2010 (UTC)

The substance of which all physical objects are made

Does the phrase “Matter is a general term for the substance of which all physical objects are made” contain more than the phrase “Matter is a general term for what makes up all physical objects”? Headbomb says “substance is an important word and concept”. I'd agree that "substance" has a lot of baggage associated with it, for example, see this WP article. In my opinion, in this introductory sentence, substance is only a place holder without content, and the baggage associated with this word gives you a false sense of security that you actually said something. In fact, however, what you have done is to introduce a plethora of unintended consequences. From the old viewpoint of operational definitions the word substance is metaphysical gobbledygook, despite its use by the BIPM. If there is something of Substance theory that is intended here, it should be pointed out. Brews ohare (talk) 12:27, 20 August 2010 (UTC)

The on-line dictionary defines substance as: “ That which has mass and occupies space; matter.” indicating what we have here is, at best, circular. Brews ohare (talk) 14:12, 20 August 2010 (UTC)

Reversion by Headbomb

Headbomb: This reversion of yours with the comment “this is not an example, and "had been" is not the correct tense, please stop twiddling with these near-trivial rephrasing of everything” is annoying. This reverted edit contains a link for your convenience to a Talk page discussion that you show no indication of being familiar with. I suggest you read it, and comment upon why it is not applicable.

Also, the edited sentence most certainly presents only an example, and not a universal statement. For instance, it would be completely incorrect to say “neutron stars are made from molecules, molecules consist of atoms, which in turn consist of interacting subatomic particles like protons and electrons.” Yet, neutron stars are most certainly objects. Consequently, the statement you prefer: “objects are made from molecules, molecules consist of atoms, which in turn consist of interacting subatomic particles like protons and electrons” is most obviously stating an incorrect generality.

I suggest that you fix the sentence “Over time an increasingly fine structure for matter was discovered: objects are made from molecules, molecules consist of atoms, which in turn consist of interacting subatomic particles like protons and electrons” so that it suits you, but actually is accurate. Brews ohare (talk) 17:58, 20 August 2010 (UTC)

Since I would like this page to not have 20 archives of debates on semantics, I'll simply decline to comment. You're about to be topic banned from physics for a year, so commenting would be a waste of time in all possible scenarios anyway. Headbomb {talk / contribs / physics / books} 18:15, 20 August 2010 (UTC)

Fixing a fallacious statement is not a matter for debate, and is independent of my fate. Brews ohare (talk) 18:17, 20 August 2010 (UTC)

It appears as though you haven't even bothered to read what has been said, unfortunately. Brews ohare (talk) 18:19, 20 August 2010 (UTC)

Amount of substance

This revert removed this long-standing subsection previously included under "Definitions":

Amount of substance

The international standards organization Bureau International des Poids et Mesures (BIPM) uses the terminology "amount of substance", rather than "matter". To quote the SI brochure:

"Amount of substance is defined to be proportional to the number of specified elementary entities in a sample, the proportionality constant being a universal constant which is the same for all samples. The unit of amount of substance is called the mole, symbol mol, and the mole is defined by specifying the mass of carbon 12 that constitutes one mole of carbon 12 atoms. By international agreement this was fixed at 0.012 kg, i.e. 12 g.

• 1. The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12; its symbol is "mol".
• 2. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles."

The reason provided for this deletion was the edit summary “I don't see how this section in anyway describes a definition of matter”.

IMO this subsection is very clearly related to the subsequent "atoms and molecules" definition, and is in fact a generalization of that definition in that it allows for "elementary entities" of matter of a more general nature. Inasmuch as this formulation comes from the international standards organizations, it seems to me important that it be included in this article, as it was previously, and this reversion should be overridden. Brews ohare (talk) 18:54, 20 August 2010 (UTC)

Well, I disagree. The SI quantity for a number of particles has nothing to do with a definition of matter. At best the "amount of substance" is a candidate as a quantity that quantifies matter (like mass or energy), but if that is the reason to mention it then that should be made clear.TimothyRias (talk) 23:27, 20 August 2010 (UTC)

OK Timothy: We can agree to differ on this, but that seems to suggest some clarification of substance should be made. The lead sentence says:

Matter is a general term for the substance of which all physical objects are made.

The BIPM says:

Amount of substance is defined to be proportional to the number of specified elementary entities in a sample.

These statements might lead to:

Amount of matter is related to the number of specified elementary entities in a sample.

This sounds like a version of the particulate theory of matter to me. The rest of the BIPM statement spells out what the "official" building blocks may be, an approach that appears to be early 20'th century. If the lead sentence doesn't mean substance in the BIPM sense, what does it mean? Brews ohare (talk) 14:12, 21 August 2010 (UTC)

BTW, the present linking of "substance" in the first line to the article on "Physical property, a measurable property the value of which determines a physical system's state" is not a clarification of substance, but a red herring. Brews ohare (talk) 14:24, 21 August 2010 (UTC)

A link instead to Substance theory would actually be pretty good (a change of heart on my part) because it introduces this topic with the very pertinent observation that substance theory is the posit “that a substance is distinct from its properties”, which is exactly what is wanted here. Brews ohare (talk) 15:01, 21 August 2010 (UTC)

I'd add that this subsection provides about the best support available for the use of the term "substance" in the introduction, so it is surprising that the "substance" supporters also want to eliminate this definition of their terminology. Brews ohare (talk) 19:10, 20 August 2010 (UTC)

Disruption?

As usual, when Brews ohare brings his attention to an article, the vast majority of all article edits and talk page edits are his, even as various other editors try to moderate what he's doing. This kind of pushy editing is disruptive, but he continues to deny that that's what it is. For the record, he has about two-third of the 36 or so talk page edits and 60% of the 50+ article edits on this article since he showed up on Aug. 6, and the rest are mostly other editors trying to moderate his influence. There were no talk comments in July, which is closer to a typical steady state when normal editors aren't bringing their full-time focus to an article to remake it in their image. Dicklyon (talk) 22:59, 20 August 2010 (UTC)

Well, Dick, how about actually itemizing specific actions that you think are beyond the pall, with clear descriptions of how they are outside normal activity, and that obviously violate some or other guidelines, eh? Vague accusations followed by a question mark? When you are not even a party to the discussion? Come on, Dick? Brews ohare (talk) 00:36, 21 August 2010 (UTC)

My point is about the disruptive pattern, not the specific edits. As I've pointed out many times, by dominating the discussion you make it hard for others to collaborate. I'm asking if others see it the same way, since I think you might start to hear it if more would discuss it at that level. Dicklyon (talk) 16:11, 21 August 2010 (UTC)

A delicate distinction, perhaps: a disruptive pattern of behavior consisting of perfectly normal edits, but so numerous as to interrupt participation by others. Is that the idea, Dick? I see no impediment to TimothyRias and Headbomb simply bulldozing their views on the Talk page and pretty much ignoring my remarks. On the article page, no edits are possible for me (except for adding a reference or two) as they revert them immediately. Doesn't appear my "pattern of disruption" is any more disruptive than any individual one of my acceptable individual edits, eh? I think your assessment is not based upon what you see here. Brews ohare (talk) 17:56, 21 August 2010 (UTC)

A case of the roadgrader calling the bulldozer yellow? Your edits that they revert and comments that they ignore are indeed reminders of problems at so many other articles. When you don't get your way, you crank up the volume of edits until you overwhelm the opposition, or get taking to dispute resolution. Try to work with other editors more directly, collaboratively instead of confrontationally, and more maybe it won't come to that. Dicklyon (talk) 14:29, 22 August 2010 (UTC)

Hi Dick: Well, I see your point. However, putting it all on me is a bit much. Part of the problem is that responses that don't address the point tend to create elaboration of the point in the (forlorn) hope that it will get through. Our personal interactions are often different: we don't agree on the purpose and scope of WP, which is a personal matter of conception and never can be resolved. It is my view that this fundamental difference between us leads to your actions more than any other cause. Brews ohare (talk) 14:43, 22 August 2010 (UTC)

I disagree. There are not two different, and by implication equally valid, views on the purpose and scope of WP. There is WP's purpose, which almost all editors agree on, or if they don't agree with everything respect enough to work here. And there are your incorrect views which diverge so much from WP's purpose that they become disruptive. They also can be resolved - that is what arbitration is for and why you are currently under editing restrictions. But this has had limited impact on your behaviour so it is under consideration at arbitration again.--JohnBlackburne^words_deeds 15:19, 22 August 2010 (UTC)

Well, John, as is your wont, everything is clear cut, very simple, and of course, totally unspecified. what is that exact purpose of WP that has no nuance and no room for interpretation? And how do my actions impinge upon that conception, exactly, so as to cause your unending attention? Brews ohare (talk) 15:56, 22 August 2010 (UTC)

Definition of matter

I realize that I'm bringing up a sore topic here. However, it is definitely ridiculous to retain a Newtonian definition of matter such as "anything that has mass and volume." This is especially true now that the very definition of space is becoming a hot new theoretical topic. Additionally, even Einsteinian views of relativity would render this definition as obscure and maybe even unnecessary, seeing as light also has effective mass ($E=mc^{2}$), and volume by definition is the occupation of space.

Instead, I would suggest we go along with a variation of Pauling's definition:

"[Matter is] any kind of mass-energy that moves with velocities less than the velocity of light."

In General Chemistry, Pauling was specifically contrasting matter to light, or radiant energy, so this definition would be overly confined in an article solely concerning matter. However, the actual idea can be used to formulate a more precise definition for this article by synthesizing this articles definition with Pauling's. I suggest the following:

"Matter is any kind of mass-energy that occupies space and moves through it with velocities lower than the speed of light."

☲Fireyair☲ (talk) 03:35, 11 February 2010 (UTC)

You are arguing from the assumption that there is one single correct definition of matter. In particular you are arguing that that definition should be formulated to explicitly exclude light, while there is a significant community (mostly people working in GR or cosmology) that would count light as a form of matter. They basically define matter as "anything that causes spacetime curvature."TimothyRias (talk) 07:20, 11 February 2010 (UTC)

I am not suggesting to define matter in that sense. The very idea of defining matter is through the implication that it significantly different from the only other form of energy in the universe; that is, light. Matter has always been defined as opposed to light. It is perfectly obvious from Einstein that matter and light are manifestations of the same central element. However, matter by definition is that which acts differently from light. Of course you can define light as matter, or matter as a light: they are one and the same after all!Think of it this way: if light were a type of matter, then the so called "speed of light" would actually be a speed of matter. Yet we still claim that matter cannot travel at the speed of light! Obviously, there is an emergent difference between energy manifested as light and energy manifested as matter. Whether this difference is intrinsic becomes an irrelevant philosophical issue. It's like distinguishing between a substance in the solid phase and one in the liquid phase. ☲Fireyair☲ (talk) 22:39, 15 February 2010 (UTC)

You are still arguing that we need to adopt a single definition of matter as the "correct" definition in this article. That would be a violation of NPOV, since there are different equally valid definitions. Sometimes the term matter is used to distinguished from light, at other times matter is used to distinguish from spacetime and includes anything that "exists in spacetime" including light. The latter definition by the way is much closer to Aristotle's concept of matter. (His context was the discussion whether empty space was nothing). TimothyRias (talk) 08:02, 1 March 2010 (UTC)

I acually think the main thing to know about the term "matter," is that it doesn't have a good scientific definition, and any reader needs to start from THAT fact. When you use the word, you may think you know what you're talking about, but many others will not, so stay away from it. After we get that essential problem out of the way, we can talk about some history and some suggested definitions by various people, and then leave it as one of those words that isn't nearly as useful as many laymen probably thought it was. SBHarris 00:49, 11 March 2010 (UTC)

I completely agree. It would be an enormous help for this article if we could find a source that makes exactly that point. Otherwise, we are somewhat in a shady WP:SYNTH area with citing multiple sources providing incompatible definitions. TimothyRias (talk) 09:24, 11 March 2010 (UTC)

I can only observe that dispite WP:SYNTH, a certain amount of synthesis is unavoidable in writing WP articles, and this is of that sort. If there are a number of views out there, the entire job of the encyclopedist is to summarize, present, and synthesize them into an article! Anything else would be somebody else's encyclopedia article, and plagiarism. I don't think it's any more unwikipedian to say that there are a number of different non-compatible views on the definition of matter, any more than any other routine job we do when writing an article (or a dab page, or a many-part definition on Wikionary). SBHarris 02:38, 14 March 2010 (UTC)

I agree, it is somewhat unavoidable. Still it would be a great help for the article if there was an authoritative source backing the statement that there isn't a good scientific definition. Otherwise, you will keep on having authors arguing that there is one correct unifying definition, of which the others are just special cases, etc. But if we can't find such a source then we clearly have to fall back on the next best thing. TimothyRias (talk) 09:47, 15 March 2010 (UTC)

To avoid a nonce introduction here, I took a crack at writing a basic definition:

..and simply put, refers to the atoms and any particle which has mass, or to any subatomic particle (as a constituent of an atom) regardless if it itself has mass or not.

The ways by which things are conceptualized evolves over time, and thus occasionally present contradictions, but from an explanation point of view, its more important to associate matter -> mass, than it is to explain how in cosmological terms, even light has cumulative effects on curvature, and so on. Important, certainly, but perhaps also an abuse of the term "matter." -Stevertigo (w | t | e) 16:46, 16 June 2010 (UTC)

Lede

Trias' new lede is quite good. But the passage: "A common way of defining matter is as anything that has mass and occupies volume" - needs perhaps a little more detail, as "volume" is rather a strictly 3-d concept that, while simple, does not typically indicate what its ultimately talking about, which is dimension. -Stevertigo (w | t | e) 19:00, 18 June 2010 (UTC)

Defining matter

The Penrose approach “Matter is that which comprises physical objects – the “things” of the world” appears in this version of the article. It is a bit vague, but that isn't bad considering the long evolution of the concept described in the history section and the extensive discussion of definitions in the definitions section. It seems useful to have a lead-in formulation that can encompass all the later discussion and definitions.

Although the mass and volume definition is widely quoted, I believe the just-mentioned sections in this article very clearly establish that the popular meaning is not satisfactory for many purposes. For one thing, it is pointed out in the quarks & leptons section that mass attaches to particles that are not matter. The turn of the century history section makes clear that this mass and volume definition lost its authority some time ago, being incomplete at best, even in the late 19th century.

For these reasons, IMO the mention of this definition in the intro is simply to reflect common usage, but it shouldn't suggest in any way that this definition has any more solid support than being a popular conception.

Thus, I support this version. Brews ohare (talk) 14:36, 6 August 2010 (UTC)

Our job is to reflect what is 'widely quoted' rather than one editor's opinion as to the truth ... abtract whose keyboard is capput

Hi Abtract: Well, that's part of the job anyway. And it is one thing to point out the commonly used definition, and it is another thing to venerate it.

However, I'm learning with these things that sometimes they can be changed for a short time because nobody is looking, but anything that attracts more than a couple of editors is a lost cause. The careful deliberations of the past are forgotten, the hair splitting is water under the bridge, the beautiful resolutions of detail are a thing of the past. So fogetaboutit, that's my motto. Brews ohare (talk) 01:00, 7 August 2010 (UTC)

Problems arise when multiple sources make conflicting statements. In that case, ideally we find an authoritative source that deals specifically with the different views. If no such source is available, then we are left with trying to assert which source is more authoritative. In this case I'd say that the Penrose reference is much more authoritative than the statement in a condensed matter physics textbook since the latter is: a) written by a less prominent author b)deals with a limit context 3) for an audience with limited knowledge. (In the later source a discussion of matter in a context of quantum physics and relativity would be a hopeless digression which its audience would not be expected to follow.) As such, I see a strong case for putting the admittedly vague definition of Penrose first, quoting the volume/mass definition later as a common example of a more exact but not universal definition of the concept.TimothyRias (talk) 10:51, 7 August 2010 (UTC)

Some suggestions for improvement of this page.

Here are some ideas for how this page could be improved in general:

• Increase focus on the structure and properties of matter rather than the definition. The definition of matter is typically vague. This makes it hard to say something about the topic within WP guidelines. A general reader coming to this page, will however be less interested in esoteric discussions of how exactly matter is defined, then just hearing about its properties.
• The "Structure of matter" section could be restructured to have more of a large to small scale flow. That is start with the structure compounds, a move to increasingly fine structure like molecules, atoms, subatomic particles, etc. This has the advantage of starting with material that is fairly accessible and slowly moving to more involved theories, leaving space at the end to discuss speculative ideas about even finer structure of matter. (Like strings)
• Much of the material in some of the definition subsection about building blocks, probably would be better at home in the structure section.
• The phases section has become a long laundry list of different possible phases. This article is not about phases however, we have a dedicated article for that phase (matter). This section should be brought down to a more concise and to the point summary of the phase (matter) article.

TimothyRias (talk) 15:00, 18 August 2010 (UTC)

Sounds good. Need any help? Sebastian Garth (talk) 16:32, 18 August 2010 (UTC)

The only problem with the "building blocks" or "particulate theory" is that it includes only ordinary matter. However, in its favor, it describes the entire history of the topic up to the introduction of dark matter and dark energy, which is still a very mysterious topic. In other words, we have many centuries to attest to the power and fascination of the "building block" concept. As such, the "building blocks" approach makes a good framework for the various segments of the article, and it is nicely organized around this idea. A different organization around "structure and properties" at this stage is a "gleam in Timothy's eye" and needs to be fleshed out here to show it has some organizational capacity. Brews ohare (talk) 17:45, 18 August 2010 (UTC)

Dark matter is assumed to made out of "building blocks" just like any other type of matter. The building blocks of dark matter are different then from "ordinairy matter". Dark energy is slightly complicated as its nature is completely unknown. For example, it may turn out that it takes the form of a pure cosmological constant and should be considered part of the gravitational sector of the theory rather than part of the matter sector. If it is to be part of the matter sector then it is likely to have building blocks as well.TimothyRias (talk) 22:51, 18 August 2010 (UTC)

I've gone ahead and made a beginning with some of these improvements.TimothyRias (talk) 20:34, 23 August 2010 (UTC)

Archive discussion from Brews at Talk:Matter/Archive 2

I've taken the liberty of archiving the recent brouhaha. These were massive walls of text that didn't contribute much to the improvement of the article, and consisted discussions of Brews with himself for the most part anyway. Since these detracted from improving the article, and there's little point in continuing a discussion with someone who can't reply (he just got topic banned for a year, again), I've archived them.

If you think some of the issues he raised have merit, feel free to start a new thread. After all, the point of this archiving is not censorship, but rather to give a fresh start. The old discussions can be found at Talk:Matter/Archive 2 for everyone to browse at their leisure. Headbomb {talk / contribs / physics / books} 17:43, 22 August 2010 (UTC)

Some suggestions for improvement of this page.

Here are some ideas for how this page could be improved in general:

• Increase focus on the structure and properties of matter rather than the definition. The definition of matter is typically vague. This makes it hard to say something about the topic within WP guidelines. A general reader coming to this page, will however be less interested in esoteric discussions of how exactly matter is defined, then just hearing about its properties.
• The "Structure of matter" section could be restructured to have more of a large to small scale flow. That is start with the structure compounds, a move to increasingly fine structure like molecules, atoms, subatomic particles, etc. This has the advantage of starting with material that is fairly accessible and slowly moving to more involved theories, leaving space at the end to discuss speculative ideas about even finer structure of matter. (Like strings)
• Much of the material in some of the definition subsection about building blocks, probably would be better at home in the structure section.
• The phases section has become a long laundry list of different possible phases. This article is not about phases however, we have a dedicated article for that phase (matter). This section should be brought down to a more concise and to the point summary of the phase (matter) article.

TimothyRias (talk) 15:00, 18 August 2010 (UTC)

Sounds good. Need any help? Sebastian Garth (talk) 16:32, 18 August 2010 (UTC)

The only problem with the "building blocks" or "particulate theory" is that it includes only ordinary matter. However, in its favor, it describes the entire history of the topic up to the introduction of dark matter and dark energy, which is still a very mysterious topic. In other words, we have many centuries to attest to the power and fascination of the "building block" concept. As such, the "building blocks" approach makes a good framework for the various segments of the article, and it is nicely organized around this idea. A different organization around "structure and properties" at this stage is a "gleam in Timothy's eye" and needs to be fleshed out here to show it has some organizational capacity. Brews ohare (talk) 17:45, 18 August 2010 (UTC)

Dark matter is assumed to made out of "building blocks" just like any other type of matter. The building blocks of dark matter are different then from "ordinairy matter". Dark energy is slightly complicated as its nature is completely unknown. For example, it may turn out that it takes the form of a pure cosmological constant and should be considered part of the gravitational sector of the theory rather than part of the matter sector. If it is to be part of the matter sector then it is likely to have building blocks as well.TimothyRias (talk) 22:51, 18 August 2010 (UTC)

I've gone ahead and made a beginning with some of these improvements.TimothyRias (talk) 20:34, 23 August 2010 (UTC)

Archive discussion from Brews at Talk:Matter/Archive 2

I've taken the liberty of archiving the recent brouhaha. These were massive walls of text that didn't contribute much to the improvement of the article, and consisted discussions of Brews with himself for the most part anyway. Since these detracted from improving the article, and there's little point in continuing a discussion with someone who can't reply (he just got topic banned for a year, again), I've archived them.

If you think some of the issues he raised have merit, feel free to start a new thread. After all, the point of this archiving is not censorship, but rather to give a fresh start. The old discussions can be found at Talk:Matter/Archive 2 for everyone to browse at their leisure. Headbomb {talk / contribs / physics / books} 17:43, 22 August 2010 (UTC)

Vacuum first or matter

WP:NOTFORUM TimothyRias (talk) 11:57, 27 September 2010 (UTC)

The vacuum (spacetime) tend to be continuous and homogeneous with regard to its energy (vacuum energy)--e:Y,?:G 17:51, 26 September 2010 (UTC) and composition. Matter forms within vacuum. When matter forms, curvature in spacetime starts (or simultaneously)--e:Y,?:G 17:53, 26 September 2010 (UTC) to form (accumulate) around the forming, formed matter. Because matter took the space that it (matter) occupies form space by pushing outward spacetime. We should always think of density with regard to matter in vacuum, space,spacetime where vacuum, space, spacetime exerts an inward forces on matter i.e. universic pressure. Relative density of matter in spacetime= density of matter/density of vacuum where density of vacuum= vacuum energy/ volume. Relative density of matter in spacetime and universic pressure,are the origins of gravitational forces, if, with our without, the following could be true, at: {vacuum energy = Ev ≠ M C^2 and Ev < M C^2} the Ev < M C^2 and Ev ≠ M C^2 is to express a condition, a limit for the relative density of matter to operate, to be valid within the wave form energy value is isolated from the particle form energy value, duality of matter, even if it was very small in time, creating an oscillating gradient of mass concentration, to obtain the vacuum energy value only with no mass, to isolate the energy values of vacuum from matter as much as possible and if possible. --e:Y,?:G 17:45, 26 September 2010 (UTC) —Preceding unsigned comment added by E:Y,?:G (talk • contribs) --e:Y,?:G 17:51, 26 September 2010 (UTC)--e:Y,?:G 07:00, 27 September 2010 (UTC)

I have reverted the recent edits removing quark and leptons definition etc...

There's absolutely no reason to remove these at all. These sections were well sourced, well explained, etc... Why anyone would remove them is simply beyond me. Headbomb {talk / contribs / physics / books} 23:54, 23 December 2010 (UTC)

I've left them be (I didn't take them out in the first place), but in the process of reverting, you ended up reverting some work in which I point out that the matter definition needs careful work to avoid confusing it with mass (which was completely the case in the relativity section of this article). We agree what whatever matter is, it must have mass. However, matter particles are a subset of massive things, as there are many kinds of mass that are NOT matter (at least not by the lepton definition). If I heat an object, I add mass to it without adding a single lepton. Thus, that extra mass is not matter, by the lepton definition. Confusing mass with matter in the definition, when they are not the same thing, leads to the nonsense where mass is said to be converted to energy, and so forth, which bedevils physics students (and some physics professors) to this day. For example, the mass that an atom bomb loses, is not matter, either. Leptons are conserved when an atom bomb goes off, but some of the mass of the bomb goes elsewhere. Whether "matter" is conserved when an atom bomb goes off is a question that is sort of meaningless. When you speak of matter as being "leptons", are you speaking of their NUMBER only? Or the sum of their weights and masses? What? Defining matter as leptons doesn't solve the qualitative problem. In a bomb, some non-matter energy in potential energy fields, is converted to non-matter energy that is kinetic energy. Matter, I suppose, is conserved in this case. But in an antimatter bomb, it would not be! Mass and energy, yes (as always). But matter, no. Antimatter and matter are converted to nonmatter, and that's it. SBHarris 01:39, 24 December 2010 (UTC)

SBHarris - I have reverted your changes, as I found them to be confusing and somewhat inaccurate. Your phrase "matter-types are is only a subset of types of mass" is impossible to understand - what are "matter-types" ? When you say "mass is generally conserved in physics, just as energy is, and neither mass nor energy may be created or destroyed (or converted into one another)", this is wrong - mass is energy and energy is mass - there is no separate conservation of one or the other. And I think your rewrite of the "Relativity" section will need a reliable source - at the moment, it reads like your own POV interpretation. Gandalf61 (talk) 10:01, 24 December 2010 (UTC)

Matter-types are only a subset of types of mass was meant as a restatement of the idea that all matter has mass, but not all mass is matter. One is a subset of the other, in a way, although not all the mass in a lump of matter is represented by particles (some of it is kinetic energy, for example, if the object has a temperature). And some of it is virtual bosons.

That said, you're completely wrong about there being no separate conservation of mass and matter. There is: they are separately conserved. If they are the same thing (which in a way they are) they MUST be separately conserved (that means conserved over time, for closed systems, and for a given inertial observer), since you're just switching labels (or dividing by c^2, if you like). In a closed system when a positron and electron anihilate into two gamma rays, mass is conserved thoughout the process (the two gamma rays as a system continue to have a mass of 1.022 MeV, which is the invariant mass of the system). But matter is not conserved. Two matter particles are now two particles (photons) that Headbomb refuses to consider matter. And all of this is not based on something as arcane as calculating the invariant mass of a 2-photon system. A positron can be wandering around in a large lump of lead metal. What happens when it finds an electron and annihilates, if the two gammas happen to be absorbed and turned into heat inside the metal lump? Answer: matter disappears (is not conserved), for two particles have now disappeared, that were present before. But MASS is conserved, since the 1.022 MeV of heat generated in the lump increases the MASS of the lump by just the amount of the (now missing) mass of the missing electron and positron, so it all stays the same (on a scale, it would weigh the same, before and after the annihilation). So MASS is separately conserved, AS ALWAYS, in a closed system.

So you see, when talking about the difference between "matter" and "mass" we need to talk about conservation laws. They don't apply to matter, but they do apply to mass. And we cannot confuse matter and mass, which is what the relativity section I fixed, formerly did (it was talking about mass in an article about matter).

As for my sources, all this is Taylor and Wheeler's Spacetime Physics, which I've been using as my textbook source for the relativity articles. I can move some of those over, if you like. But if you disagree with what I've said above, I'm afraid your problem is with understanding of basic physics, not lack of sources. You should be (at this point) just nodding your head in agreement with my examples, but wishing that I'd merely expressed myself better when explaining them. In which case, feel free to try it yourself. The LEAD/LEDE as it is now, doesn't differentiate matter from mass, which means if you don't rewrite it, you have no argument for not deleting this entire article, and redirecting "matter" to the article on "mass". So think about it. SBHarris 21:31, 24 December 2010 (UTC)

There is a simple distinction mass is a quantity. It is a property that objects, particles, systems, etc. can have. Matter, on the other hand is not a quantity it is an abstract concept, like "light", "wave" or "radiation". As such a statement like "matter is (not) conserved" is meaningless.TimothyRias (talk) 15:22, 4 January 2011 (UTC)

I agree with Gandalf here, I couldn't make any sense of most of section. Headbomb {talk / contribs / physics / books} 12:04, 24 December 2010 (UTC)

Yes, the original wording was much clearer, IMO... Sebastian Garth (talk) 15:04, 24 December 2010 (UTC)

The problem with these sections is that they pretend that they are sourced, but nowhere do the cited sources support what is being said. The sources typically contain statements like matter is made up of X, Y, and Z made in a context of explaining the structure and properties of matter. Such a statement are not meant as a definition, and the sources provide no basis for turning the statements into definition. It is impossible to conclude from such a statement that anything that consists of X, Y, and Z is matter. (It is logically possible from the statement that there are things which consist of X, Y, and Z and are not matter.) Inferring that anything that does not consist of X, Y, and Z is not matter according to the source is synthesis and may not even be true; the author simply may not have been considering such cases as they were irrelevant to the context.

A lot of what currently is being said in theses sections should just be said in the "structure of matter" section without artificially trying to turn it into a definition. The "Definitions" section should then only contain a short paragraph the in certain situations matter is defined as stuff with a certain structure. The only documented case of which I know is that distinction made of leptons and quarks being matter fields in contrast to gauge bosons being considered forces. (We still need to find a reliable source that actually says that, though.) TimothyRias (talk) 15:16, 4 January 2011 (UTC)

I don't really see what you mean. The article covers the progression of the "building blocks" picture of things, moving from "atoms" to "quark and leptons".

Yes, and we're nowhere closer to resolution of the problem that matter is said to be made of quarks and leptons, even though they only constitute 2% of the mass of a lump of ordinary matter, like an apple or a human being. It's fine with me if the authors of this article insist on defining matter in this fashion, but the "paradox" that most of the mass in matter is not what they define as "matter," needs addressing in the lede. As also (as I said) the fact that mass by all standard definitions in physics is conserved, whereas matter is not. I have been stymied in trying to add this to this article by Headbomb, who has essentially said that his personal definition of "mass of a system" (the sum of rest masses of its parts) is NOT conserved. So now I'm having problems with not one, but TWO of Headbomb's personal definitions in physics, one for "mass" and the other for "matter." I'm getting tired of it. SBHarris 20:41, 5 January 2011 (UTC)

SBharris, you should really get a clue. None of what is found here are my "personal definitions". It's you who fail to speak the same language as everyone else, and the "paradoxes" you speak of are only your own because you equate matter with mass, something which is inappropriate at small scales. If you read what was written, you'd have seen this. Mass is not a conserved quantity, which is what E² = pc² + m²c⁴ is all about. If you have electron and positrons before (sum of masses = 1.022 MeV/c²), and two photons after (sum of masses = 0 MeV/c²), mass is obviously not conserved. No one cares about the invariant mass (E_tot/c²) of the system, at least not directly. Because care about Energy and conservation of energy. Your argument is that since the "sum of masses" is not a conserved quantity and is thus "meaningless" is a tautology, because you defined "meaningful" as "a quantity that is conserved". There are several definitions of "matter", and in particle physics, matter is not equated with mass. In particle physics, matter is seen as building blocks, and these building blocks (elementary fermions) have associated properties and are surrounded by bosonic fields (gauge bosons). This is all discussed in the article, with both the explanation for this distinction between matter and fields, and the scope and limitation of this particular definition of matter. This is one of several definitions of matter, all of which are covered in the article. Headbomb {talk / contribs / physics / books} 02:14, 6 January 2011 (UTC)

Yes, the definition of mass as “the sum of masses” is your personal definition of mass. Nobody else uses it. We both agree that “the sum of rest masses” is not conserved, and you give an example where it isn’t. So what? And where did you define mass as the “the sum of rest masses”? You defined it that way, when you stated that mass is not conserved and gave this kind of example as to why it isn’t. Unless you define mass as the sum of rest masses, it IS conserved.

Yes, I defined “meaningful” as a quantity which is conserved. But that includes invariant mass. Although you claim “no one cares” about invariant mass, it is a widely used concept in physics, partly because it is E_tot/c² only occasionally. E_tot/c² is actually the definition of relativistic mass, not invariant mass. It’s only invariant mass in the special case when the system momentum is zero and the two types of masses are the same. That is why the weight of systems (a bottle of hot gas or a hot object) is equal to their total energy: the reason is that the weight is connected to the system invariant mass, not that the weight is connected to the total energy. However, if you’re weighing a system its momentum must be zero, so they (the total energy/c^2 and the invariant mass) happen to be the same number, so that causes confusion.

You write “mass is not a conserved quantity, which is what E² = pc² + m²c⁴ is all about.” Answer: What?? That equation shows that if energy and momentum are conserved, then mass must be also! It’s simply the relationship between total energy, invariant mass, and momentum. A better look at it is: m² = E² –p. It simply says that the mass (rest mass or invariant mass for systems) is the Minkowski norm of the E,p 4-vector. All of these quantities happen to be conserved. E and p are not invariant (their values depend on the frame of the observer), but you can’t tell from that fact whether or not they are conserved over time. As it turns out, each of them (E and total p) separately is conserved over time, for any given observer in any given frame. The mass given in this equation, in addition, is invariant (that is, changing frames makes no difference to the amount of it an observer sees), and since mass in this equation is the length of a vector defined by the difference of 2 conserved quantities, it also must be conserved. In addition (since it is a Lorentz-invariant 4-vector) it is independent of the observer frame, which neither momentum or energy are. So, not only is the mass as conserved a quantity as energy and momentum, but mass as defined in this equation has invariant properties which neither energy or momentum do. Which is not surprising, I suppose. SBHarris 03:37, 7 January 2011 (UTC)

I should add, by the way, that the "sum of masses" IS conserved, if you define it in any fair way, which is the sum of masses as seen by any single observer, over time. The reason "sum of rest masses" is not conserved, is that each rest mass is measured by a different observer (one at rest with respect to that mass) so you're adding a bunch of quantities collected from different reference frames. You can't expect any quantity to be conserved if you're allowed to measure it in THAT fashion. Since such a proceedure doesn't "see" kinetic energy, even energy is not a conserved quantity if you look at it, in that way. If you can't apply that procedure even to energy, it's certainly not fair to apply it to mass, and then when it fails, claim that mass is not conserved. The problem is not with the mass, but implied idea of how to measure it. SBHarris 19:24, 7 January 2011 (UTC)

Building blocks cites

• However, currently the article does not cite a RS for such a "building blocks" definition.TimothyRias (talk) 06:39, 6 January 2011 (UTC)

Yes it does. There are plenty, many even directly quoted ("Carithers and Grannis state: Ordinary matter is composed entirely of first-generation particles, namely the [up] and [down] quarks, plus the electron and its neutrino." [1] ). Others sources, such Olmsted and Williams [2] (pages 40-56 are particularly relevant) and Davies ([3], p.2 "The quarks and lepton [...] could well be the ultimate building blocks of all matter") are also given. There are several more also present in the article

• B. Povh et al., page 2.:

  Leptons and quarks. The two fundamental types of building blocks are the leptons, which include the electron and the neutrino, and the quarks.

• B. Carithers and P. Grannis, page 7. (Currently ref 22/23):

  With these discoveries, and through the development of the Standard Model, physicists now understood that matter comes in two parallel but distinct classes—quarks and leptons.

• K. A. Peacock, page 125:

  The Standard Model says that matter and energy are described in the language of quantum gauge field theory. All particles are divided into fermions and bosons. The field quanta are bosons, and they mediate forces between particles of matter, which are fermions.

• G. Fraser, page 92:

  Establishing the quarks and leptons as the basic bits of matter is only part of our revolution...

Headbomb {talk / contribs / physics / books} 09:24, 6 January 2011 (UTC)

All interrupt here for second. None of those quotes support any definition. I'll try to illuminate the problem with an analogy:

In a textbook about modern printing techniques you might find a quote like:

"The fundamental component of a book is paper."

However, you could not use such a quote to source the claim:

"Books are defined as those things that are made out of paper".

First of we know that there are plenty of things that are made out of paper, which are not books. Moreover, there are also books that that are made from other materials like parchment. The statement "The fundamental component of a book is paper." is simply a statement about books (within a certain context: printing), with the author assuming that the reader has an idea what is meant by the word "book".

A similarly, above quotes simply say something about matter and are not trying to define it. In fact, in many cases it is the opposite, the quote is trying to define the mention building blocks in terms of a presumably known concept "matter".TimothyRias (talk) 10:05, 6 January 2011 (UTC)

Even more directly, current ref 29 reads.

The history of the concept of matter is a history of the fundamental length scales used to define matter. Different building blocks apply depending upon whether one defines matter on an atomic or elementary particle level. One may use a definition that matter is atoms, or that matter is hadrons, or that matter is leptons and quarks depending upon the scale at which one wishes to define matter.

B. Povh, K. Rith, C. Scholz, F. Zetsche, M. Lavelle (2004). "Fundamental constituents of matter". Particles and Nuclei: An Introduction to the Physical Concepts (4th ed.). Springer. ISBN 3540201688.{{cite book}}: CS1 maint: multiple names: authors list (link)

Headbomb {talk / contribs / physics / books} 09:24, 6 January 2011 (UTC)

Such a statement would in contrast to the others be a good source for a statement about a building blocks definition. However, despite my best attempts to find it, I have not been able to find that quote in that book.TimothyRias (talk) 10:05, 6 January 2011 (UTC)

Strike that last one, it's a note, not a quote. Headbomb {talk / contribs / physics / books} 10:12, 6 January 2011 (UTC)

So were back to the situation that we do not have sources for the statements that:

1. Matter can be defined as that which is made of atoms and molecules.
2. Matter can be defined as that which is made of protons, neutrons, and electrons.
3. Matter can be defined as that which is made of quarks and leptons.

TimothyRias (talk) 08:50, 10 January 2011 (UTC)

Improvements needed to Late nineteenth and early twentieth century

This section is a a mess of generalizations. Someone needs to go through and either delete the generalizations or expand them. Also, unless my history is way off, quarks are late and not early 20th century. Some sentences later in the section read not like a careful discussion of the history of ideas, but as if written by a fan breathlessly excited by reductionistic advances in science. JKeck (talk) 21:16, 23 March 2011 (UTC)

Care to have a go?TR 08:55, 24 March 2011 (UTC)

Yes there's an overlapping problem between the "Late 19th/Early 20th" and the "later developments" sections. I don't really know how to fix this though. Headbomb {talk / contribs / physics / books} 11:48, 24 March 2011 (UTC)

I'm taken an initial stab at cleaning it up, but there's plenty of work left to do. The sections after the Chomsky quotation need to be an historical outline actually drawn from a book (Levere's or whoever's—might I recommend Toulmin & Goodfield's The Architecture of Matter?) and not simply be a Frankenstein's monster of individual sentences contributed hit-and-run. JKeck (talk) 23:34, 24 March 2011 (UTC)

Definition of Matter

Why is it thought to be necessary to define matter as having both mass and occupying space ? Surely the first requirement is adequate. Am I missing something or is there some form of substance or entity which has mass but does not occupy space and which is not considered to be matter ? Or is it the case (as I suspect)that all entities or substances which have mass also occupy space ? —Preceding unsigned comment added by 82.46.13.64 (talk) 18:02, 17 May 2011 (UTC)

Well, photons have mass when they present in pairs not traveling in the same direction (like the pair of photons from a matter-antimatter anihilation, or the pair from a neutral pion decay). But photons don't really take up space and are thought to have no intrinsic "size." On the other hand, electrons are commonly considered to be matter, and they are (in the limit of experiment) "point particles" also. They take up "space" only by virtue of the Heisenberg principle. But that applies to photons, too. Ultimately, "has mass and takes up space" is not really a very good definition of matter. But "matter" doesn't really HAVE a good definition. It's a concept that was invented to describe things on the atom-level, and it increasingly breaks down for subatomic particles, which have some characteristics of atoms (like volume) and sometimes (as in the case of electrons) do not. SBHarris 18:19, 17 May 2011 (UTC)

I'd like to promote the inclusion of a book by Dr. Gustave Le Bon on "The Evolution of Matter", Wherein he says"It would, no doubt , be possible for a higher intelligence to conceive energy without substance, for there is nothing to prove that it necessarily requires a support; but such a conception cannot be attained by us. We can only understand things by fitting them into the common frame of our thoughts". That sounds like a pretty good summary of the situation and was written prior to 1907.WFPM (talk) 18:02, 11 February 2012 (UTC)

I can easily conceive of energy without substance as I understand "substance." A light beam. Or the electrostatic field around a charge. A magnetic field around a magnet. Ripples in a gravitational field. All examples of energy without matter (or substance as we understand the word). Look, WFPM, our problems with the word "matter" are not going to go away because you or some author of more than a century ago, replace "matter" with an equally poorly-defined English term like "substance." No help, I say. SBHarris 19:16, 11 February 2012 (UTC)

Appreciate the comment! So you have a concept of forces without substance. So you're like Yukawa and have to create a particle that goes out and tells another particle that it's "attracted" in a certain direction due to the existence of some non-substance electrostatic or electromagnetic field. Well, how about when you swing a pendulum magnet through an arc toward an opposing magnet at the bottom of the arc, and hear the click of the impact of the two forces and see the pendulam magnet bounce away, and you say there no substances involved. What do you think is interacting in those cases? And I,m pretty sure his connotation of the word substance is the same as of the word matter.WFPM (talk) 20:21, 11 February 2012 (UTC)

And in his book "General Chemistry" ISBN O-486-65622-5 (page 45) Dr Linus Pauling describes the interaction of electrons with a magnetic field as being unexplainable and just a description of activities in "a part of the world in which we live". And his book hasn't been referenced either.WFPM (talk) 15:44, 13 February 2012 (UTC)

But of course, where there is a will there is a way. And in 1992 in his book "Atom" ISBN 0-452-26834-6 (page256) Dr Isaac Asimov explains Yukawa's concept of rapid exchange particles as a way of propagating forces of attracting and repulsion in a way I can almost understand, but not quite.WFPM (talk) 16:10, 13 February 2012 (UTC)

Is this article confusing the notion of relativistic mass with rest mass?

We have this sentence,

"By contrast, massless particles, such as photons..." which uses the modern definition of mass where photons are mass-less. But then there is this "For example, mass is a conserved quantity, which means that its value is unchanging through time, within closed systems" which is using the relativistic notion of mass, which in my education we learned is a depreciated way of looking at things.

These sentences seem to me to be a direct contradiction. If mass is truly conserved then we have to consider the photon to be a massive particle. This is the old way of looking at things, were distinctions are made between rest mass and relatistic mass. If we consider the photon to be mass-less, as it is usually defined in modern times, then mass is not conserved.

Per Noether's theorem, symmetries produce conserved quantities like energy and momentum. There is no symmetry that entails conservation of mass, is there?

ModusPwnd (talk) 23:58, 20 May 2013 (UTC)ModusPwnd

There are two types of energy and two types of mass. Rest mass and invariant mass (together constituting one type) are both conserved (they stay the same for any observer, though time). They are also invariant (their value is the same for any observer). Photons have no rest mass, although one or more photons moving in different directions do have an invariant mass, as a system (even though each is individually massless). Divide any of these quantities that have mass by c^2 to get rest energy (of course for single photons you divide zero by c^2 and get a rest energy of zero).

The other type of mass, relavistic mass, is simply E/c^2 and is deprecated because you might as well use total energy. Single photons do have relativistic energy and mass. Relavivistic mass is also conserved in time for any given non-accelerated observer (which is what "conserved means), even though different inertial (galilean reference frame) observers disagree as to its absolute value (for a single photon it can be anything you like).

It's difficult for many people to get used to the idea that a single photon added to a box increases its (rest) mass on a scale, even though the photon itself has no mass. But that's because you're weighing the photon-box system, which has zero momentum, and so its rest energy is equal to its total energy and its rest mass is equal to its relativistic mass. These matters are more deeply explained at mass-energy equivalence.

And by the way while mass is a conserved quantity, MATTER is not. Which is the whole point of addressing this in this article. If you have an electron annihilate a positron in a box, the two (massless) gamma rays will bounce around inside the box and its mass (on the scale) won't change! That's because as a system, the two gamma rays still have two electrons' worth of mass! WHich you can weigh when they are trapped. But of course, they are no longer matter. SBHarris 00:27, 21 May 2013 (UTC)

But a scale doesn't measure mass, it measures force. The photon's energy contributes to the gravitational force. They have no mass. Mass-energy equivelence doesn't mean energy is mass, it means they are equivalent. This is how I was taught and this is how I teach my students. There is no conservation of mass, that is an approximation that does not strictly hold. If it did, there would have to be a symmetry associated per noether's theorem, but there is not... is there? Photon's are massless. A system of photons is massless. They are subject to the gravitational force because of their energy. Otherwise, you are using depreciated relativistic mass and should not call photons massless.

Some links From Harvard-Simithsonian center for astrophysics; http://www.learner.org/courses/physics/unit/text.html?unit=2&secNum=3 From the Physics Forums; http://www.physicsforums.com/showthread.php?t=645599

From Urbana-Champaign; http://van.physics.illinois.edu/qa/listing.php?id=15590

Though I think that Urbana-Champaign link may be making the same confusion between relativistic and rest mass. ModusPwnd (talk) 16:50, 21 May 2013 (UTC)

The measurement of the box of two photons doesn't have to be with a scale, it can be by shaking it (as in zero-g mass measurement). The box has more inertia. And it gravitates more, which is why it weighs more on a spring scale, too. There is no measurement you can do on the outside of box to see if it holds an electron and positron, or the two gammas from their annihilation. And there's a basic reason for this.

Two photons (so long as not moving in the same direction) are not massless but DO have mass, and not just "relativistic mass". See [4] but this is a standard student exercise in SR. This mass (again) is not the deprecated Tolman "relavistic mass" (although it happens to be equal to it, for reasons to be explained). It is (also) invariant mass which is system mass, which is what you weigh or measure. And what has inertia and gravitates. And constructs the Landau-Lifschitz pseudotensor of the system, and so on. In that sense it is "real" and is the only type of energy you can use to construct new particles from in experiments, and so on.

Unlike the energy of a SINGLE photon, which doesn't really have a unique value (depends on who is looking) the mass of two photons has a minimum value which cannot be reduced any further by reference frame-change. This value is in the COM frame, which is the frame where momentum is zero, which means both photons have the same energy (momentum) and are traveling in exactly the opposite direction. In this frame, their invariant mass (and relativistic mass) is 2E/c^2 where E is the energy of either photon. In any other frame the total E is larger, but the invariant mass stays the same (of course) because such a system has net momentum which subtracts from the energy in the E^2 - p^2 = m^2 relation. In the COM frame, E=m. Hence the utility of the COM frame-- relativistic mass, energy, and system invariant mass and energy are all the same there. Relativistic E and m differ when seen in other frames. But they can't be used to make new particles (energy transformed to matter). Only invariant mass can be used for that.

The massiveness of massless fields is a good thing, since most of reality requires it. The equivalence of relativistic mass and invariant mass in the COM frame comes in handy in measuring the mass of systems like-- hadrons. These are composed of massive (but fairly light) quarks moving very fast, but bound in a "box" of a hadron particle (like a neutron or proton). Only 2% of the mass of the neutron or proton you weigh is the rest mass of the quarks inside. The rest (exactly as with the photons in the box above) is the mass of massless fields (composed of photons or gluons), or kinetic energy (which of course has relativistic mass but no REST MASS, since it's never seen in the given particle's rest frame). So 98% of the simple mass of "ordinary matter" is actually due to massless particles or massless kinetic energy of massive particles. But it all shows up as "rest mass" of the confining particles because we measure this in the coumpound particle (system) rest frame, where relativistic mass IS THE SAME AS invariant system mass. Same value. Cool, eh? Therefore: Massless particles add rest mass to systems. Make your students say this many times.

I haven't yet checked out the websites you provided above (no time this second) but I will. These websites and many science teachers, however, screw this all up. Some of the fault of this goes to Tolman and his wacky idea of relativistic mass to keep E=mc^2 always "true." But the rest of the problem is that matter gets confused with mass, as in our box of matter-antimatter or gamma rays. There we have matter disappearing, and matter appearing, and vice versa, but the invariant mass of this system does not change through it all. And if it were confined, both photons and matter would weigh out as rest mass, which also would not change as one was turned into the other.

Blow up an atom bomb in a superstrong box and does its mass change? Not until you let out the light and heat. Until then, it just stays very hot and its mass is constant (shake it and it has the same inertia, weigh it and it weighs the same-- even though full of plasma). But let the light and heat out (cool the particles down, as Feynman would say), and they transfer mass to whatever absorbs them, so you see that the total mass is conserved. Not only relavitistic mass but also invariant mass. And yes, these are both types of energy and so are subject to the energy-time symmetry, as advertised by Noether.

By the way, Taylor and Wheeler in their book on SR, _Spacetime Physics_ get all this exactly as explained above. So this is not some wacky theory of mine own. It's just that (as explained) a lot of even science teachers have not gotten it straight. It's not easy. SBHarris 23:22, 21 May 2013 (UTC)

Well, thanks for the words. I'm still not convinced that this is the best way to look at it, but I do see your points. "There is no measurement you can do on the outside of box to see if it holds an electron and positron, or the two gammas from their annihilation. ".. why does it have to be on the outside? You can open the box. This is how I would determine how much of the inertia/gravitational force is due to massless energy of photons or the energy of mass. There is no need to be able to determine this from a closed box. Shaking is interacting with the system just as opening it is. I would shake the box, note the inertia or weigh the box and note the gravitational force and compute the energy. Then I look inside, see positronium and note the mass. Then I close the box, allow the positronium to decay and shake it and weigh it again. Same inertia, same gravitational force. The energy is conserved. Open the box, no massive particles. Mass is not conserved. Seems simple enough to me.

As you describe, binding energy is more complicated since its certainly associated with matter unlike photons. Would you note the binding energy of the positronium as massive or massless energy? That is a matter of taste I suppose, depending on what you are doing. I wouldn't consider positronium to be matter. Even a heavy atom is tough to call matter, IMO. I think of it as necessarily macroscopic thing, but then it doesnt really matter since matter is not really a scientific term anyway, unlike mass. ModusPwnd (talk) 01:56, 22 May 2013 (UTC)

The problem with your method for defining "mass" is that it discounts "stuff" in the box that acts exactly like any other mass, just because you don't want to call it mass. And it forces you to conclude that the 98% of a neutron and proton (and thus an atom) that isn't massive quarks, is NOT mass. Which means that 98% of the what we weighed (or otherwise determined) was the mass of you and me isn't actually "mass." I opened up the box of my nucleons and found that 2 kg of me is real mass and 98kg of me is fake mass due to being massless field? Now what? This seems not a very good definition for mass. What's the point of it? The whole idea of mass is that it's anything that acts like mass. SBHarris 03:14, 22 May 2013 (UTC)

Not exactly like any other mass. Photons are mass-less and as such they have specific characteristics. Once they are absorbed they are no longer photons. Per the interpretation you put forth, photons should not be called massless right? To be consistent with the description you have described, we need to change the description of the photon and call it a massive particle. How is the description you put forth different than just embracing the notion of relativistic mass and saying that the photon is a massive particle? Whats wrong with defining bound particles to have the mass of their constitutions and their binding energy and considering photons to be massless and thus mass is not conserved? A free electron has a different mass than a bound electron. Does it seem to ad-hoc? I guess that is the weakness of all interpretations. But that is the interpretation I think my education centered around. ModusPwnd (talk) 04:15, 22 May 2013 (UTC)

If you will read [5] you will see that TWO photons do have a mass, and it's not relativistic mass. Nor are they required to be bound. This is real physics; read the paper. There's a lot of discussion of it on the Physics Forum, which tracks what we've said: look at Pervect and Hillman's answers: [6] The fact that two photons has a mass does not mean that ONE photon in free space has a mass. ONE free photon is massless.

Looking at binding energy makes the problem we consider more complicated because binding energy is (by definition) lost from the system, so energy is not conserved when that happens. If you could recover the binding energy from where it went (to a second system B) you would find it equalled the lost energy in system A. Lost binding energy makes mass smaller because energy is lost, and its mass along with it.

A gedanken is helpful. Take a box with 26 free protons and 30 free neutrons and measure its mass. Now. allow the nuucleons to fuse into an iron nucleus (Fe-56). This takes overcoming the EM potentials ala nuclear fusion, but pretend we do it by tunnelling with no energy input. The result is a Fe-56 nucleus which has 99% of the mass of the protons+neutrons. The 1% of mass is now present as gamma rays, given off when the nucleons combined. That is binding energy. So long as you don't let the gammas out of the box, the mass of the box is unchanged. If you let them out into box B, the mass decreases by 1% of the mass of Fe-56, and that's the binding energy. But the mass of box B increases by exactly as much, when it absorbs the gammas, so the mass of binding is/was conserved. It just moved from here to there. In general that's always true. Though occassionally forgotten when the mass is not kept track of. SBHarris 20:45, 22 May 2013 (UTC) From the Physics Forums; http://www.physicsforums.com/showthread.php?t=645599 http://www.physicsforums.com/showthread.php?t=645599 You quoted this thread above and I promised to read it. Did you read to the end? Tom.stoer said the same thing I have said. Invariant mass is conserved, period. The sum of rest masses is not conserved, but nobody ever said it was. Invariant mass is not relativistic mass, it's something else entirely. For systems, invariant mass corresponds to system rest mass, in fact. SBHarris 02:39, 23 May 2013 (UTC)

Any possibility of a better, clearer Introduction? Rewrite recommended.

I find the Introduction, at best, confusing. I am a chemist with some partial understandings of this topic - the entire article is definitely from the physics point of view, obviously. Here is my 2 cents. I tried to confine my comments to the introduction, but find that its weaknesses spill over into the other sections. It is way way too long! The last paragraph seems to be →almost← adequate as an introduction. It recapitulates some of the excess verbiage of the first several paragraphs, but misses some important things (as does the entire intro, I think). One of the first problems I have with the introduction is that is simply not unified. I think it is necessary introduce the "definitions" section along with the explanation that the word is used in different scientific disciplines to mean different things, its use is not consistent, and that there are no accepted definitions of the word (IS it a term?). I argue that there are not 5 definitions (meanings). I think that the section on Relativistic Matter should be removed. Mass (as a substance) is far more likely to be what is meant by the RARE use of the term in discussions in Special Relativity. BUT, I argue that there needs to be a section on Cosmological Matter (possibly including sub-sections on ordinary and dark matter, (bosonic matter covered here if not elsewhere)). Luminous and Nonluminous matter need explanation. Based on the discussions on this page, there are many much more competent than I to do this.

I came to the article looking for the best current value for the amount of ordinary matter in the observable Universe. I am looking for a quantitative mass guesstimate. That should be, it seems to me, a basic piece of information given here. The pie chart has luminous, nonluminous, and dark matter and also dark energy. This really needs to be explained. Where are the photons? Are they all included in the 0.005% radiation component of luminous matter? Just because W/Z bosons have a short life-time, why are they ignored? At any one "instant", is the energy they constitute insignificant? I think the article confuses the levels of abstraction between the Gauge Field paradigm and the Atomic paradigm. NO discussion of matter should ignore energy, yet this article seems to avoid it. Atomic matter is not "usually" composed of electrons, protons, and neutrons - it is ALWAYS composed of them! This is basic chemistry. Yet, I saw nothing about the elements, and a very weak exposition about the building blocks of the Universe (from the chemical pov). Discussing neutrinos, etc. is more appropriate for the sub-atomic, NOT the atomic, paradigm.

So there are four forces in nature (standard model only accounts for 3, right?) Matter and the 3 forces (together with gravity??) needs to be discussed. As far as I understand it (poorly) ONLY the electromagnetic force/field has any significant →non-atomic← contribution to the energy of the Universe. Perhaps neutron stars must be discussed? The article mentions the types of matter, but is inconsistent and not unified. What we see is atomic matter? We can not "see" neutron stars? (Quark-gluon stars?) Degenerate matter?

Basic problem is that the article doesn't have a single voice. All of its problems are tractable. Where in the article does it "explain" the difference between matter and the energy it contains? I understand that the concept of matter as something different from matter+energy is subtle and can't be consistently defined (it varies depending on context). Where is that explained here? — Preceding unsigned comment added by 72.172.11.228 (talk) 21:44, 1 June 2013 (UTC)

COMMENT:

The article doesn't speak with a single voice since long, long ago, somebody from the physics community decided that they "knew" what matter was, and what it was, was fundamental fermions (quarks and leptons). They then wrote the article that way. The problem being that the "guage fields" of these leptons (made of virtual bosons like gluons), are reponsible for 98% of the mass in nucleons, and thus 98% of the mass of "ordinary matter" (stuff made of chemical elements). So it was all confusing. The die-hard finally said he was fine with idea that 98% of the mass of matter is not matter (but is rather something we now define somewhat arbirarily as "energy" due to it having no rest mass), but several of us (including me) thought this was crazy. This gluon stuff DOES have rest mass in systems, like.... nucleons. Some of the nucleon mass is also quark kinetic energy (I have no idea how much). What a pain.

The truth is that nobody really has a good definition of "matter." So a unified presentation can hardly be expected. Perhaps the best way to look at this, is in the last paragraph of the article, not the intro, in which it is pointed out that the word is now almost meaningless, except when used as part of a qualified phrase like "dark matter" or "orginary matter" or whatever. Astronomers tend to use the word his way.

Astronomers do tend to lump the photons in with the "ordinary matter" mostly because it doesn't matter if you do or don't (as you point out). Things like "weakons" (W/Z) are not seen in ordinary matter except as virtual fields, and these don't add much mass.

Less than 1% of the mass of free H is released when it binds into Fe-56 and other elements (where the fraction is less). It's hard to say what this 1% consists of. It's sort of a mix of nuclear force "field" that is destroyed and half as much "mass" of new electric field that is "made" as the positive charges are shoved together in fusion. These fields both have mass since they are energy (one positive one negative, adding to a net negative) but the particles that make up the fields are virtual particles (if they are particles at all) because these fields are static fields. Virtual photons for the increased E field (giving it more mass) and virtual pi's and rho's for the nuclear field (which loses even more mass in fusion than is gained in E field; the reverse for fission). Again, all this is weighable in ordinary matter (iron weighs only 99% of 56 hydrogen atoms), but is this mass "matter"? I dunno.

It's not quite true that "Atomic matter is not "usually" composed of electrons, protons, and neutrons - it is ALWAYS composed of them!" At least if you don't mind defining "atomic matter" as unstable atomic matter (and why shouldn't you-- do we not define radioactive atoms as matter, too?). There are exotic atoms in which chemical matter binds some short-lived lepton or even hadron and what you have before the thing decays, is still matter. Hence the qualification in what you read, although the article on exotic atoms should have been referenced.

Astronomers usually consign gravitational energy to be negative rather than positive, and various experiments suggests that our universe is "flat" and thus very near the "critical ratio" of having just enough negative gravitational energy to balance out the TOTAL positive mass-energy of [ordinary+dark] matter plus dark energy. This assumption is part of what is behind the idea of dark energy, which really only must be 3 times as much as all the rest, which isn't all that much (considering that the ratio of gravity to mass-energy could in theory be anything). Dark energy would have positive mass, but would not be matter.[7] So the mass-energy of the entire universe including gravity adds up to exactly zero, giving rise to the cute idea that everything is just a quantum fluctuation, of the sort that happen from time to time. The Big Bang was a really big one.SBHarris 23:40, 3 June 2013 (UTC)

Clyde Greene (talk) 20:10, 8 July 2013 (UTC)== Normal Image: a 3d array ==

Normal Image: a 3d array, references as spheres defined by the charge / mass density . . the nucleus, the object projected and the electron shells being the image formed by the projection?

(1) Within the nucleous provides reaction sites thats extends as a region of frequencies [ie wavelengthes] give form or exist as nuclear particles. (2) Reflected Image: an array of electron configurations; references reaction sites [molecular form] formations of chemical bonds, etc. Note: Principle chemical analysis of matter defined by [radiation\absorption] over range of frequencies identify elemental orbitals while other wavelengths give bonds identifying electron configurations forming compounds, etc.

'Ah, . . early conceptions' of the atom! Yes, we agree that is matterrather losely defined concept just as element is a rather losely defined term. Classical concept of matter (form) mass and motion (energy) being represented as atoms. These particles of matter are then composed of subparticles; Having a spatical arrangement (reference) to charge. The (neutral) mass, neutron => positively charged particles (proton) and a negative particles (electron). Elements refer to the number and configuration of matter; each element has unique number of charged particles. These charged particles form specific confiurations within individual atoms of elements, but only those elements which form noble elements exist as indiviual (stable) atoms. The other elements/compounds form molecules (multiple nucli) attached or bonded via the outer negatively charged particles (electrons).

gas or smoke resembling gas

Shall we use smoke to resemble gas because it looks nicely with the other images with a black background when we have a good image of one of the few colored gases that can be seen well? Darsie42 (talk) 16:51, 14 November 2013 (UTC)

Lead sentence: MOS compliance

Starting a discussion thread following an apparent disagreement with Headbomb ...

At this time the article starts out as follows:

Matter is a poorly defined term in science (see definitions below). The term has often been used in reference to a substance (often a particle) that has rest mass. Matter is also used loosely as a general term for the substance that makes up all observable physical objects.

This violates MOS on two levels. First, the lead sentence does not provide a definition; rather it provides a disclaimer. This is a violation of WP:Lead. In general the first paragraph as a whole only vaguely defines the topic. Second, and more importantly, though, the lead violates WP:NAD. Whether or not the term matter has more than one definition is mostly beside the point (it is only really significant to the extent that one should make sure it is an appropriate title for the article). The lead should be defining the topic of the article, not the words in the title of the article. The fact that the words may have other definitions is a different issue (it may deserve a passing mention for clarity at the end of the article's lead but certainly should not be at the beginning of the lead).

The article is currently covering a broad range of overlapping sub-topics. It may perhaps be worthwhile to break these into more than one article (I don't have a strong opinion about that at this time). Nevertheless, whatever is the final result the articles need to following WP:Lead and WP:NAD.

The revised lead version I had suggested was

Matter is any substance that composes physical objects in the universe. The two most basic properties of matter are the mass that it possesses and the volume that it occupies. It is contrasted with energy, which acts on matter.

Whether or not this version is used, the MOS issues need to be fixed.

-- MC— Preceding unsigned comment added by 66.69.252.138 (talk)

References

The idea of defining matter as the stuff that makes up any Penrose "physical object" ("physical body" in your piped link MOS:PIPE) is droll, since if you go to the article on physical bodies it says they are identifiable collections of matter, all stuck together. How are we helped by such circularity? SBHarris 04:38, 27 August 2014 (UTC)

The distinction you make between matter and energy is incorrect. Kinetic energy, for example, does not "act on matter", rather it is an attribute of a physical object. In a more fundamental sense, mass and energy are the same, so if matter has mass it must also have energy. Gandalf61 (talk) 04:32, 1 December 2013 (UTC)

=

Been reading you with great interest, from old discussion to this. My own view lends to using the Pauli exclusion principle for defining matter. Doesn't matter if there are other 'forces' involved, 'virtual' or not'. Just as a electron becomes a 'electron cloud' in the modern definition, instead of singular particle uniquely defined to a momentum and position at each instant. But whatever ordinary matter is it takes a unique space to us humans, touch-ably so. So Pauli's definition suits me just fine, as for using 'energy' to define matter? Anyone that can give me a kg pure 'energy' here? Don't think so :)

Also, you might rethink "The reason for this is that in this definition, electromagnetic radiation (such as light) as well as the energy of electromagnetic fields contributes to the mass of systems, and therefore appears to add matter to them. For example, light radiation (or thermal radiation) trapped inside a box would contribute to the mass of the box, as would any kind of energy inside the box, including the kinetic energy of particles held by the box."

It (heat for example) adds mass to a material, but not 'matter' per se. Don't see them as the exact same myself? And would not formulate it as it now got 'touchable matter' added. Heat something and it will have the same constituents as when unheated, but will add vibrational behavior of those constituents inside that materials confinement (their kinetic energy). that 'energy' is temporarily held inside the material, adding a mass, until the materials constituents kinetic energy 'cools down'. All as I see it then.

As far as I know there is no experiment existing in where we by forcing a lot of EM 'energy' in a confined state can create a stable particle, as making a stick. What we have is a theory, or theory's, discussing regimes in where it should be possible, but unless proven as a experimental fact I would avoid defining 'energy' as equivalent particles (of rest mass). Furthermore this is a discussion about touchable matter right? Then let's stay with that, and leave 'pure energy' to theory.

77.218.18.208 (talk) 14:49, 26 August 2014 (UTC) Yoron.

A lot of EM energy makes "matter" all the time. If you shoot photons of more than 10 MeV or so through matter, you get a lot of pair production of electrons and positrons from the gammas. Those are matter particles and they are made directly out of gamma EM radiation. Matter (all kinds of particles) is also routinely made from kinetic energy in accelerator experiments. Protons that have never existed before can be made in an accelerator, and they become "touchable" hydrogen as soon as they pick up an electron. Does it make a difference to you that "touchable matter" can be made from various pure energies? And be converted back to them?

MC, it seems to me that this article is in no danger of violating WP:NAD until it focuses on the word "matter" more than the concepts behind it. It is in no danger of doing that. Wikipedia contains very many articles on topics which have a great many concepts subsumed into a single word, like religion,philosophy and alternative medicine, and none of them are in danger of violating WP:NAD either. But a lot of varying definitions are certainly given. SBHarris 04:35, 27 August 2014 (UTC)

Pentaquarks "not generally accepted"

This sentence is rather dated now that we have a peer-reviewed observation of two pentaquark resonances to high significance. Here is the journal paper: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.072001 --193.252.198.59 (talk) 18:25, 12 August 2015 (UTC)

matter

What is flam? It is a matter or energy? Ankit468 (talk) 22:37, 25 March 2016 (UTC)

Good question, but here we must discuss the article, not aspects of the subject, or of other subjects—see wp:talk page guidelines. For general questions, you can go to the wp:Reference desk/science. Good luck. - DVdm (talk) 22:56, 25 March 2016 (UTC)

Shoddy lead summary paragraph

Photons are, in fact, matter waves. They are both particles and waves, that like electrons, you can collide with (bump into). Thus the whole second paragraph should be either revamped or go imho. --Modocc (talk) 17:46, 12 October 2016 (UTC)

It isn't completely clear to me whether all matter waves (such as photons) must themselves be considered to be matter (or a type of matter)... But I do think the beginning of the lead should emphasize that matter *still* includes ordinary matter (not just pre-20th century) and that "ordinary matter" is a better-defined term than "matter" DavRosen (talk) 18:08, 12 October 2016 (UTC)

If you two are going to start modifying the lead, I suggest you first look at Matter#Definition. There is plenty of well-sourced discussion of various notions of what constitutes matter. Not including photons is consistent with the idea of antimatter - an electron has an antielectron, but there is no antiphoton. RockMagnetist(talk) 18:27, 12 October 2016 (UTC)

Of course, an antimatter matter collision can result in a photon cloud. The cloud of photons still fits the common definition given of mass occupying space. So its not clear why they should be excluded. --Modocc (talk) 20:29, 12 October 2016 (UTC)

(ec)Ofcourse there is an antiphoton it is called... a photon. (Note this could also be the for neutrinos, which could be Majorana fermions and therefore their own anti-particle.)TR 20:33, 12 October 2016 (UTC)

I see that the Oxford dictionary (which is reliable enough I suppose) stipulates matter has rest mass which each photon, in isolation, does not have, so I'll let this matter rest. To further my point however, one can arbitrarily remove any portion of a cloud's photons and those subcloud rest masses, just like with other composite objects that have mass-energy. The cloud's matter can be stripped one photon at at time from all its subclouds so nothing is left. This illustrates why the definition of matter should be that of objects with mass-energy that occupy space, but then many physicists that want to rid themselves of relativistic mass might balk, especially since there are different equations involved (yes I'm aware of them too, i.e. Maxwell's and the Schrödinger equation) regarding propagation. On the whole however, the exclusion of the multitude of fundamental force carriers that light our day and that one day may propel starships from the definition of matter just doesn't cut it for me, but it apparently does for those that should know better. --Modocc (talk) 00:05, 13 October 2016 (UTC)

The problem is that `matter' is not a fundamental concept in any modern theory of physics. Consequently, there really there is no real proper definition, and the word just gets thrown around with different meanings depending on context. To a relativist, `matter' would simply be anything that contributes to the right hand side of the Einstein equation. To a cosmologist, the `matter' component of the universe is stuff that moves non-relativistically (i.e. whose temperature is small compared to its rest mass). Then again, to a standard model field theorist, `matter' fields are simply the non-gauge fermionic fields. I think this page is currently too focused on definitions of matter. It probably would be a lot better if it simply focussed on the history of the subject, explaining the ambiguities that arise in modern physics.TR 08:01, 13 October 2016 (UTC)

sub to Jack The Hunter on YT.Sub to insidepingu on YT. The first sentence should link to the article on substance theory, as the word "substance" is used to define/explain the concept of matter

The word "substance" is not a word that can be left on its own as almost no one, let alone the layman, has an idea as to what it may mean and it's ambiguous anyway.

Since it is a key word in defining or explaining the concept of matter, it should be joined with a link to the article on substance theory.

Notice that when searching Wikipedia for "substance" you are referred, apart from the article on substance theory, to two others- one about chemical substances (a concept clearly less basic than matter), and the other to the article on matter itself. This strengthens my claim for the need of linking to substance theory, as people might think "substance" is just a synonym of matter, and thus the first sentence can be interpreted as using the concept of matter to define or explain matter. 132.72.130.205 (talk) 12:05, 21 November 2016 (UTC)

I added a link in Matter#See also. RockMagnetist(talk) 00:13, 22 November 2016 (UTC)

Cognitive dissonance

I'm a little concerned that the article is being pulled in two directions to accommodate two separate ideas of "matter", at least as far as I understand it. In particular, I think there's an unnecessary contention between the idea of matter in general and the notion of ordinary matter. I would like to see these two concepts separated into two separate articles, referencing each other, of course.

Of particular concern to me is the misleading statements about volume. My understanding is that volume is a property of ordinary matter, but not matter in general. In particular, volume loses meaning within the context of degenerate matter.

I would think that with some careful hatnotes and such, a reasonable balance could be found between these two ideas, eliminating some of the confusing dissonance that this article fosters by mixing the two notions. 47.32.217.164 (talk) 18:02, 18 May 2017 (UTC)

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What not protect?

Jovito11 (talk) 23:46, 21 March 2018 (UTC)

"volume" different from "space taken up" to the exclusion of other matter?

E.g. a gas "takes up" far less space than its volume because most of the volume is empty (we could put other atoms there). Only the fermions themselves take up space exclusively due to pauli? — Preceding unsigned comment added by DavRosen (talk • contribs) 23:34, 5 September 2017 (UTC)

@DavRosen: Are you talking about a specific part of the article? RockMagnetist(talk) 00:16, 22 March 2018 (UTC)

Matter

As we look at our sroundings we see a large variety of of things diffrent shapes, sizes,and textures. Everything in this universe is made up of material which scientist have named matter.😶😶 Shagun sindhia (talk) 14:11, 8 April 2019 (UTC)

Nyc Shagun sindhia (talk) 14:12, 8 April 2019 (UTC)

Edit request

I have checked the articles antimatter and quantum chemistry, and I haven't managed to spot any connection between the two subjects in either article. Apparently, antimatter isn't a major topic covered in quantum chemistry. Given this, I think the mention of "quantum chemistry" in the start of the Antimatter section of this article should be removed. --186.185.87.21 (talk) 03:54, 9 May 2019 (UTC)

I'm still waiting for an answer, guys. --186.185.60.147 (talk) 17:49, 7 June 2019 (UTC)

 Done: couldn't find any significant literature link either. I have removed the unneeded "in ..." part altogether: [8]. - DVdm (talk) 18:29, 7 June 2019 (UTC)

Matter vs Substance

In this article, the definition of matter is the following:

In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume.

Looking up for Substance, we see:

Substance may refer to:

• Substance (Jainism), a term in Jain Ontology to denote the base or owner of attributes
• Chemical substance, a material with a definite chemical composition
• Importance or depth
• Matter, anything that has mass and takes up space
• Substance theory, an ontological theory positing that a substance is distinct from its properties

If the right neaning is Matter, then it is a circular definition (vicious circle). If the right meaning is Chemical substance, the wikilink should point to that article.Ufim (talk) 14:53, 28 July 2019 (UTC)

True enough. Defining fundamental concepts in physics using natural language is often problematic. I would suggest a rephrase:

In physics and chemistry, matter is anything that has mass.

"Classical" physics and "general" chemistry is superfluous; debatably, fundamental massive particles have zero volume; and I agree that "substance" is, at best, unclear.

"anything" is also circular since a "thing" may be matter.

Thoughts? Cosmogoblin (talk) 18:28, 21 September 2019 (UTC)

I would just remove the naming of any science in that part. Matter is something that, well, matters for many other fields, not just physics or chemistry. And in all sciences, it has the same definition, so I don't feel like it's necessary to imply that the definition provided in the article is only true for one or two fields. --2601:701:300:4BC0:B061:6B20:C46:6CCD (talk) 18:55, 25 October 2019 (UTC)