This is an archive of past discussions about Matter. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.
"Colloquially and in chemistry, matter is easy to define. Matter is the stuff which things are made of and consists of chemical substances. These are made of atoms, which are made of protons, neutrons and electrons. In this way, matter is contrasted with energy."
Is it wise to use "Stuff" in the definition. The way I was taught "stuff" is slang and should be used in defining words if anyone can think of a better word please do so, it kinda looks out of place
Matter:Anything that has mass and takes up space
Mass:the amount of matter
Weight:the pull of gravity
Property Solid Liquid Gas
Has Weight Yes Yes Yes
Takes up Space Yes Yes Yes
Has its own definite shape Yes No No
Take the shape of the Container No Yes Yes
States Particles
Solid Move very slowly
Very close to each other
Liquid Move faster than Solid
Further apart
Gas Move very fast
Very apart from each other
The general properties of matter result from its relationship with mass and space. Because of its mass, all matter has inertia (the mass being the measure of its inertia) and weight, if it is in a gravitational field (see gravitation). Because it occupies space, all matter has volume and impenetrability, since two objects cannot occupy the same space simultaneously.
The special properties of matter, on the other hand, depend on internal structure and thus differ from one form of matter, i.e., one substance, to another. Such properties include ductility, elasticity, hardness, malleability, porosity (ability to permit another substance to flow through it), and tenacity (resistance to being pulled apart).
Matter is ordinarily observed in three different states, or phases (see states of matter), although scientists distinguish three additional states. Matter in the solid state has both a definite volume and a definite shape; matter in the liquid state has a definite volume but no definite shape, assuming the shape of whatever container it is placed in; matter in the gaseous state has neither a definite volume nor a definite shape and expands to fill any container. The properties of a plasma, or extremely hot, ionized gas, are sufficiently different from those of a gas at ordinary temperatures for scientists to consider them to be the fourth state of matter. So too are the properties of the Bose-Einstein and fermium condensates, which exist only at temperatures approximating absolute zero (−273.15°C), and they are considered the fifth and sixth states of matter respectively.
I'm very keen to have an accurate and precise definition of "matter" and "mass" for physics.
The article on Matter uses the term "substance" which is poorly defined as far as its use for Matter is concerned.
Suggestions?
One question: I understand and accept that matter occupies space, whatever that is, but does matter by definition or experiment have to exhibit mass as suggested in this article?
Well, matter isn't really accurately defined in physics, since it is somewhat arbitrary. If you want a precise definition the way SI units have precise definitions (except the kilogram which is lame and is defined by some chunk of metal), you're out of luck, because basically scientists generally consider certain particles matter but not others, and there isn't a good scientific reason for it. For example, W and Z bosons generally aren't considered matter, although they have huge masses.Eebster the Great (talk) 19:23, 17 March 2008 (UTC)
Matter and Energy
"...MATTER AND ENERGY WERE FUNDAMENTALLY SEPARATE TYPES OF MATERIAL."
EINSTEIN "SHOWED THAT MASS AND ENERGY WERE INTERCHANGABLE."
THERE IS AN IMPLICATION THAT MATTER AND MASS ARE THE SAME. THIS IS CONFUSING AND NEEDS CORRECTING AND EXPLAINING.
This sentence "Matter can more accurately be defined as the energy that has a low vibratory rate, a compressed energy state." is very confusing. Matter is made of protons, neutrons and electrons and these all have very HIGH vibratory rates (Compton frequencies of approx 10^20 to 10^23 Hz). Why does it state "LOW" vibratory rate? It would be more accurate to state that matter is energy travelling at velocity less than c.
This article needs a lot of cleaning up! Dpr 22:12, 5 Mar 2005 (UTC)
I gotta agree with Dpr. "(among which the photon)"... what?
In fact 'Matter' in physics is no longer defined. Even its SI system prototype is being abondoned. Any scientific definition we put here would in some way be considered original research. However, said that, we have to decide whether to define matter as a 'loosely defined' term, or put the next best thing we can think of, if we agree. Note that Einstein showed matter and energy are equivalent, but he never said they are the same thing. In physics we study the structure of matter, the structure of the nucleus, the structure of electron shells, etc.. In my opinion, matter should be simply defined as a 'structure of energy'. Whether one believes such structure is 2D (like De Broglie waves), 3D, 4D,.. or whether it has a knot form or a spherical standing wave structure is open to discussion, but we know for sure that matter is defined by its energy field structure and its energy level. - Blaze Labs Research14:44, 29 January 2007 (UTC)
"Structure of energy" is good. It is basically saying that the old-time philosophical concept of of "matter" amounts to that part of energy which has a natural rest frame (otherwise you can't catch it to look at its structure, or weigh it). So this essentially defines "matter" as any type of energy which isn't moving at c. Which is to say, that energy which has invariant mass. A proposal I put down someplace else, but which wasn't picked up. But it works better than the fermionic definition, subsuming kinetic energy and virtual particle mass, without also trying to take up classical EM radiation, and gravitational radiation, which we all agree doesn't fit will with the classical ideas of matter. So, I like it better.
But realize that we're on our own, here. Nobody else is really trying very hard to reconcile the old ideas in philosophy here, with the new realities of physics. SBHarris18:06, 29 January 2007 (UTC)
I would stay away from any 'invariant' term as my own research and of many other scientists does show that the 'mass' property of matter is not as invariant as most of us think. According to Mach's principle it could well depend on the relative position and energies of other 'structures of energy' within the universe. In other words, one cannot isolate one particle from the rest of the universe, because it's part of it, and since the universe is dynamic, so is the mass property of any matter. I've been doing research on this subject for the past 10 years, and can say that scientists have different ideas on this subject, but the majority do agree with the broad definition 'structure of energy'. So, I suggest we give some time to see if any opposition comes up to such as statement in here, and later move this definition to the article page. - Blaze Labs Research20:07, 30 January 2007 (UTC)
What is Matter
If you take a look at physics, matter is all that is studied by physics. But are photons matter? I am not sure. Photons are: massless, (gauge) bosons. Gravitons and gluons are also massless, but gluons are definately matter. The W and Z gauge bosons are massive, are they thus matter?MarSch 14:40, 18 Mar 2005 (UTC)
it seams that matter fields in QFT (Quantum Field Theory) are all fermion fields and that the bosonic interaction fields are not matter even though they may have mass. Thus weak vector bosons, which acquire mass through Higgs, would not be considered matter. MarSch 12:23, 6 Apr 2005 (UTC)
>> Matter, in the sense of content, is also used in contrast to form.
I love this sentence! It is cryptic, yet at the same time, concise and exact. -c neg
I agree that matter in physics is not easy to define. Nevertheless, I think mass is no longer fundamental for it, especially since modern physics does not postulate mass as an essential characteristic of particles anymore (only as a consequence of some interactions). Does matter appear only after symmetry breakdown through the Higgs mechanism? I think, matter is more general than that, in the same way I think electrons (leptons and fermions) are matter, too. They have much character of wave, but protons, too. Actually, atoms can be seen equally. And neutrinos (fermions), in the Standard Model they do not possess mass. They are fermions (leptons, such as electrons are) and within modern physics, all that is surely matter (or antimatter). Maybe bosons are not matter, bu then are Bose-Einstein condensates not matter? There are atoms which are bosons! What are they, then?
Surely, what physics say does not have to be a law, but the frontier between matter and "not-matter" is surely not easy to propose. Maybe, matter should be something as "everything that react to some interactions" (that for the beginning!!)
Without mass, neither electrons nor any other particle would act much like what we call "matter." So if you're going to be real technical, I would say that without the Higgs mechanism (assuming, of course, that it is what causes fermion masses) there would be no matter.
Also, nobody claimed bosons in general aren't matter. As you say, half of all nuclei are bosons, including many of the good ones like common isotopes of carbon and oxygen. What's been claimed is that fundamental bosons aren't matter, because they're force carriers. All this really amounts to is claiming that particles that can't be observed in any way in normal life aren't matter, and neither are photons, which seems fairly reasonable to me.
Maybe what we should really claim is that particles which can be bound permenantly in such a way as to have bulk properties constitute matter...? I'm pretty sure that won't work right either--you're right that this is hard. But it's better to start with one of the definitions I've mentioned than "everything that reacts to some interactions"--because that includes everything that it's possible to investigate scientifically. -- SCZenz18:36, 30 September 2005 (UTC)
We have another problem, and that is that most of the mass of "matter" is now known to be the gluons and kinetic energy of quarks, in the nucleons. The rest mass of quarks and leptons in ordinary objects are 1% haven't defined as "matter," in this article. So as it stands, we're really suggesting that most of the weight of a lump of ordinary matter, isn't "matter." That's really unsatisfying. We can live with the idea that a small fraction of the mass of "matter" is energy (force bosons, and not fermions. But almost ALL of it? We need a definition of "matter" which makes *most* of a lump of matter, MATTER. Not "energy."
Maybe we should quit trying to differentiate these particles, and just define matter as invariant mass, and be done with it. We generally do accept the idea of quantitating matter by means of weight and inertia, just as we do with invariant mass, do we not? SBH[[User: materia, which refers both to fermions and bosons, as generally accepted in modern Russian language. Interwiki from here points to another Russian word ru:Вещество, literally meaning what the things consist, used to denote only fermionic part of materia, as well as a chemical substance. In philosophy there are no difference between Russian materia and Western variants of this word. But it would be incorrect to translate the word matter in a physical article to Russian: Материя in most cases. гык20:27, 2 November 2006 (UTC)
Matter in role playing
Doesn't this addition seem a little bit too far-fetched for this article? Karol 09:01, July 31, 2005 (UTC)
Non necessarily, tho' it wasn't put in the right way. The article is "Matter", not "Matter (physics)", and "Matter (disambiguation)" does not exist. Many Wikipedia articles on words with many meanings but one of them very minor have at least a note explaining that another possible meaning exists.--Army198719:41, 15 August 2005 (UTC)
Yes, but a fictional version of matter that exists (as one of nine spheres of magic) in a particular roleplaying game? How many different articles are you going to add little notes to, to cover all the spheres of influence? Doesn't there have to be a limit somewhere? It's not reasonable to write an article about what matter actually is without calling it Matter (physics)?? -- SCZenz04:49, 16 August 2005 (UTC)
Yeah, but many minor meanings of words which don't deserve an article themselves have a Template:dablink note in the article for the main meaning of the word. For example, nobody would expect to find stuff about the program Eye Drops in the article for eye drop (singular and lowercase d, but nevertheless the latter has a dablink template note too.--Army198709:15, 16 August 2005 (UTC)
However, I may agree that this is not the place for details. They should be moved to the article for the game, however, since I've never played it, I'll simply delete the details here and add a stub note to the article for the game, leaving others to expand it.--Army198709:28, 16 August 2005 (UTC)
expert-expansion-sources
this article needs to be: more detailed (and hey, an image or two there is a lot of matter out there), more sourced (you know, like ANY), and an expert needs to go through and articulate the nitty-gritty. this is an article on MATTER in an ENCYCLOPEDIA. it's the least we can do. (wow, i sound kind of bitter posting this). JoeSmackTalk15:52, 13 September 2006 (UTC)
(Before I say this I want to be clear that it's not sarcastic, nor do I mean to discount the other things you mentioned.) What pictures would you choose to represent matter, given that a picture of absolutely anything would qualify? --Strait18:30, 13 September 2006 (UTC)
Actually, a representation of three-dimensional space (length, width, depth) in the form of a cube with a drawing or photo of the universe would go a long way towards helping to understand the definition of matter. Matter is discernable inside these three dimensions. Dark Matter is not. Therein lies the crux of the problem.Kchiles19:10, 4 March 2007 (UTC)
The trouble is, who's an expert? I'm not sure the way a physicist would define "matter" exactly fits common usage, and since it's such an imprecise and general word I'm not sure all physicists would agree anyway. -- SCZenz20:14, 13 September 2006 (UTC)
It's important to note that the definition of "Matter" is predicated on the unwritten understanding that our definition takes place inside of our three-dimensional world. Length, width, and depth define the limitations of matter in our world. Contrast this with "Dark Matter", which (I think we can agree on this point) operates outside the three dimensions that we perceive. It's important to note that we define matter within our three dimensions, in order to encourage exploration of ways to perceive items outside of "our" three dimensions. Once we can perceive items outside of these three dimensions, much more of the universe will be revealed to us.
The obvious experts in our journey will be mathematicians, who will be able to help us in our quest to understand and quantify dimensions beyond our three. Source: The Joy of Thinking: The Beauty and Power of Classical Mathematical Ideas (DVD Course by The Teaching Company) Taught by Michael Starbird & Edward B. Burger.Kchiles19:46, 4 March 2007 (UTC)
I understand why you added {sources} and {expert}, but I disagree about {expand}. Matter is a very general, vauge topic. All of the specifics should be covered in the pages about specific types of matter, I think. Can you name anything (besides images) that you'd like to see discussed here? --Strait23:59, 13 September 2006 (UTC)
By:
Brian Santos
== Lenin An Authority on Physics? == jajajajajajajajajandm
I'm confused about the prominent quote by Lenin in the first paragraph of this article. He was a politician, not a physicist. What reason is there to use his working definition of matter? Why not a quote from John Dalton or Mendeleev or someone else with actual scientific credentials? --Robigus04:50, 9 November 2006 (UTC)
This is one guy, posting from freenet.de in Germany. All the posts are from anon IP's which are of the form 89.50.y.xx, with y being 8,0,or 1. Examples from the last month, all adding the Lenin crap and going back to a long past article version, are:
89.50.8.59
89.50.8.92
89.50.8.62
89.50.0.164
89.50.1.32
89.50.8.38
89.50.8.92
89.50.8.62
89.50.0.164
89.50.1.32
89.50.8.38 This one twice...
This goes all the way back to the first Lenin quote addition of the LEAD, which was relatively pure, on Oct 16, by this same guy using the same anon 89.50.x.xx IP. By now, it's caught up with a lot of article previous versions, and conflicts with a lot of stuff later added by others. If you see IP anon additions to this article, beginning with IP 89.50...., just revert them. If I could write a bot to do this, I would. SBHarris16:57, 15 January 2007 (UTC)
E=mc2
E=mc2 does not exactly "say they are the same thing". Let F be the number of finges you have, and T be the number of toes yu have. Then F=t (in all likelihood), but fingers are not the same thing as toes. The mathematical language of phsyics underdetermines metaphysics, that is why there are umpteen interpretations of QM.
however, interconvertability is hard to dispute isnce it is the basis of technologies such a nuclear energy.
In the case of E=mc^2, it really does mean they are the same thing. It isn't just that one can be "converted" to the other. Rather, one never APPEARS without the other. E and M are two different names for the same stuff, like rain and snow. In the case of rain and snow, you never have either of them, without having H20 already. All forms of energy which are definable by multiple observers (ie. are objectively real, and don't depend arbitrarily on the reference frame chosen) HAVE an invariant mass. They aren't "converted" from mass. Mass is a property they always have, and never lose. My problem is that the way the article is writen now is misleading, and could be fixed with a little attention, and not all that much addition. But right now, it's subtly wrong. The real problem with differentiating energy from "matter" is that energy HAS mass, so it's already matter by the most important criterion for matter. All objective energy (not dependent on observer) can be weighed, has a gravitational field, inertia, and so on and so on. That's a much stronger statement than the idea that it could "turned into" mass if we wanted to. It already IS mass. See the point? SBHarris00:07, 25 March 2007 (UTC)
You are using "matter" and "mass" interchangeably. However, by the fermion definition, energy and matter are still two different things because bosons and fermions are different.1Z16:10, 27 March 2007 (UTC)
Yes, but as pointed out in the article, the fermion definition isn't very useful, because colloqially, "matter" is expected to make up most, if not all, of things with mass, and it doesn't if you define matter as fermions. Most of ordinary objects are not composed of the mass of fermions. When you pick up an ordinary object, 99% of what you pick up and heft isn't fermions, but rather their kinetic energy and bosons like gluons. All of which would be non-matter, by that definition. It's either somewhat counterintuitive or else counter-usage, that 99 lbs of a 100 lb sack of potatoes is non-matter. Yet that's what you're stuck with, in the fermion definition. SBHarris07:43, 22 April 2007 (UTC)
Few people think mass is mostly non-matter. Most colloquial users of the word "matter" would object to the idea that most of the weight of ordinary objects is NOT "matter", i.e., that "matter" should be regarded as only a tiny fraction (<1%) of "what takes up space and has mass" in ordinary life. SBHarris05:08, 11 January 2008 (UTC)
In Stanford Encyclopedia of Philosophy there is an article on E=mc^2 discussing two different interpretations of the formula. RickardV11:27, 15 April 2007 (UTC)
Reversion
I have reverted Enormosududes recent changes to the article. Some of his claims are doubtful. The Pauli exclusion principle is not the cause of the rigidity of normal matter - it only becomes important in degenerate matter states, such a neutron stars. Visible matter include dust clouds as well as stars. Most scientists, I think, would not include gauge bosons such as photons and gravitions within their definition of matter. Their are also several grammatical errors in his contributions - "same refers", "dark matter seem". As it seemed too difficult to improve his contributions, I decided to revert them. Gandalf6121:32, 4 April 2007 (UTC)
The up quark mass
Is 1.5 to 3 mev: [1]. Somebody keeps reverting this to an old version of the article which never did get this right, and says is "may" be massless. The reference (now outdated) never did say what the bad version says it did. The correct reference is above. Check it out. SBHarris02:32, 11 October 2007 (UTC)
Definition
"Since protons, neutrons and electrons combine to form atoms, molecules and the bulk substances which they make up with all matter." This sentence makes no apparent sense. Unfortunately I cannot figure out what it is supposed to mean. Can anyone remedy this? `Alcmaeonid (talk) 22:03, 30 January 2008 (UTC)
Merged text from Chemical matter page
I merged text from the Chemical matter page (it's now a redirect). I think that the resulting new section could be slimmed down considerably, or even eliminated; but I will defer to this page's editors to determine exactly how. Bry9000 (talk) 00:20, 1 February 2008 (UTC)
– The section uses new and inconsistent terminology , "chemical atoms" does not sound right. Perhaps some of the text should move to become a subgroup of homogeneous matter, which (rearranged) could be: elemental matter .. iron, mixture of elemental matter .. brass, or chemically bonded elemental matter "chemical matter" aka [chemical substance], for instance hydrogen (H2) or water (H2O) . The focus of the section is mainly on types of matter in the universe, the topic appears relevant to me, but it makes the heading misleading. Perhaps a new heading and a link to the new concept of "dark energy". Frank.hedlund (talk) 09:58, 7 February 2008 (UTC)
The only reason that disappoints you is because you assume matter is "condensed energy." However, that is not really what matter is, hence the reason it doesn't show up in the article. Suffice it to say that a well-defined, scientific analog to the common definition of matter could be fermions, but that there is no truly scientific definition right now. "Condensed" energy is a nonsensical term. Condensed in what way? Is the energy simply localized? What kind of energy? Surely dark energy is not matter no matter how small the scale you observe it. Photons are "condensed" in the sense that they occupy a single, infinitely dense point, but they are rarely if ever considered to be "matter." Eebster the Great (talk) 22:00, 5 October 2008 (UTC)
Editing Talk Pages
A long portion of one of my comments as well as short comments by users Dpr and 74.78.162.229 were removed without comment by editors Wwheaton and 24.139.29.52. I'm going to go ahead and guess 24.139.29.52 has no good reason, as he has made no comments nor even left his name, but I would be interested in seeing why Wwheaton deleted an unaddressed comment, even if he didn't like how it was stated. Comments from other users should not be edited or removed, but merely addressed. Eebster the Great (talk) 06:48, 4 October 2008 (UTC)
I am actually not quite clear what you are talking about, it may have been an accident. I will respond on your talk page, but apologize if I mangled your edit. Wwheaton (talk) 07:06, 6 October 2008 (UTC)
"Matter is any type of physical information that takes up space."
because I am not clear it is correct and also because I think it will be confusing to most non-specialist readers. Information is certainly deeply in physics, but the essential connection to matter seems less clear to me than mass and energy. Maybe I just need to have it explained & clarified? Anyhow, I'd appreciate some comment before it goes back into the main article. Thanks, Wwheaton (talk) 16:35, 6 October 2008 (UTC)
I'm gonna do a comprensive rewrite of this article soon.
There are so many problems with this article I don't really know where to being. I've already fix the big errors that mesons and that bosons in generals were not matter (as opposed to elementary bosons are not matter, but composite ones may be), and clarified the definitions in more exact terms. I'll try to give a bigger overview of the properties of matter, and try to give a "chemical definition of matter". Headbomb {ταλκ – WP Physics: PotW} 18:23, 6 October 2008 (UTC)
Well, you or somebody has managed to delete the main problem that needs discussion, which is that most of the mass or "ordinary matter" (a glass of water, say) is NOT fermions. It is NOT quarks and leptons. The 2 ups and 1 down quarks in protons have rest masses of about 4 and 7 MeV, respectively for a total quark rest mass of 15 MeV. The mass of the proton is 938 MeV. See for example: http://www.npl.washington.edu/AV/altvw80.html. Here's a quote:
On the other hand, the proton (size about 10-15 m) is much heavier than the combined masses of its three components (two up quarks and one down quark). The proton's mass in energy units is 938 MeV, while the up quark has a mass of only about 4 MeV and the down quark about 7 MeV. The majority of the proton's mass comes from the kinetic energy of its quark components. Within a proton the quarks are confined to a "box" only 10-15 m across. Heisenberg's uncertainty principle dictates that the product of uncertainties in position and momentum must be greater than h-bar, so a quark localized to 10-15 m must have a momentum uncertainty of at least 197 MeV in energy units. The energy contributions from three quarks having about this momentum in each of three space directions approximately equals the proton mass. The proton thus derives its net mass energy mainly from the internal motions of its constituent quarks, not from their rest masses.
Basically, most of the mass of ordinary matter is the kinetic energy of bound quarks, measured as part of the invariant mass in the proton's center of momentum, or rest frame. It is as though you had a superstrong box of very hot plasma-- so hot that the kinetic energy of the particles was far larger than the rest masses of the particles themselves when cold. That's a normal baryon. And thus, this is most of what composes the "mass" of normal matter. It's nothing but kinetic energy. SBHarris21:05, 6 October 2008 (UTC)
I would think that mass is something that needs to be discuss in the mass article rather than in the matter article. Same goes for the mass of the quarks vs mass of bunches of quarks. I would think that this would be better suited in the quarks article and in the higgs mechanism article. Headbomb {ταλκ – WP Physics: PotW} 22:19, 6 October 2008 (UTC)
Not if you persist in defining "matter" as "fermions." If you want to define matter as fermions, fine, but note then that most of the mass of ordinary matter, under that definition, is not matter! That is counterintuitive. When you lift a glass of water, most of what you heft is not fermions, but rather the kinetic energy of the fermions. Since mass is one of the two main properties we attribute to matter, we should note that most of one of these properties isn't due to any particles at all. It is indeed "condensed" or (better) trapped energy of motion. SBHarris22:27, 6 October 2008 (UTC)
Well I've put a section for the fundamental properties of matter. I suspect that mass would go in there, so you can write something for that section if you want. Headbomb {ταλκ – WP Physics: PotW} 00:02, 7 October 2008 (UTC)
I continue to believe that the Spin-statistics theorem and the Exclusion principle are an essential part of the concept of matter. Clearly all forms of energy contribute equally to inertia, and thus to mass, but the "solidity" of ordinary matter derives from the exclusion principle in the context of atomic physics (and also degenerate stars, for that matter), and that falls back to elementary fermions. Bosonic field quanta are clearly essentially different, in practice and in theory. I think this needs to be retained in some form. Wwheaton (talk) 02:39, 7 October 2008 (UTC)
It don't really see what Pauli has to do here, but I'm not opposed to including it if its relevant. I would also worry about brining overly technical stuff to an article that is already technical enough (blame me for that). It's already mentionned that matter = stuff made of elementary fermions, and that elementary bosons have nothing to do with matter (other than carrying forces).Headbomb {ταλκ – WP Physics: PotW} 02:55, 7 October 2008 (UTC)
I'm not even sure what the exclusion principle does, except to make matter less dense than it otherwise would be. But even if electrons were bosons, atoms would still have a sizable fraction of their present volume. All the electrons would simply be in the same 1s orbital. But that orbital would have a size, and that size would be increase a bit, as you added new electrons. What size? The same size the 1s orbital is now, in heavy atoms. That's not zero-- it's still quite large compared with the nucleus-- something like 0.1 Angstrom. Matter might have, at a guess, 1000 times present density. And would be chemically very boring as all elements would be inert and appear nearly the same. But structure, mass, density, resistance, volume, and all that other stuff would still remain. Consider helium-4, which is made of bosons. Even in a superfluid condensate state, it still has volume and density. These things don't just go away because you have a bunch of particle in the same quantum stante. They only go away if the particles themselves have no charge, no mass, and no volume (like photons).SBHarris07:42, 7 October 2008 (UTC)
This definition is also problematic inasmuch as most of the mass which is present in ordinary matter is not the intrinsic mass of the fermions which make it up. The up and down quarks which make up ordinary matter have only about 2% of the mass of the baryons which they compose. This means that about 98% of the mass of ordinary matter is due to the kinetic energy of confined quarks and their binding energy, which is due to gluons which have no rest mass themselves: the kinetic energy of particles on a confined system contributes to the invariant mass to the system (see mass in special relativity). [1]
I've deleted it because I think this is very misleading. I really don't see what problem mass causes to quark-lepton definition of matter. This really seems to be something more appropriate for the mass article than the matter article (and even then, it wouldn't be a problem).Headbomb {ταλκ – WP Physics: PotW} 07:31, 14 October 2008 (UTC)
Well, if I define matter as "elementary fermions", less than 1% of my mass is mass of matter is not something I can hear while staying terribly confident that the definition is decent. OTOH, if I define matter as "anything with nonzero invariant mass", then the fact than a single photon is not matter whereas the system composed of two photons with non-parallel momenta is troubles me no more than the fact than single slices of bread or of ham aren't sandwiches but the system composed by two slices of bread with one or more slice of ham between them is one. But WP is not a soapbox, and I've got better things to do than trying to translate this into something encyclopedic and looking for a reference making this point, so I'm not going to re-add that paragraph. --Army1987 (t — c)19:01, 17 October 2008 (UTC)
Look, I understand that it'll be puzzling to all that a proton, made of three quarks whose individual masses sum up to about 12 MeV/c2, has a mass of 938 MeV/c2. But that you can't straightforwardly add the masses of quarks to get the masses of the composite particles (mesons, baryons) isn't a result of defining matter in terms of whether or not they are elementary fermions, nor does it cause a problem in terms of a nested hierarchy classification. You have matter (quarks and leptons), and you have force-carriers (gauge bosons).
If you define matter in terms of mass however, then you have a problem, because you have families of particles that are composed of matter and non-matter (under this definition). This is very ugly and breaks the nested hierarchy. Photon would then be the only thing that isn't matter (and the graviton as well if it exists). Such a definition is pretty near useless. Hence the quarks and leptons definition. Headbomb {ταλκ – WP Physics: PotW} 21:30, 17 October 2008 (UTC)
"If you define matter in terms of mass however, then you have a problem..." Glad to hear you say it. Since the article, as writen, DOES define matter has that which has mass (and takes up space). Hence, the problem. The individual fermions in matter don't take up any space (they have no volume that we can detect). And they contribute less than 2% of the mass. So most of the mass and all of the volume in "matter" is not fermions, but is due to the interactions between fermions, and due to their kinetic energy. To call the fermions the "matter" in matter, when you're defining matter in terms of mass and volume, is like defining a "plasma" as simply the particles that make it up, without saying anything else about them. Imagine a plasma so hot that most of its mass is from the heat itself. You're going to define it as the particles and not mention the heat at all? SBHarris04:17, 18 October 2008 (UTC)
Classically, the definiens of a definition consisted of a genus (a larger collection of things including the species (set of things to be defined)) and differentia (a property possessed by members of the species, but not by other members of the genus). What is the genus of matter? What is its differentia?
Are you trying to distinguish it: From empty space? From radiation? From force? From abstractions or ideas? From fictitious entities? Or what? JRSpriggs (talk) 04:48, 18 October 2008 (UTC)
"Since the article, as writen, DOES define matter has that which has mass (and takes up space). Hence, the problem. - SBHarris"
Yes, and in the "mass definition" section, the problem of a mass definition is explained. The problem is that it does not lead to a nested hierarchy and is thus an inelegant and near useless definition. That baryons and mesons masses not being the sum of the bare mass of their constituent quarks is another "problem", unrelated to the definition of what constitutes matter. Headbomb {ταλκ – WP Physics: PotW} 06:02, 18 October 2008 (UTC)
What is the genus of mathematical sets? The ZFC axioms (or whichever axioms you use) are the differentia, but what is the genus? What are the genus and differentia of feelings? What are the genus and differentia of evil? And what is this "nested hierarchy" problem? The fact which words can have partly overlapping scope is common in natural languages, and it has had no terrible consequence I'm aware of. Not all fruits are food and not all food is fruits; not all meat is food and not all food is meat; but no-one would say "the definition of food does not lead to a nested hierarchy and is thus an inelegant and near useless definition". OTOH, defining matter as "elementary fermions" has other problems: in annihilation and pair production matter pops in and out of existence; but if you define it as "anything with nonzero invariant mass", since the total invariant mass of a system is conserved unless the system is not closed, you would simply say that matter has entered or left the system. But anyway... This talk page is supposed to be for discussing improvements to the article, right? So, maybe I've already ranted too long... --Army1987 (t — c)10:18, 18 October 2008 (UTC)
No, that was a perfectly good rant. You're arguing with Objectivist-type people who think with Ayn Rand that all definitions should (must) be of the binomial nomenclature type (as per Linnaeus), but then can't deal with fuzzy borders or non-nested categories, and so want to tromp all over natural language in order to "fix" it. Examples of which you gave. It's hard to define "humor" or "irony," for example, when different people mean different things by it. Matter is the same way: it's not a scientific word so much as a cultural one which involves subjectity. We can't fix that on Wikipedia, except to give examples of the various definitions that various people have used over time. Trying to tack it down by equating it with some well defined science concept, is just wrong. It's like insisting that when we talk about the energy of a policial speech, or a violin performance, that we define it properly in joules. SBHarris03:56, 19 October 2008 (UTC)
Regardless of whether it's a perfectly good rant or not, strictly speaking it's out of place here, as this page is for discussing improvements to the article, so I did have to apologize for it. --Army1987 (t — c)08:56, 19 October 2008 (UTC)
Why do you insist on saying I define them as "anything with nonzero invariant mass"? I don't. Matter is composed of the elementary fermions. If it's composed of elementary fermions, then it's matter, if it's not composed of elementary fermions then it's not matter. End of story. Nothing to do with mass. Nothing to do with pair creation and annihilation. Headbomb {ταλκ – WP Physics: PotW} 15:35, 18 October 2008 (UTC)
I only meant that I don't like it; but that's just me, and the article is fine as it is. (I think that few people are so enthusiastic with Franklin's definition of vitreous electricity as "positive" and resinous electricity as "negative", which forces us to write absurdities such as Cl− to refer to something which is something more than a Cl atom, or that current in metals flows in the opposite direction of the drift velocity of electrons; and probably fewer people like the fact that the ampere is a fundamental unit and the coulomb is derived; but that's the way it is, and no-one is going to change that; so arguing about that is essentially a waste of time, like what I have been doing now.) --Army1987 (t — c)19:17, 18 October 2008 (UTC)
Don't give up so easily. Mass is a scientific word with a good scientific definition, but matter is not. There is no SI definition for "matter", which we might not like, but have to live with. Instead, there's just bunch of POV pushing by various editors, who have a bug up their behinds as to what THEY think "matter" should mean, instead of what people commonly mean, and what the dictionaries say. If you find me a Webster's dictionary (or even any scientific dictionary) which defines "'matter" as "anything made up of fermions", I'll eat the page. SBHarris03:59, 19 October 2008 (UTC)
The article already says that "physicists generally do not use the term matter when precision is needed", so what's the matter? (Sorry for the really bad pun.) --Army1987 (t — c)08:56, 19 October 2008 (UTC)
The problem is that the remaining text gives the lie to that statement, by defining "matter" as fermions, without stating what the problems of that definition are. If physicists really define matter as fermions, they would use the term when precission was needed. The precise definition would be (and this article now suggests that it is): "Any fermion, or collection of fermions, and nothing else." SBHarris20:39, 19 October 2008 (UTC)
This is an archive of past discussions about Matter. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.
I'm gonna do a comprensive rewrite of this article soon.
There are so many problems with this article I don't really know where to being. I've already fix the big errors that mesons and that bosons in generals were not matter (as opposed to elementary bosons are not matter, but composite ones may be), and clarified the definitions in more exact terms. I'll try to give a bigger overview of the properties of matter, and try to give a "chemical definition of matter". Headbomb {ταλκ – WP Physics: PotW} 18:23, 6 October 2008 (UTC)
Well, you or somebody has managed to delete the main problem that needs discussion, which is that most of the mass or "ordinary matter" (a glass of water, say) is NOT fermions. It is NOT quarks and leptons. The 2 ups and 1 down quarks in protons have rest masses of about 4 and 7 MeV, respectively for a total quark rest mass of 15 MeV. The mass of the proton is 938 MeV. See for example: http://www.npl.washington.edu/AV/altvw80.html. Here's a quote:
On the other hand, the proton (size about 10-15 m) is much heavier than the combined masses of its three components (two up quarks and one down quark). The proton's mass in energy units is 938 MeV, while the up quark has a mass of only about 4 MeV and the down quark about 7 MeV. The majority of the proton's mass comes from the kinetic energy of its quark components. Within a proton the quarks are confined to a "box" only 10-15 m across. Heisenberg's uncertainty principle dictates that the product of uncertainties in position and momentum must be greater than h-bar, so a quark localized to 10-15 m must have a momentum uncertainty of at least 197 MeV in energy units. The energy contributions from three quarks having about this momentum in each of three space directions approximately equals the proton mass. The proton thus derives its net mass energy mainly from the internal motions of its constituent quarks, not from their rest masses.
Basically, most of the mass of ordinary matter is the kinetic energy of bound quarks, measured as part of the invariant mass in the proton's center of momentum, or rest frame. It is as though you had a superstrong box of very hot plasma-- so hot that the kinetic energy of the particles was far larger than the rest masses of the particles themselves when cold. That's a normal baryon. And thus, this is most of what composes the "mass" of normal matter. It's nothing but kinetic energy. SBHarris21:05, 6 October 2008 (UTC)
I would think that mass is something that needs to be discuss in the mass article rather than in the matter article. Same goes for the mass of the quarks vs mass of bunches of quarks. I would think that this would be better suited in the quarks article and in the higgs mechanism article. Headbomb {ταλκ – WP Physics: PotW} 22:19, 6 October 2008 (UTC)
Not if you persist in defining "matter" as "fermions." If you want to define matter as fermions, fine, but note then that most of the mass of ordinary matter, under that definition, is not matter! That is counterintuitive. When you lift a glass of water, most of what you heft is not fermions, but rather the kinetic energy of the fermions. Since mass is one of the two main properties we attribute to matter, we should note that most of one of these properties isn't due to any particles at all. It is indeed "condensed" or (better) trapped energy of motion. SBHarris22:27, 6 October 2008 (UTC)
Well I've put a section for the fundamental properties of matter. I suspect that mass would go in there, so you can write something for that section if you want. Headbomb {ταλκ – WP Physics: PotW} 00:02, 7 October 2008 (UTC)
I continue to believe that the Spin-statistics theorem and the Exclusion principle are an essential part of the concept of matter. Clearly all forms of energy contribute equally to inertia, and thus to mass, but the "solidity" of ordinary matter derives from the exclusion principle in the context of atomic physics (and also degenerate stars, for that matter), and that falls back to elementary fermions. Bosonic field quanta are clearly essentially different, in practice and in theory. I think this needs to be retained in some form. Wwheaton (talk) 02:39, 7 October 2008 (UTC)
It don't really see what Pauli has to do here, but I'm not opposed to including it if its relevant. I would also worry about brining overly technical stuff to an article that is already technical enough (blame me for that). It's already mentionned that matter = stuff made of elementary fermions, and that elementary bosons have nothing to do with matter (other than carrying forces).Headbomb {ταλκ – WP Physics: PotW} 02:55, 7 October 2008 (UTC)
I'm not even sure what the exclusion principle does, except to make matter less dense than it otherwise would be. But even if electrons were bosons, atoms would still have a sizable fraction of their present volume. All the electrons would simply be in the same 1s orbital. But that orbital would have a size, and that size would be increase a bit, as you added new electrons. What size? The same size the 1s orbital is now, in heavy atoms. That's not zero-- it's still quite large compared with the nucleus-- something like 0.1 Angstrom. Matter might have, at a guess, 1000 times present density. And would be chemically very boring as all elements would be inert and appear nearly the same. But structure, mass, density, resistance, volume, and all that other stuff would still remain. Consider helium-4, which is made of bosons. Even in a superfluid condensate state, it still has volume and density. These things don't just go away because you have a bunch of particle in the same quantum stante. They only go away if the particles themselves have no charge, no mass, and no volume (like photons).SBHarris07:42, 7 October 2008 (UTC)
The reason I continue to believe the Exclusion principle (and thus the Spin-statistics theorem) is a central part of the concept is that the commonplace definition, roughly "matter has mass and occupies space" requires it, in order to support the second half of the conjunction. Matter not only has a spatial dimension and place, it also excludes other matter from its locale, and not merely via repulsive force-carriers like the photon. Although other, non-spatial, quantum numbers are involved, this absolute denial of occupancy of the same quantum state is what forces us to classify elementary fermions, and composites thereof, as "matter" (including, say 4He, a composite boson) and exclude from the definition the photon, the W, and the Z, even though the latter have rest mass. Of course a composite system may have internal energy, and that may dominate its mass, as it does for the nucleons and thus all ordinary matter. But without the exclusion property, it seems to me we have no grounds to distinguish mass from anything that has energy, such as glueballs, for example. If we did that, then we should just have an article for "Energy", and all "Matter" would fall under that heading.
Of course one might argue that the commonplace, "folk" definition should have no place in fundamental physics at all. But I think the fact that superfluid He does not collapse to the size of a single 4He atom may be a strong indication that does. Wwheaton (talk) 22:47, 2 December 2008 (UTC)
Alright that make senses. It's not a defining property, but it certainly follows from it. I didn't read the article for a while so I don't know if it's been added or not, but if it hasn't been included, then feel free to add it.Headbomb {ταλκκοντριβς – WP Physics} 05:03, 3 December 2008 (UTC)
Your suggested addition of a discussion of the exclusion principle probably is not related to the common use definition of "mass and occupying volume", which more probably stems from a long historical record going back in time well before the exclusion principle raised its head. You might find Pauli_exclusion_principle#Stability_of_matter helpful. Brews ohare (talk) 16:03, 3 December 2008 (UTC)
Thanks for your link to Pauli_exclusion_principle#Stability_of_matter, which I had missed previously, and do find helpful. However, it seems to me to confirm my point, which perhaps I expressed poorly. Of course the common understanding of matter occupying space (and being "impenetrable", as my ancient school text claimed) far predates any understanding of the exclusion principle, but I still think the exclusion principle is the root cause of that property, and necessitates the link to elementary fermions. I would not necessarily discuss it extensively in this article, but I think it deserves mention, maybe via the wikilink you so helpfully provide? — Bill Wwheaton (talk) 19:36, 3 December 2008 (UTC)
This definition is also problematic inasmuch as most of the mass which is present in ordinary matter is not the intrinsic mass of the fermions which make it up. The up and down quarks which make up ordinary matter have only about 2% of the mass of the baryons which they compose. This means that about 98% of the mass of ordinary matter is due to the kinetic energy of confined quarks and their binding energy, which is due to gluons which have no rest mass themselves: the kinetic energy of particles on a confined system contributes to the invariant mass to the system (see mass in special relativity). [2]
I've deleted it because I think this is very misleading. I really don't see what problem mass causes to quark-lepton definition of matter. This really seems to be something more appropriate for the mass article than the matter article (and even then, it wouldn't be a problem).Headbomb {ταλκ – WP Physics: PotW} 07:31, 14 October 2008 (UTC)
Well, if I define matter as "elementary fermions", less than 1% of my mass is mass of matter is not something I can hear while staying terribly confident that the definition is decent. OTOH, if I define matter as "anything with nonzero invariant mass", then the fact than a single photon is not matter whereas the system composed of two photons with non-parallel momenta is troubles me no more than the fact than single slices of bread or of ham aren't sandwiches but the system composed by two slices of bread with one or more slice of ham between them is one. But WP is not a soapbox, and I've got better things to do than trying to translate this into something encyclopedic and looking for a reference making this point, so I'm not going to re-add that paragraph. --Army1987 (t — c)19:01, 17 October 2008 (UTC)
Look, I understand that it'll be puzzling to all that a proton, made of three quarks whose individual masses sum up to about 12 MeV/c2, has a mass of 938 MeV/c2. But that you can't straightforwardly add the masses of quarks to get the masses of the composite particles (mesons, baryons) isn't a result of defining matter in terms of whether or not they are elementary fermions, nor does it cause a problem in terms of a nested hierarchy classification. You have matter (quarks and leptons), and you have force-carriers (gauge bosons).
If you define matter in terms of mass however, then you have a problem, because you have families of particles that are composed of matter and non-matter (under this definition). This is very ugly and breaks the nested hierarchy. Photon would then be the only thing that isn't matter (and the graviton as well if it exists). Such a definition is pretty near useless. Hence the quarks and leptons definition. Headbomb {ταλκ – WP Physics: PotW} 21:30, 17 October 2008 (UTC)
"If you define matter in terms of mass however, then you have a problem..." Glad to hear you say it. Since the article, as writen, DOES define matter has that which has mass (and takes up space). Hence, the problem. The individual fermions in matter don't take up any space (they have no volume that we can detect). And they contribute less than 2% of the mass. So most of the mass and all of the volume in "matter" is not fermions, but is due to the interactions between fermions, and due to their kinetic energy. To call the fermions the "matter" in matter, when you're defining matter in terms of mass and volume, is like defining a "plasma" as simply the particles that make it up, without saying anything else about them. Imagine a plasma so hot that most of its mass is from the heat itself. You're going to define it as the particles and not mention the heat at all? SBHarris04:17, 18 October 2008 (UTC)
Classically, the definiens of a definition consisted of a genus (a larger collection of things including the species (set of things to be defined)) and differentia (a property possessed by members of the species, but not by other members of the genus). What is the genus of matter? What is its differentia?
Are you trying to distinguish it: From empty space? From radiation? From force? From abstractions or ideas? From fictitious entities? Or what? JRSpriggs (talk) 04:48, 18 October 2008 (UTC)
"Since the article, as writen, DOES define matter has that which has mass (and takes up space). Hence, the problem. - SBHarris"
Yes, and in the "mass definition" section, the problem of a mass definition is explained. The problem is that it does not lead to a nested hierarchy and is thus an inelegant and near useless definition. That baryons and mesons masses not being the sum of the bare mass of their constituent quarks is another "problem", unrelated to the definition of what constitutes matter. Headbomb {ταλκ – WP Physics: PotW} 06:02, 18 October 2008 (UTC)
What is the genus of mathematical sets? The ZFC axioms (or whichever axioms you use) are the differentia, but what is the genus? What are the genus and differentia of feelings? What are the genus and differentia of evil? And what is this "nested hierarchy" problem? The fact which words can have partly overlapping scope is common in natural languages, and it has had no terrible consequence I'm aware of. Not all fruits are food and not all food is fruits; not all meat is food and not all food is meat; but no-one would say "the definition of food does not lead to a nested hierarchy and is thus an inelegant and near useless definition". OTOH, defining matter as "elementary fermions" has other problems: in annihilation and pair production matter pops in and out of existence; but if you define it as "anything with nonzero invariant mass", since the total invariant mass of a system is conserved unless the system is not closed, you would simply say that matter has entered or left the system. But anyway... This talk page is supposed to be for discussing improvements to the article, right? So, maybe I've already ranted too long... --Army1987 (t — c)10:18, 18 October 2008 (UTC)
No, that was a perfectly good rant. You're arguing with Objectivist-type people who think with Ayn Rand that all definitions should (must) be of the binomial nomenclature type (as per Linnaeus), but then can't deal with fuzzy borders or non-nested categories, and so want to tromp all over natural language in order to "fix" it. Examples of which you gave. It's hard to define "humor" or "irony," for example, when different people mean different things by it. Matter is the same way: it's not a scientific word so much as a cultural one which involves subjectity. We can't fix that on Wikipedia, except to give examples of the various definitions that various people have used over time. Trying to tack it down by equating it with some well defined science concept, is just wrong. It's like insisting that when we talk about the energy of a policial speech, or a violin performance, that we define it properly in joules. SBHarris03:56, 19 October 2008 (UTC)
Regardless of whether it's a perfectly good rant or not, strictly speaking it's out of place here, as this page is for discussing improvements to the article, so I did have to apologize for it. --Army1987 (t — c)08:56, 19 October 2008 (UTC)
Why do you insist on saying I define them as "anything with nonzero invariant mass"? I don't. Matter is composed of the elementary fermions. If it's composed of elementary fermions, then it's matter, if it's not composed of elementary fermions then it's not matter. End of story. Nothing to do with mass. Nothing to do with pair creation and annihilation. Headbomb {ταλκ – WP Physics: PotW} 15:35, 18 October 2008 (UTC)
I only meant that I don't like it; but that's just me, and the article is fine as it is. (I think that few people are so enthusiastic with Franklin's definition of vitreous electricity as "positive" and resinous electricity as "negative", which forces us to write absurdities such as Cl− to refer to something which is something more than a Cl atom, or that current in metals flows in the opposite direction of the drift velocity of electrons; and probably fewer people like the fact that the ampere is a fundamental unit and the coulomb is derived; but that's the way it is, and no-one is going to change that; so arguing about that is essentially a waste of time, like what I have been doing now.) --Army1987 (t — c)19:17, 18 October 2008 (UTC)
Don't give up so easily. Mass is a scientific word with a good scientific definition, but matter is not. There is no SI definition for "matter", which we might not like, but have to live with. Instead, there's just bunch of POV pushing by various editors, who have a bug up their behinds as to what THEY think "matter" should mean, instead of what people commonly mean, and what the dictionaries say. If you find me a Webster's dictionary (or even any scientific dictionary) which defines "'matter" as "anything made up of fermions", I'll eat the page. SBHarris03:59, 19 October 2008 (UTC)
The article already says that "physicists generally do not use the term matter when precision is needed", so what's the matter? (Sorry for the really bad pun.) --Army1987 (t — c)08:56, 19 October 2008 (UTC)
The problem is that the remaining text gives the lie to that statement, by defining "matter" as fermions, without stating what the problems of that definition are. If physicists really define matter as fermions, they would use the term when precission was needed. The precise definition would be (and this article now suggests that it is): "Any fermion, or collection of fermions, and nothing else." SBHarris20:39, 19 October 2008 (UTC)
The three generations of matter: quarks and leptons.
That is not a reference for the question on the table. If it says "matter," it's only because you added it. It's in the image at right, but it's not in the original. SBHarris01:46, 20 October 2008 (UTC)
Unlike bosons, fermions—the other half of the particle family tree and the basic building blocks of matter- from a NIST press release on fermionic condensates. This site also follows the fermion/matter boson/force division. However this announcement by NASA (announcing the same discovery as the NIST press release) would have Bose-Einstein condensates and Fermionic condensates as the 5th and 6th forms of matter. SpinningSpark21:24, 20 October 2008 (UTC)
I'll just point out quickly that the bosons in Bose-Einstein consensates are clumps of fermions. But yeah, fermionic condensates and bose-einstein condensates are different phases of matter. Headbomb {ταλκ – WP Physics: PotW} 21:32, 20 October 2008 (UTC)
Clumps of fermions and bosons; more bosons than fermions, actually (even if I doubt that the count of gluons is a well-defined concept). --Army1987 (t — c) 12:24, 21 October 2008 (UTC)[But why am I continuing this, anyway? I'm unwatching this page. --Army1987 (t — c)08:46, 22 October 2008 (UTC)]
I agree with what Sbharris is saying. Unlike mass or energy, matter is not a word with any precise scientific definition. It is common to use it to refer to fermionic matter, but there is no physical reason to exclude bosons from its definition (If dark matter turns out to be bosonic in nature, will we stop calling it matter? I doubt). Physicists don't care about that. They use the word as a matter of convinience as long as it is a usefull word to get across the intended meaning. Dauto (talk) 19:28, 31 January 2009 (UTC)
Quizie (to make a point)
Our Sun loses 4 million tons of matter (by all the definitions in this definition in this article) every second. What fraction of this "disappeared" matter is quarks? What fraction is leptons? Add them together and what fraction is fermions? I figure a couple of hundred kg of neutrinos is in there, for a fraction of a millionth of a per cent, or so. If a millionth of a percent of the sun's lost matter winds up as fermions (and indeed never was anything else), what does that say about a fermionic definition of matter? 99.99999+% of the matter the sun loses, is not fermions. SBHarris02:02, 21 November 2008 (UTC)
Sorry, but I don't think even most scientists would nod at you you if you told them that the sun loses 4 million tonnes of mass every second, but no matter at all. This is coming up with a definition which is very far from common usage anywhere. You'll already got this article saying that matter has mass and takes up space; now you want something in the Sun which does indeed have mass and take up space (fermions themselves don't take up space-- they are point particles), but you want this stuff not to count as "matter." Bleh. Baloney. SBHarris01:42, 25 November 2008 (UTC)
Then most scientists are wrong and it's as simple as that, and so is common usage. I provided the refs for this, it's in any and all mainstream or non-mainstream books on particle physics. Gauge bosons are not matter, they don't take volume, yet many are massive. Neutrinos are matter yet they are massless (well they are nearly massless, but that's inconsequential here). I've explained this at least 5 times now, it's not hard to get. Matter = Elementary fermion, and neither mass nor volume is a defining property of matter. That's what Einstein's equation is about, mass is not conserved, energy is.
Let's suppose for a second that somehow matter is defined by mass and volume. That means that no leptons are matter since they are point-like particles. Same goes for bosons since they too are point-like particles. Well you're left with exactly didly-squat because that's all the particles out there. But nearly all of them have mass, which is a sign that they are matter! So you can't have space as a prerequisite. If you go with mass, then you've what is not matter are made of photons, gluons, gravitons, and neutrinos. But the first 3 are gauge bosons, and the last ones fermions. But we know neutrinos have small masses, and it's possible that gravitons and gluons have one too. What then is matter? Photons only? What if they too turn out to have very small masses? Would they cease to be matter?
I really don't think you know what you're talking about, and I don't mean this in an insulting way. Nuclear phenomena are rarely part of everyday experience, and the crude definitions of high school and chemistry textbooks which works for any non-rigorous investigation of what matter is will hold most of the time. But not all the time. In exactly the same way that Newtonian mechanics work just fine usually, they don't when you go to the very small and the very fast, so does the definition of matter as being what has both a volume and mass. Headbomb {ταλκκοντριβς – WP Physics} 02:37, 25 November 2008 (UTC)
Um, I hate to be told that I might not know the subject, by somebody who just got finished saying something like "That's what Einstein's equation is about, mass is not conserved, energy is." Einstein had many equations-- perhaps you're thinking about E=mc^2, which is just a special case of the more general relativistic energy-momentum which shows up when momenta add to zero. In any case, whatever equations you use, a single observer (a single frame) looking at a closed system sees invariant mass, energy and momentum all seperately conserved in the system. Even relativistic mass is (trivially) conserved, since energy is conserved. I don't know what you think E=mc^2 means, but it surely does not mean that mass is not conserved. In closed systems, every kind of mass is conserved unless you let some out! Which means the system isn't closed. Change frames, and the values of energy, relativistic mass, and momentum all change, of course. Only Lorentz 4-vector invariants are do not change under observer-boosts. But those include invariant mass, 4-force, 4-velocity, 4-momentum, and so on, and so on. SBHarris00:07, 29 November 2008 (UTC)
Because rest mass is only non-conserved in the sun because light is let out. If you put the sun in a mirrored box, no rest mass (or any other kind of mass) would be lost at all. Yes, matter, as you've defined it, can be lost, even in a closed system. It is matter, as you've defined it, which is not necessarily conserved in closed systems (electron+positron-->gamma rays. Here your fermionic "matter" disappears, but the system mass is conserved). That is why I think this whole article is ridiculous in trying to define "matter" as quarks and leptons, even though these make up little of the mass in ordinary objects, and even though they are not conserved (when mass is). What is the point in connecting fermions with "matter," when most of our experience with "matter" requires fermions only as chocolate-chip cookies require chocolate chips. They are a necessary ingredient, but they aren't the main one. SBHarris02:33, 29 November 2008 (UTC)
But the sun isn't in a closed mirrored box, that is why it loses invariant mass (which is nigh irrelevant here since we're talking about rest mass, and the sun would still lose rest mass if put in a closed mirrored box). And there are photonless contributions to loss of rest mass too, through solar neutrino emission.Headbomb {ταλκκοντριβς – WP Physics} 03:06, 29 November 2008 (UTC)
A perfectly impermeable box, then. And this box (as a whole) would not lose any kind of mass (invariant or relativisitic) over time, nor energy, though the box-system would lose "matter" by your definition. And that's screwy. You have "matter" being converted to "energy" in this closed system, and both of them accompanied by mass! SBHarris09:22, 29 November 2008 (UTC)
The type of box you put the sun in is irrelevant. You can put the sun in any conceptual box you want, it would still lose rest mass. Mass (not matter) would still be converted to energy, and it would still be irrelevant to any sensible definition of "matter".
This discussion is pointless anyway. The article explains clearly why matter is defined by particle physicists to be what is made of the elementary fermions, it explains clearly why the other definitions are problematic, and why mass is irrelevant to what matter is, and I've got the refs to back me up on this. Headbomb {ταλκκοντριβς – WP Physics} 10:37, 29 November 2008 (UTC)
Mass is never "converted" to energy, thus disappearing as mass. Mass is conserved for any closed system and any single observer/frame. It's a layman's understanding that mass is ever converted to energy, and it's completely wrong. I would suggest reading Mass in special relativity and references therein, such as Taylor and Wheeler. It's infuriating for you to tell me that I don't know what I'm talking about, when you don't even understand the basics. (And as for the popularizations about "matter" coming out of SLAC public relations office, they're worth about what you'd expect). SBHarris18:11, 29 November 2008 (UTC)
I could equally be insulted by your ramblings when you can't even distinguish between invariant mass and rest mass. Mass is converted to energy. That's what is all about. Take beta decay for example. A neutron (~939.57 MeV/c^2) turns into a proton (~938.27 MeV/c^2), an electron (~ 0.51 MeV/c^2), and an electron antineutrino (~0 MeV/c^2). Now comparing what you had before, with what you have after ... ~938.27 MeV/c^2 + ~ 0.51 MeV/c^2 +~0 MeV/c^2 = 938.78 MeV/c^2 which is not 939.57 MeV/c^2! Rest mass () isn't conserved. Where did it go? It went in kinetic energy (). If you're arguing against this, you have self-defeating argument, because that's how the sun loses its mass and how the amount of mass loss is calculated. Since energy is conserved (), then it follows that . We know the solar output () is 3.846×1026J/s, so dividing by -c^2 we get the rate of mass loss (4,307,726,219 Kg/s, or ... 4 million metric tons).
Now you can keep arguing tooth and nail against this all you want, I got the refs for my side. So how about you read Mass in special relativity#Conservation versus invariance of mass in special relativity. To quote the very first sentence "Total energy is an additive conserved quantity (for single observers) in systems and in reactions between particles, but rest mass (in the sense of being a sum of particle rest masses) is not conserved."
Sigh. I believe I actually wrote the sentence you're quoting. "Rest mass" is conserved only if it's "system rest mass." Which is what you get if you (for example) put the components in an impervious box on scales and let them bounce around. If you did that with the sun, its mass would not change from second to second, because you'd measure the mass of the light, also, in the sun's frame (two photons as a system have mass if they're going in opposite directions!). So long as you don't open the box, the system mass does not change.
Now, I specified one observer and a closed system, remember? Saying that rest mass (in the [bad!] sense of being a sum of particle rest masses) is not conserved, is just a short form of saying that mass isn't conserved if you calculate it (wrongly!) as separate rest masses in separate frames, which means moving from one frame (one observer in the initial frame) to a number of other frames (those of each of the 3 moving particles after the decay). But why should it be?
The mass of the whole system (no matter how you calculate it) is what is conserved in closed systems, for single frames and single observers.
Yes, if a neutron disintegrates into three particles, you will find less than a neutron-rest-mass, if you (wrongly) chase after each of the 3 particles to get to their rest frames, and measure their separate rest masses in all those different moving frames, then think you can add up what your three observers found. But that's not a tale of a single observer--it's the tale of 4 observers in 4 different frames, and it's disallowed. I never claimed you could do it.
However, what's true, is that in the original neutron rest-frame, the mass of the system of 3 decay-particles remains the same, even after disintegration. In this easy case, where we stay in the COM frame, the invariant system mass includes both the rest masses and the kinetic energies of the particles/c^2 since the sum momentum is zero. System invariant mass is thus the same number as system relativistic mass, which is also the same as the neutron rest mass, and it's all the name number. Mass is conserved, and in this system, the two types of mass (invariant and relativistic) are the same number.
If you move to a different frame or have a moving neutron (same thing) you will now find that relativistic mass and invariant mass are now different numbers (have different values), but again, neither of them change after disintegration (they simply remain two different numbers, but they are the SAME two different numbers). Again, both kinds of mass are conserved, but happen to differ from each other numerically (since with a moving neutron, they represent different things-- the invariant mass is the neutron rest mass, and the relativistic mass is that plus the neutron's kinetic energy/c^2). SBHarris03:30, 30 November 2008 (UTC)
Box or no box, we're talking about the sun's rest mass, not the invariant mass of everything that's in a mirrored-and-otherwise-impervious-to-any-sort-of-energy-exchange type of box. And since there's no actual box around the sun (no that it's relevant, because we're talking about the sun's rest mass, and not the invariant mass of the "sunbox"), then there's nothing to "contain" the photons' energy. Your argument is self defeating anyway, you're talking about the sun's mass loss of four millions tons per second being a problem for the elementary fermion definition of matter, then claim the sun doesn't lose mass. So which way is it then? Headbomb {ταλκκοντριβς – WP Physics} 22:10, 30 November 2008 (UTC)
The sun loses mass because with any boundary you draw around it, 4 million tons of light and neutrino mass move through that boundary each second, and are gone. The Sun's "rest mass" is a tricky concept, as is the "rest mass" for any unbound system (it requires definition in every case, unless you decide it should be the invariant mass). I wish I hadn't chosen the Sun, as the positron-electon system works better to illustrate. If we count electrons and positrons as "matter" then when they anihilate, the system matter disappears completely, but the system mass does not. It's defining "matter" in this way as something non-conserved, that I don't like. That doesn't happen with mass unless you change observers or open the system. But matter, as you've defined it, is up for grabs to turn into matterless mass. And most of ordinary objects, under this definition, are supposed to be composed of this mattterless mass. That's just not in keeping with historical understanding of the term "matter." SBHarris23:19, 30 November 2008 (UTC)
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. They occur in “generations” of two related pairs with differing electric charge—(+2/3, -1/3) for quarks and (-1, 0) for leptons (see chart above). Ordinary matter is composed entirely of first-generation particles, namely the u and d quarks, plus the electron and its neutrino. But the third-generation quark doublet seemed to be missing its charge +2/3 member, whose existence was inferred from the existing pattern. In advance of its sighting, physicists
named it the top (t) quark. Thus began a search that lasted almost twenty years.
What are the "inelegance problems"? Do we drop the term "energy" because it doesn't serve to classify elementary particles? This subsection should be deleted, or modified to form some connection to the later statement in the following subsection: "This definition of matter means that mass is not something that is exclusive to matter." Brews ohare (talk) 18:30, 30 November 2008 (UTC)
The "inelegance problems" is the non-cladistic character of matter under the mass definition. Under the standard model, you would have fermions which are matter (quarks and electron like leptons), but not neutrinos (which would be matter under the extension of the standard model), and you would have bosons that are matter (W and Zs), but not photons and quarks, although maybe quarks would be.Headbomb {ταλκκοντριβς – WP Physics} 22:00, 30 November 2008 (UTC)
I have deleted this section, and re-written large portions of the article, adding innumerable citations and a few images. I believe the issues are now clear, though I have not brought up cladistics. Please take a look. Brews ohare (talk) 16:51, 1 December 2008 (UTC)
Change of image
I switched the image of Phosphorus sesquisulfide to one of DNA. In my view, no-one cares about Phosphorus sesquisulfide, while DNA is a very significant molecule very well known. Although not expressed, DNA also is interesting as a modern segue into the ancient philosophical debates about "matter" vs. "spirit"? Brews ohare (talk) 17:58, 1 December 2008 (UTC)
Defining matter
I've rewritten this article extensively. I've included the point about the contribution to mass of interaction energy introduced by SB Harris with supporting citations. I reworded his statement to fit more closely with the citations.
I've also stated that if a nucleon is "matter" then so is the glue that holds it together. That statement means that gluons are counted as matter if they bind a composite together. They are excluded from the matter definition only if they are outside of such a composite.
It seems to me this view is necessary to avoid some ridiculous ideas like a neutron is partly matter and partly not. From that stance, an atom's partly matter and partly not. That doesn't seem to fit very well with matter as everything made of atoms.
However, including the interaction energy is a bit nasty, as a gluon classed as matter in an equilibrium state could become declassified in a transient decay. So I'm unclear just what to do with this in an unstable configuration.
Is there more "matter' in a compressed spring than in a relaxed one?
I would certainly say there is more matter in a compressed spring; but the same number of atoms. There is more matter in a uranium atom than in the two fragments it makes when fissioned, but the same number of nucleons. Here matter is being used synonymously with the use ordinary mass in ordinary objects, which falls within the definition (matter has mass and takes up space, with the provision that we dont' have to be too finicky about knowing which space is taken up, that is, exactly where the mass is) SBHarris02:07, 30 January 2009 (UTC)
I agree. But what about light in a box? E.g. the equilibrum black-body radiation in a cavity in a hunk of matter? Is that matter? It does add to the mass of the box. And what about light outside the box? Not matter any more? Dicklyon (talk) 03:27, 30 January 2009 (UTC)
Good question. And one of the reasons why this isn't going to be a neat definition, and probably should be abandoned as a scientific one, unless you chose something else (I suggest "matter" = "invariant mass" below). The massless energies of gravity and electromagnetism aren't counted as "matter" when going from here to there, but they do add mass when confined and in fact most of the mass of objects is intrinsically massless fields (fields of massless gluons), if you look hard. Mass is such an odd thing. It's sort of signal that "here's some energy that you can't find an inertial frame to get away from, or make go away." But if you can find such a frame, we call that energy massless, and it doesn't contribute to the mass of matter. Perhaps in discussing "matter" we're really discussing that fact that lack of a inertial frame to make it go away (as happens for every individual photon), and which frame where energy is minimized but non-zero "pins down" the energy, and it is the "being pinned down" that makes it matter, not what kind of particle it is. So two photons in a box (even one in a box) are matter, and can be weighed, but one photon flying free isn't. Even two photons flying free in different directions have a system invariant mass, and I would say are thus matter, albeit a funny kind. Hard to say what space they take up, but it always is. The mass is the system invariant mass, which (to me) is the closest definition in classical physics to the idea of "matter", not "fermions." Matter is invariant mass. SBHarris20:45, 31 January 2009 (UTC)
Nope. I doubt that anybody is seriously thinking about the question. Anymore than coming up with a scientific definition of "stuff." SBHarris01:24, 1 February 2009 (UTC)
SB, if you don't have a source for your concept of matter, could you at least give me a place to start reading about the view you offer? You seem to grasp what the problem is, and I am curious about how you got to it. Thanks, Ocanter (talk) 02:12, 29 April 2009 (UTC)
Unlike the words mass and energy, the word matter doesn't have a very clear scientific definition. Physicists use the word as a matter of convinience, as a mean of comunication. The word stuff would indeed be just as fine. Dauto (talk) 01:47, 1 February 2009 (UTC)
Dauto, it is becoming more and more clear to me that you are probably correct. However, if it is true, then there should be some academic source that states this, and we should put it in the lead paragraph. Does anybody have such a source? Ocanter (talk) 15:09, 29 April 2009 (UTC)
Any definition that equates matter and mass or that defines matter in terms of mass, is IMO out of touch with current use of the term. Matter happens to have mass, mass does not define matter. If you define matter as "what has mass", then the only thing that is not matter (under the SM) are photons, gluons, gravitons (if they exist) and neutrinos. But we do know that neutrinos have mass, so then they would fall under "matter". What if gluons, photons and gravitons (or somet of them) turn out to have masses as well? The only definition of matter that avoid all these problems is the one where matter is what is made of elementary fermions. And yes that would, in a way, imply that neutrons are part matter and part fields. Which they are, else the quarks would fly away from each other and you wouldn't have a bound state to call a neutron, exactly like electrons would fly away from the nucleus if photons didn't exist. However, no one has a problem reducing atoms to proton neutrons and electrons, calling those things matter, leaving photons out of the picture. The only thing different is the scale of things. Photons introduce masses differences of a few eV at best, while the weak/strong introduces mass differences of the order of MeVs. Do photons became matter if we're speaking of an electron orbiting nuclei made of 10^6 bare protons?
Mass is a completely different topic, and its definition never comes in contact with what matter is. Mass is related to how hard it is to accelerate something. Let's not confluate the two. Matter is what is composed of elementary fermions. Bosons contribute to mass as well, but are not matter. Headbomb {ταλκκοντριβς – WP Physics} 03:38, 1 February 2009 (UTC)
And of course we also have the equivalence of mass and energy, so if mass were the defining quality of matter, then it seems we would be forced to say that matter is energy, and we could dispense with one or the other of the two concepts, matter or energy. I agree with Headbomb that the two concepts are different, and that spin-statistics theorem, leading to the Exclusion principle, is really the key to the distinction. But we really need something authoritative from the literature on this issue to settle it for the encyclopedia. Does anyone know of sources addressing this question? It seems it must be out there. Wwheaton (talk) 08:46, 1 February 2009 (UTC)
Good luck with findind a reference for that. While you are at it, why don't you give some thought to where should one place the Higgs boson in your neat little scheme. Is the Higgs matter or not? Dauto (talk) 15:46, 2 February 2009 (UTC)
It's already referenced in the text. As for the higgs, it's not an elementary fermion, so it's not matter. See the image on the right . However, I don't know how this diagram would include the higgs, since it doesn't look like the higgs is carrying a force, but I may be wrong about that. Headbomb {ταλκκοντριβς – WP Physics} 18:14, 2 February 2009 (UTC)
The exclusion of the vector bosons from the definition of matter is quite arbitrary but not entirely unreasonable. The exclusion of the Higgs boson (just because it happens to be a boson) seems to be unjustifiable.
The bottom line is: whatever definition we can come up with will have very little physical content and will be a matter of taste that cannot be decided by any physical principle. I think bosons should be included and I haven't seen any good reason to exclude them so far. Why the prejudice against bosonic matter? Dauto (talk) 23:14, 2 February 2009 (UTC)
Dauto - please remember that it is not for Wikipedia to propose (or "come up with") a definition, but rather to report and explain the currently accepted definition. Any "taste" or "prejudice" of the editors in this discussion is irrelevant. As noted by both Headbomb and Wwheaton, the article now makes clear (with some sources) that the currently accepted definition corresponds to massive fermions. It also explains that the restriction to fermions is related to the traditional idea of occupying volume, since we know that this is a consequence of the Pauli exclusion principle which applies only to fermions. We may be able to improve the explanations, but we should not change the definition without sources. (One caveat: "dark matter" and "exotic matter" are of unknown nature, so it may someday turn out that they are not really matter as currently defined. If so, future physicists may have to choose between renaming these entities and re-defining matter. But not in an unsourced discussion on Wikipedia!) Dirac66 (talk) 02:45, 3 February 2009 (UTC)
Isn't that exactly my point? That there isn't a currently accepted definition for matter? Wasn't I clear enough? Dauto (talk) 14:59, 3 February 2009 (UTC)
You seem to argue that since there isn't a "currently accepted definition for matter" (I disagree, as the elementary fermions is widespread) that we can do some original research on the subject. Maybe the exclusion of the higgs is unjustifiable, but unless you find reliable sources saying so, then you might as well be trying to argue the moon is made of cheese.Headbomb {ταλκκοντριβς – WP Physics} 11:05, 12 March 2009 (UTC)
The current definition in the header is original to wikipedia. The cited source does not support it. Besides, it is a rather simple-minded attempt to displace the problem. "Matter is made of whatever the elementary particles of matter are made of." Of course it is. "Clay is made of whatever tiny bits of clay are made of." It would be better to say, as I think you mean to say, that matter is a structural relation among fermions, which are, in your view, not themselves "matter," but something else? SBHarris's comments about energy and reference frames were interesting. Can we find a source for them? Ocanter (talk) 02:03, 29 April 2009 (UTC)
Headbomb, thanks for replying and for supplying the requested citations. However, your source once again fails to sustain your claim. The authors of that elementary and somewhat dumbed-down textbook are very careful to avoid giving a definition of matter. On the contrary, they merely assert that there are two "fundamental types of building blocks." The obvious next question is whether these "building blocks" are themselves "matter." If they are, then we can turn around and ask the same question: "A quark, like a rock, is a piece of matter, but what is matter?". If the building blocks are not themselves "matter," then it seems a reduction of matter to form (in the Aristotelian sense) has been accomplished, and matter becomes merely a complex of relations between immaterial elements. I am not opposed to any way it might turn out; I just want to know the truth. It sounds like we really don't have a good definition of matter, as Dauto and SB have stated. Ocanter (talk) 15:26, 29 April 2009 (UTC)
(unindent) "Building blocks and stuff made of the building blocks" is what matter is. I don't care much about what Aristotle had to say about forms and immaterial elements. See also Dirac66's 02:45, 3 February 2009 (UTC) post.Headbomb {ταλκκοντριβς – WP Physics} 16:59, 29 April 2009 (UTC)
Headbomb, you keep putting quotes around phrases of which you are yourself the author. You do not have a definition with a source. I tried to post one from OED, and you immediately deleted it. Can we get a third opinion here? Ocanter (talk) 18:11, 29 April 2009 (UTC) Ocanter (talk) 18:14, 29 April 2009 (UTC)
First keep your petty attacks to yourself. I am well versed in philosophy, I simply don't care what Aristotle had to say about things. Greek philosophers, while they started many of the concepts we now use, are de facto irrelevant when it comes to understanding the current version of things. Second, quotation marks are not solely used to indicate quotation. See Words as words. Third, for support of this definition of things, I gave you relevant citations many times (and if you bothered to look them up, we wouldn't be here). So once again, the two used by the article:
B.Povh et al., page 2. (Currently ref 3/21):
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.
If you need more, you can look into
K.A Peacock, page 125 (currently ref 6):
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 (currently ref 38):
Establishing the quarks and leptons as the basic bits of matter is only part of our revolution...
Thanks for reprinting those citations. I had already read them, but it may be useful for others to see. I propose that we change the lead to say exactly what your cited sources say: matter has mass and is believed to occupy space according to the Pauli exclusion principle, and the elementary particles of matter are classified as quarks and leptons. To say more than that is original research. I ask again for a third opinion. Ocanter (talk) 21:45, 29 April 2009 (UTC)
But we're not saying more than that. So what's the problem? And matter is not defining has having mass (it happens to have mass, but it's not a defining property). This is discussed in the "Discussion" section. Headbomb {ταλκκοντριβς – WP Physics} 03:34, 30 April 2009 (UTC)
I hope you will someday reconsider my suggestion to read Aristotle, not the physics so much as the logical works, esp. re. accidental vs. essential properties. Currently, the lead says, "Matter is what is made up of atoms and molecules, and by implication, is made up of what atoms and molecules themselves are made of." I suggest we change this to, "the elementary particles of matter are quarks and leptons." The former states a definition (without an appropriate source, I maintain), while the latter is common knowledge, and is sustained by your sources. Ocanter (talk) 22:48, 30 April 2009 (UTC)
The former is common knowledge. The later is common knowledge amongst physicists. Giving the straight Q&L definition doesn't make people understand why it was defined as Q&L, so you need some link between the common version of "atoms and molecules" to "quarks and leptons". Headbomb {ταλκκοντριβς – WP Physics} 00:22, 1 May 2009 (UTC)
If I'm not mistaken, the first is actually false; there is matter that is not contained in an atom or molecule (unless free fermions are not "matter"?) Ocanter (talk) 20:03, 1 May 2009 (UTC)
Your language is confusing. The first is "What atoms and molecules are made of". Aka protons and neutrons (themselves made of quarks) and electrons (a lepton). It's false if you read it like "ONLY electrons, protons and neutrons are matter, anything else is not". It's not false if you read it like it's written (aka matter is what atoms and molecules are made of). The "second" definition is simply a more rigorous phrasing of the same thing. Headbomb {ταλκκοντριβς – WP Physics} 00:40, 2 May 2009 (UTC)
It is false if you read it the way I do, and it is unclear even if you don't read it the way I do. Here is what is written:
"Matter is what is made up of atoms and molecules, and by implication, is made up of what atoms and molecules themselves are made of."
This is a compound sentence. Here are the two clauses.
1) Matter is what is made up of atoms and molecules.
2) Matter is made up of what atoms and molecules themselves are made of.
The first sentence, I think we agree, asserts that some matter is made up of atoms and molecules. However, it sounds like you also mean that all matter is made of atoms and molecules. I think this is false. I don't think I am reading it wrong; I think it is written wrong.
The second is true, in a trivial way, if you mean "some matter," since atoms and molecules must be made of what atoms and molecules are made of. If you mean "all matter" (which would seem to require the "what is" here instead of in the previous clause), it could function as a definition, but it would be, as I originally objected, vacuous.
I am beginning to see that you really don't see the problem with the definition, as you just suggested we should read it: "matter is what atoms and molecules are made of." I would first suggest that you change the text to actually say what you think it says: 3)"matter is what atoms and molecules are made of." Then you will have:
4) Matter is made up of atoms and molecules. (reiteration 1)
5) Atoms and molecules are made of matter. (transposition 3)
I would then suggest you take a long look at it and decide if you really prefer that to what your sources say: "Particles of matter are called fermions." I'll let you, and the rest of the editors, decide which is better. As to how to explain that atoms are composed of protons and neutrons, and that protons and neutrons are composed of quarks, I will leave that to your capable hands. Thanks for your attention. Ocanter (talk) 21:05, 4 May 2009 (UTC)
I continue to favor a definition based on the elementary fermion/boson disjunction, with no essential reference to mass/energy, which is a separate issue that all particles share alike. All particles share the same E2 = p2 + m2 rule for mass/energy. But without the exclusion principle, atoms and the ordinary matter in our world would be utterly different. Notice how bosons composed of elementary fermions, like 4He, do occupy space, in the sense of the exclusion principle. And note also that there is no way to build a composite fermion out of bosons. These seem to me to be deep truths: one says we cannot make "matter" out of elementary bosons, and the other suggests that even composite bosons, if built up of elementary fermions, never lose their character as matter.
But I think that for the purposes of this article, the discussion should proceed from top (commonplace) to bottom (esoteric), starting with the familiar e, p, & n, which are the basic entities needed to describe 99% of the matter that makes up our everyday world. Every even slightly educated person should be familiar with these, and how they build up atoms and molecules.
Then, in a more advanced section, we might discuss mass and energy, based on E2 = p2 + m2, and discuss massless and massive particles, and the quanta of force fields. All particles have energy, and therefore mass, but not all particles are matter: the spin/statistics theorem governs that.
Only after that, need the deeper questions of quarks, leptons, Z0 (a bona fide massive elementary boson), and gluons (massless, yet [color] charged!) be addressed. I suppose it should be possible in principle to make a Bose-Einstein condensate out of an ensemble of Z0's or even Higgs particles, but does anyone know for certain? And then of course there is the question of Dark Matter. But no pedestrian needs to know the details abut all of these. For similar pedagogical reasons, in mathematics we teach arithmetic first, rather than group, ring, and field theory. Best, Wwheaton (talk) 07:28, 2 May 2009 (UTC)
The matters are waves (the matter wave) is not mentioned and I think this is a very important part. Could anyone please add something? Thank you. (I can't because of my poor understanding for both Physics and English;-) ) Matthew 百家姓之四Discussion 討論10:33, 12 March 2009 (UTC)
We could add a sentence such as "At the microscopic level, the constituent "particles" of matter such as protons, neutrons and electrons are actually matter waves (or fields) which obey the laws of quantum mechanics." I'm not sure where in the article to insert this; possibly in section 1.3 Scientific definition or 1.4 Discussion and background. Dirac66 (talk) 16:03, 12 March 2009 (UTC)
It is important to appreciate that the wave/particle duality of matter is essentially that same as for fields, light in particular, except for issues related to even/odd spin and the Exclusion principle. Thus, while it certainly is important, it really has nothing in particular to do with matter, per se. Wwheaton (talk) 00:08, 8 May 2009 (UTC)
What is matter?
Hi, i would like to know if there is a more General description on Matter and specificaly electricaly charged matter? I'm doing a self study on Electricity, and defenately did not know what i was geting myself into.... As the word electricity is a vague term, but my aim is to atleast know something about everything contributing to electricity and to basicly understand it. Please note that i do not have a Degree in any field - i only share your eagernes to learn.
Thanks Neels —Preceding unsigned comment added by Kroucacj (talk • contribs) 18:56, 22 March 2009 (UTC)
Isn't such a thing supposed to be described in the article? Or are you saying that we don't technically know? Faro0485 (talk) 04:35, 29 April 2009 (UTC)
No, I'm saying that if Kroucacj wants to know about "charged matter", his/her best best it to pick up introduction books on electricity. "Charged matter" is not very special, it's simply matter that responds to electromagnetic forces. But that's not how hisher question seems to be asked, he/she seems to be asking about electric phenomena such as conductivity, resistance, etc... This is kinda off topic. I would point him/her to electromagnetism (or something like that), but that article will not be as helpful as a good vulgarisation book. Headbomb {ταλκκοντριβς – WP Physics} 05:59, 29 April 2009 (UTC)
Revert
I revert to this version because I don't exactly understand Brews Ohare's revert ("add citations requested by BriEnBest & reverted by Headbomb; revise unsupported statements").
BriEnBest asked for something supporting a sentence made to the effect that "matter was subset of mass", which is a claim not found in the lead anymore, at least not directly. The citations are commented away if someone wants to use them or to reintroduce the "matter is a subset of mass" claim (an awkward phrasing to say the least). Concerning the "unsupported statements", I really don't see what's not supported. The lead reflects the rest of the article, which is referenced left and right as far as the lead content is concerned.
This also reverts the "and the binding energy" part, which is more relevant to mass rather than matter itself. Every electron comes with a photon field, and it that field is not considered matter. The gluon field of quarks is no more matter than the photon field of atoms is. Headbomb {ταλκκοντριβς – WP Physics} 02:07, 11 May 2009 (UTC)
I interpreted BriEnBest's request differently, as requesting authority that energy and matter were not necessarily the same. That is a relevant point, whether he has been interpreted correctly or not, and these references support that point. Also, photons do have mass, just not non-zero rest mass.
The LEAD was not quite right. All energy is associated with mass. If you're going to have matter as "energy which is associated with MASS," it must be energy that is associated with a special type of mass: either with rest mass, or else the invariant mass of bound systems. The invariant mass of unbound systems does not work, as it gives systems of photons mass. However, most people have agreed that hot objects not only are more massive, but also contain more "matter" in usual sense of "stuff" (though not more atoms). But if we're talking about invariant mass of BOUND systems only, we still have hot objects being more massive AND containing more "matter." How does this compromise suit? W bosons may be a problem if you don't want them as matter, but they are short-lived, so how about "Energy associated with long-lived rest mass, or bound invariant mass"? This isn't easy, is it? Actually, I think it would be easier to keep the former definition, and just define the W boson as matter. SBHarris05:57, 11 May 2009 (UTC)
You're conflating mass and matter again. The two concepts are not equivalent nor even related. Matter happens to have mass, mass is not matter. Matter is substance, namely elementary fermions or stuff made of them. Energy or mass are not substance, they are properties. Headbomb {ταλκκοντριβς – WP Physics} 06:57, 11 May 2009 (UTC)
No, for you want arbitrary amounts of ordinary objects (the fermions in them) to be made of what you've decided is the "substance" even if it doesn't contribute most of the mass, and isn't the atoms, etc. That's a possible definition, but I think it's counterintuitive and not historical. As in: "Here's a 100 kg rock. Is it not remarkable that only 5 kg of it, is matter!" Yes, I would say it's pretty remarkable. SBHarris01:07, 12 May 2009 (UTC)
Headbomb: As I read the present form of the article, your revisions have introduced exactly the problem you mention: you yourself suffer from this very confusion. This statement: However, energy cannot always be related to mass; photons possess energy (see Planck relation), but are massless.
which you have re-inserted twice now, is nonsense. The point of the paragraph is to say that matter and energy are distinct, and that photons are an illustration of this fact by virtue of having energy but not being a component of matter. That is what the suppressed references support as well. You are out to lunch on this one. Brews ohare (talk) 13:58, 11 May 2009 (UTC)
In addition the statement However, energy cannot always be related to mass that you have reinserted several times after it was corrected, is out-and-out nonsense, contradicting relativity. Brews ohare (talk) 13:58, 11 May 2009 (UTC)
I have included a citation to the Max Jammer discussion of relativistic vs. rest mass. Both Rindler and Jammer agree that E=mc^2 is about relativistic mass, not rest mass. That view is supported in Mass in special relativity. Brews ohare (talk) 18:00, 11 May 2009 (UTC)
Not really (I know because I wrote some of the article about mass in special relativity). E=mc^2 is ALSO a special case of the energy-momentum relation, whenever momentum is zero. Which covers many cases. Not only resting masses, but any system of masses when momentum sums to zero, even if parts of the system are moving (in other words, the system as viewed in the center of momentum frame). For example a tank of hot gas, as viewed in the frame where it can be weighed (and thus its COM frame). Indeed, any ordinary object, which is heated or cooled, has E=mc^2 in the frame where you can weigh it. And this weight varies (in theory) with the heat you put in or draw out. In all these cases the "mass" is the invariant mass of the sytem. The question before us is: does a hot object have more "matter" in it, than when it was cold? SBHarris00:50, 12 May 2009 (UTC)
If this example of a photon is a poor example to show energy and matter are not coincident, let's just drop the example (and all the flack over it). Brews ohare (talk) 03:40, 12 May 2009 (UTC)
"In common usage, matter is anything that has both mass and volume (takes up space)." So electrons aren't matter then? Surely matter is anything that possesses the property of proper mass (or "anything that has mass" in terms suitable for the first sentence of a widely read article)
"the particulate theory of matter, which in the 19th century was taken to say that matter is what is made up of atoms, thought of at that time as irreducible constituents of matter." You'd have to be right at the very end of the 19th century for that statement to be true. Why introduce an outdated theory in a bad way only to shoot it down?
"Energy and mass are connected by the equation E = mc2, which means mass can always be related to energy (see Mass–energy equivalence)." Mass can only be completely converted to energy if you happen to have enough antimatter handy, something which this universe seems to be lacking. Otherwise, you can make matter appear to have more mass, but can't reduce its (apparent) mass below a certain limit.
"However, energy cannot always be related to matter: for example, photons possess energy (see Planck relation); however, photons commonly are distinguished from matter." Exactly, because no observer will perceive photons as having mass: that is the distinction.
Several definitions are given in the article. The common usage definition is exactly that, and of course is subject to dispute in more demanding context. Arguing over common usage is not productive. It is what it happens to be. The other definitions are more particular.
The "particulate theory" is not introduced as outdated, but as the initiation of the modern definition. The only thing that has changed is the idea that atoms are indivisible, which is not critical.
Relating mass to energy does not imply complete conversion is possible, or indeed that any "conversion" is possible. It just means that energy and mass are related according to the equations of relativity.
Photons have momentum hν, not mass = hν/c2. The full equation is E2 = p2c2 + m2 0c4. The momentum term (p2c2) is equal to (hν)2, the mass term is zero. Photons do not have mass, photons have energy and momentum. Saying they have mass hν/c2 is something kids in high school would do. Headbomb {ταλκκοντριβς – WP Physics} 01:35, 12 May 2009 (UTC)
Matter consists of real fermions together with those virtual particles which are necessarily associated with them. JRSpriggs (talk) 01:29, 12 May 2009 (UTC)
But it's not the same "amount" of virtual paricles. For example, a mole of helium gas molecules (He) has the same number of fermions as a mole of deuterium molecules (D2), but the two have different masses. The deuterium is more massive by 6 parts per thousand (6 grams per kg) and that's the mass that would be released as heat if you fused it to helium-4. That 6 grams in every kg is virtual particles of some kind. But it's not even the same kind. For every kg of D2 you fuse, you destroy 12 grams of virtual pions, and create 6 grams of virual photons, and the 6 grams available as heat, is the difference. And even that just sits there as 6 grams of kinetic energy, if you fuse 1 kg of D2, and don't let it out of the box. Six grams of heat = 6 grams of kinetic energy of post-fussion plasma. Now, how much of all this is "matter"? SBHarris02:15, 12 May 2009 (UTC)
This discussion is pointless, as the only reason for raising the examples was to point out that neither mass nor energy is coincident with matter. If the examples create more heat than light, let's just forget about having any examples of this distinction. Brews ohare (talk) 03:42, 12 May 2009 (UTC)
More heat than light, ha! Good one. Seriously, examples are supposed to provide "light" by causing a dawning of understanding. I personally dislike a definition of "matter" in which 95% of stuff around me, including myself, is not regarded as "matter." We invented the term to describe ordinary stuff, and if it won't EVEN do that, what good is it? Yet the definition invariant mass of things where "thing" means a bound system or object, is very close to what we have meant historically by "matter." It still leaves out light, unless it's trapped light. It includes (bosonic) fields, but so what? Most of ordinary "stuff" is bosonic fields! I can live with it. I suggest that this at least be one of our "bullet point" proposed definitions. If you like "fermions" for another proposed bullet point definition, I can also live with that (I'm easy), so long as you point out that this leaves out 95% of "stuff," and is thus QUITE different from the invariant mass of things definition. SBHarris04:42, 12 May 2009 (UTC)
But it doesn't leave out 95% of the stuff, unless by "stuff" you mean "mass". You have no problem saying photons aren't matter, yet photons fields are just as bosonic as gluon fields are. Mass is not "stuff", mass is a property of stuff, to the same extent that kinetic energy or spin is not "stuff".Headbomb {ταλκκοντριβς – WP Physics} 05:08, 12 May 2009 (UTC)
Understand, but invariant mass (what I can weigh) is a property I expect of "matter." A little mass with no matter is bad enough, but now we're going to go for most of mass and volume in ordinary objects as non-material. We're certainly going to have a problem with the idea that matter is what has (weighable) mass and takes up volume, if now we then want to add that most of what gives ordinary objects their mass and volume is NOT matter. Is not even an example of "matter"! Again, very unhistorical. SBHarris05:22, 12 May 2009 (UTC)
Yes but this is all explained. "Mass and volume" is the common layfold understanding ("historical"), "stuff made of atoms" is a more "rigourous" version of it (it is at this point that mass is left out), but this has to be revised in the light that atoms are divisible. If atoms are matter, than so are the stuff that comprise them, protons, neutron, electrons (photons are left out). If protons and neutrons are matter, than so are quarks, as quarks form protons and neutrons. Leading to quarks and leptons, aka the elementary fermions. At this point we understand that "volume" is a result of Pauli's principle, and that mass is simply a result of fermions having some instrinsic mass, plus some dynamic mass which results from internal kinematics and the interaction fields. Headbomb {ταλκκοντριβς – WP Physics} 05:38, 12 May 2009 (UTC)
Comments by Timothy Rias
It isn't completely clear to me what the exact issues are here, but some comments on several things that have been said:
About mass vs energy; mass and energy are both properties of particles/fields/etc. They are related but distinct properties. Energy is the zeroth component of a momentum four vector, mass is its norm (at least up to a sign depending on convention). In dimensionless units this means that mass and energy are only equal when the 3-momentum is zero.
About defining matter as fermions, that is very odd since it implies that a glueball is not matter, nor is a black hole, and also excludes certain types of hot dark matter.
Just as a reference note the cosmological definition of matter: anything with equation of state parameter w=0. (e.g. universe in which most material has this equation of state is called matter dominated) This is used in contrast to "radiation" (stuff with w=1/3). This usage isn't anything near universal, since other people refer to the same two concepts as non-relativistic and ultra-relativistic matter. (TimothyRias (talk) 12:07, 12 May 2009 (UTC))
The issue regards "ordinary matter" as opposed to more exotic forms, which the article treats separately on a case-by-case basis. Brews ohare (talk) 12:47, 12 May 2009 (UTC)
An editor has requested a third opinion regarding a dispute about this page
The {{3O}} template was removed since this dispute was not listed at Wikipedia:Third opinion. 05:02, 13 May 2009 (UTC)
It would be most helpful if the points you wish to discuss were clearly stated here, rather than leaving prior comments to be sifted, possibly resulting in an incorrect view of the issues. Brews ohare (talk) 03:22, 12 May 2009 (UTC)
I came to this talk page as it is listed on WP:3O as needing attention, but there does not seem to be a suitable summary of the dispute nor the two sides to it. Furthermore, a 3rd opinion is for articles where there are two deadlocked editors and a third opinion is required. I can count 6 users in this discussion in the last 48 hours:
Brews ohare
TimothyRias
Headbomb
sbharris
JRSpriggs
Physchim62
I would give the conversation a bit longer to crystallize to a consensus due to the fact there are a number of editors involved and we can't all spend all our time on wp. After all, WP:There is no deadline. Finally, there are a large number of edits still happening to the article, can I suggest all editors look at Wikipedia:BOLD, revert, discuss cycle and concentrate their efforts on discussing here rather than carrying on what could be interpreted as an edit war?!
If after a while you are still struggling to reach consensus then perhaps you could try WP:RFC or ask for further comment from WikiProject Physics, which some of you seem to already be involved with. I will remove the tag from the top of the article and its listing on WP:3O. I wish you all the best of luck in reaching a new consensus, if you need anything else please contact me on my talkpage. Cheers, Bigger digger (talk) 15:28, 13 May 2009 (UTC)
Thanks. This discussion has been hot for many months, and no one has been able to settle it by reference to external definitive sources. I have just asked for wider involvement from the physics community here, to help us close it off. It seems to me the three choices are:
The elementary fermion/boson distinction (which I favor)
Another definition, I guess based on non-zero rest mass, but I am not sure this branch has only one strand(?)
No consensus possible, as no external authoritative community sources exist. At the moment this seems to be the most likely situation, unsatisfactory as it is.
It's quite clear that there are a number of authoritative sources with differing opinions/definitions. This is probably a simplistic view (I'd agree with the too technical banner at the top of this talk page!) but there's no harm in describing the different definitions, noting that the community doesn't have a single view (which would be aided by a suitable source) and leaving it at that. I cross my fingers! I also wrote the following in the edit summary, which seems appropriate: "If there's no expert consensus then the article should reflect that". Bigger digger (talk) 17:57, 13 May 2009 (UTC)
No, the solution is for someone involved in the dispute to list the dispute. I'm not involved, so the right thing for me to do is to remove the template. BrianJasonDrake06:48, 17 May 2009 (UTC)
This article's factual accuracy is disputed.
It would be most helpful if the points you wish to discuss were clearly stated here, rather than leaving prior comments to be sifted, possibly resulting in an incorrect view of the issues. Brews ohare (talk) 03:22, 12 May 2009 (UTC)
I think you overstate the case a bit. Editors have lives besides Wikipedia, may wish to think further about the issues others have raised, and may wait for others to comment. This discussion has not been resolved for months, so I think it a little premature to declare "nothing left to debate" in two days. As TimothyRias's comments below show. It certainly is not settled consensus. Let's allow at least a week of agreement before declaring settled consensus, or deciding how to deal in the text with irreconcilable differences. Wwheaton (talk) 13:57, 18 May 2009 (UTC)
Definition of matter
In my view this article is being a bit bold the subject of defining 'matter'. Matter seems to be one of those terms that get used frequently, but has no universal exact meaning. Different fields in physics and chemistry tend use the term for slightly different things. These concepts all have stuff in common and somehow satisfy a common sense definition of matter (e.g. all would agree that a piece of wood is matter), but there seems to be no exact formulation of what should be called matter. This article then should be clear about this ambiguity from the start. It should be discussed in the lead's first or second paragraph and at the start of the definition section.
For good measure some different uses of the term matter:
In the particle physics, it is often said that the quarks and leptons describe 'matter', while the gauge bosons describe 'forces'. It is often left ambiguous whether the Higgs boson is to be viewed as matter. Alternatively, sometimes any field that is not a gauge boson is considered to be a matter field.
In the context of general relativity, 'matter' is simply anything that contributes to the stress-energy tensor (and thus appears on the rhs of the Einstein equation). Note that this definition does also include things like photons, and (static) electric fields to be matter. In common terms this can be expressed as "matter is anything that exists somewhere in space".
When cosmologist talk about the 'matter contents of the universe' they usually mean matter in the GR sense. However when they talk about a 'matter dominated universe' they have a more narrow definition in mind, namely anything whose energy density scales with the cube of the scale factor. It is thus differentiated from 'dark energy' and 'radiation'. Note that in the later definition a hot neutrino gas would no be considered 'matter'. At other times stuff that follows this definition is called non-relativistic matter.(TimothyRias (talk) 08:50, 18 May 2009 (UTC))
I agree we have to accept that different knowledgeable sources use the term differently. I still think we should not dive into the heart of these frontier issues at the beginning, but only note that they exist in the lead. Then cover the simple {p,n,e} story (including much of physics, all chemistry, biology, etc) in the first section, then in a later section discuss
E2 = p2 + m2
and massless particles (ie, the m = 0 case, of course) to show why one cannot really identify mass with matter without simply admitting the entire GR source term and declaring matter is just E/c2, which I think is clearly unsatisfactory, as there is a distinction to be made, not obliterated. The exclusion principle I would discuss at this point, and clarify why "taking up space" and "being in space" are not the same thing. Also discuss why the particle/wave distinction offers no help, since if applies to everything. Then the issues about the Higgs, the status of dark matter, and dark energy, really seem to lie at the edge of what is settled science, or at least generally known, and I would place them in a final section, admitting ignorance and the unsettled state of our understanding, assuming no flash of clarity and agreement arrives to save us in the meanwhile. Wwheaton (talk) 14:36, 18 May 2009 (UTC)
(Bill, first of all this doesn't seem like a reaction on the paragraph above it, was it your intention to reply to my other remark above?)
I think we should not give readers the idea that there is a well established uniform notion of 'matter'. The article should make clear from the get go that there is no single exact definition of 'matter' in the sciences. It should then continue the explain the general gist of the various concepts. (i.e. matter is the stuff that things are made off) Then it should summarize the different definitions (preferable going from accessible to more technical) explaining how they differ and how they satisfy the general gist.
Also just as a specific reply: At least to me, the exclusion principle is not the only way in which something can take up space. Anything that resists compression (has a pressure) could be considered to take up space. I.e. the fact that a gas takes up space has nothing to do with the exclusion principle. In fact it doesn't really matter of you consider a gas of atoms or photons. (TimothyRias (talk) 15:00, 18 May 2009 (UTC))
Hi, sorry to dip in and out in this dippy way; busy lately. I think I was addressing the previous section, above, on overall organization. Not quite sure how it got misplaced, if I did that somehow by accident. Re. your other point, save for the exclusion principle, every other definition boils down to saying the concepts of energy and matter are redundant and identical, since the wave/particle duality is universal, and the uncertainty principle, which does force everything with a position in space to have momentum and thus energy (& so does entail a pressure), the "takes up space" concept only makes sense when one particle excludes another from its place in space. A photon gas can have any number of photons in the same state, and that is not possible for matter without serious violence to the older concepts. Without the exclusion principle, degenerate stars would immediately collapse to black holes, all atoms would shrink to a 1s electronic state, a baseball (or a liter of superfluid 4He) would shrink to atomic size, etc, etc; and matter "as we know it" would really cease to exist in any recognizable sense. The uncertainty principle pressure is essentially different because it does not involve any multi-particle issues or interactions: many particles can occupy the same space. Wwheaton (talk) 14:03, 24 May 2009 (UTC)
First of all, under no definition do the concepts of energy and matter become identical even if you define matter as anything with energy (the GR approach basically), then still matter and energy are fundamentally different concepts. Energy is quantifiable property, it is nothing more than a book keeping tool to keep track of something that is conserved because of the symmetries of spacetime. Matter is not a property, but has properties like mass, energy, volume, charge etc. (Despite all the nonsense written in scifi books something cannot consist of pure energy, that is like saying something consists of pure red)
Second, you somewhat overstate the role of the exclusion principle in the taking up space part of matter. There are many types of matter where the exclusion principle plays no physical role of name. For example in gasses and plasmas at high temperature, there are so many energy quanta to go around, that the probability of two particles ending up in the same state is negligible and the difference between Bose-Einstein statistics, Fermi-Dirac statistics, and Boltzmann statistics completely disappears. The exclusion principle for example does not play that much of role in our Sun. Your baseball would evaporate in a hydrogen like gas if electrons where bosons, in some sense it would take up more space!
But anyway, as interesting as this discussion is, it is getting somewhat off-topic, since it is clear that in some literature the exclusion principle is seem as fundamental for matter. It is definitely part of the reason why some particle physicists do not consider photons to be matter. The article should report this with due weight keeping in mind that there are other definitions. (TimothyRias (talk) 07:59, 25 May 2009 (UTC))
Timothy, Sorry I missed this earlier post as I wrote below. Actually I think we are pretty close to agreement. What would happen to the baseball if there were no exclusion principle (= "XP", ok?) depends on the temperature; if T is high enough, everything evaporates of course. At high enough energy, and low enough density, everything begins to look like free massless particles. But at low enough energy for atoms to exist, without the XP all atoms would look sort of like He, I think, all electrons in the 1s state, getting smaller with increasing Z. (?? I confess I am a little confused about this: the atomic size article shows He measured radius as 0.31 Angstrom, H smaller, only 0.25 A; but calculated sizes 0.31 A for He, 0.51 A for H. I think this may have something to do with the experimental definition of the radius? For everything else, size seems to decrease as Z goes up within a shell, which I take to mean the nuclear-electronic attraction wins out over the electron-electron repulsion.) So at "ordinary" temperatures, I suppose all our normal atoms would collapse to 1s atomic dimensions or less, and bulk matter would all look like more or less dense, liquid, and metallic, with electrons in a gas moving freely around nuclei. Not sure about this, one of our experts must know immediately, but obviously all shell structure and band structure would go away. Not clear solids could exist at all. For more massive objects, like planets, gravity would start to be more and more important I believe. All degenerate objects would collapse to black holes, and I think this would happen for much smaller objects than the normal 1.4 solar mass Chandrasekhar limit for white dwarf stars. As you say, this is interesting but pretty far afield. The behavior of superfluid 4He (bosonic at the high level, but fermionic underneath, and still incompressible, which I do not really understand in detail, but suppose must be due to its ultimately fermion basis) seems more relevant to me. Also that you can make a boson composed of fermions, but not the other way around. So if all matter behaves like 4He in this regard, anything built up out of fermions will resist compression. Again, I would love to hear from someone more knowledgeable than I about this. So I predict that the XP definition will ultimately endure, but for the article, of course I think we should just avoid going into such obscure or exotic places, and only mention that the question remains open. Wwheaton (talk) 21:36, 25 May 2009 (UTC)
Particulate theory of matter as a definition?
The sources cited for using the "particulate theory of matter" as definition for what matter is, do not support this. The source all presuppose that it is known what matter is, and try to explain what it is made of. They actually are a pretty good example of the literature being vague on what matter is. Of course, it is possible analyze their description of what matter is made out of, and infer what they mean by matter. This is what this article is currently doing. It however reeks of WP:SYNTH. It would be much better if we could find a source that does this analysis for use. For the record, I do not oppose this way of defining matter. (it is just one example of the different ways in which 'matter' can be defined.) My problem is with the way it is sourced. (TimothyRias (talk) 08:50, 18 May 2009 (UTC))
Sources
Please identify what statements need better sourcing and why. Vague statements about misuse of sources is not helpful.
The "building block" idea (the idea that matter is made up of "particles") has deep roots, and is used throughout the literature and throughout time: here's one example of a google search. There is no WP:SYNTH going on in the Wiki article.
This basic idea of matter as an assembly of units easily leads to the introduction of alternative "building blocks", and in that way introduces all the possibilities from a unifying thread of presentation. It has much in common with the "scales of definition" approach cited in footnote 6. It also satisfies the criterion of leading from the simple to the more technical. It also satisfies the criterion that the reader is apprised that there is no single definition, but rather, an evolving view of what the "building blocks" are.
It is interesting that some forms of matter (for example, the quark-gluon plasma) qualify as matter using one set of building blocks, but not another, a powerful generalization allowed by the building block idea. In the same way, the building block approach separates "dark matter" from ordinary matter. Brews ohare (talk) 13:40, 20 May 2009 (UTC)
I'm not contesting that there is a long history of trying describe matter in terms of ever more fundamental building blocks. This exactly what many of the sources cited in this article are saying. However, this article is turning the statement "matter is made of building blocks" upside down into "anything made out of the particular building blocks" and also inferring "anything not made out of the said building blocks is not matter". The later two is not what any of the sources in the article are saying. (they merrily try answer the question "what is matter made of?". Such a question supposes a preconception of the notion of matter, it does not however reveal what this preconception is. Of course, it is possible to infer from the answer given, what this preconception was, but that is generally not something that a wikipedia article should be doing.
Let me stress again this article should not be concerned with what any of us think that the definition of matter should be, but on the usage of the term in the scientific (and maybe also the everyday) world. Reliable sources for this would be sources that report on the usage/definition of the term rather than sources that contain the usage. (TimothyRias (talk) 14:37, 20 May 2009 (UTC))
Timothy: Agreed; from the viewpoint of pure logic saying "A is an assembly of B" does not necessarily mean that "Assemblies of B are examples of A". However, I'd suggest that context indicates the whole point of bring up "A is an assembly of B" is to indicate what is taken to be a fundamental aspect of A that has real content. For example, in the historical vein of the 19th century that said "matter is made up of atoms" the sources clearly indicate that this makeup was taken to imply that the properties of atoms were a key to determining the nature of matter. I'd say the people who invoke quarks and leptons as the constituents have exactly the same view: it is not a statement empty of content for the notion of matter. In fact, I believe examples can be found where "assemblies of leptons and quarks" are exactly what the authors consider matter to be, and they expect all its properties in principle can be deduced from this fact. In fact the cited sources are quoted to the effect that this is their definition of matter, as you request.
In any event, this logical nitpicking can be avoided with a bit more pedantic phrasing. It does not require scrapping the whole organization of the article. Brews ohare (talk) 15:25, 20 May 2009 (UTC)
It is not just logical nitpicking. An author discussing quarks and leptons as constituents of matter says nothing about whether the author considers a photon gas to be matter or not. Maybe more importantly it does not say that the author would consider anything made out of quarks and leptons to be matter.
The problem is that the sources (for example the quoted book by 't Hooft) do not make clear what their definition of matter is, but assume that is clear what they mean by matter without giving a definition. This stress my point that we need sources that actual discuss the definition of matter (and preferably how the different definitions relate). (TimothyRias (talk) 15:41, 20 May 2009 (UTC))
The sources are quite clear that photons are not matter. For example: "all the elementary building blocks of matter are fermions" Grotz & Klapdor; "matter is constructed from just four basic entities: up and down quarks, electrons and neutrinos" PCW Davies, "The six leptons and six quarks ... form the basis for all known matter in the universe...These twelve particles represent the basic building blocks for all known matter in the universe; they and their interactions constitute ...the Standard Model of elementary particles." Han. Many more quotes of this ilk are readily found using google. The issue then becomes what exactly is a building block? It may be difficult to find an exact definition of this concept as applied to matter, but I'd say context does show that the whole point of bringing up building blocks as they relate to matter is to specify matter as whatever is made from the building blocks. For example, the entire phase diagram of nuclear matter is constructed using these building blocks with assumed forms for their interactions.
To put the shoe on the other foot, so far as I can find, there exists absolutely no example of an author suggesting that these building blocks can be used to make "something else", something that isn't matter. Can you find an example?
Although not a statement that all constructions from the building blocks are matter, the contrary statement is found: for example, sources that say "dark matter" is not ordinary matter and is not made up of these building blocks.
Returning to context as implying anything made of its building blocks is matter, many authors (e.g. Davies) explain the history of the building block approach and indicate that the historical objective has been to find building blocks to construct matter, not to find building blocks that have multiple purposes and are useful to build 'stuff' other than matter. For example: "[Leucippus and Democritus] argued that the universe consists of nothing but microscopic, indestructible particles moving in a void. The particles don't change: they... maintain a fixed identity forever. But the motion of the particles within the void will bring about the appearance of change. In this scheme, all matter consists of different rearrangements of the particles, and all change is but the rearrangement of particles. The name the philosophers gave their fundamental particles was atomos..." "...The indestructible nature of the atoms was crucial: if the atoms could be pulled apart, then they could change, and the philosophers were back where they started, trying to account for how one thing could turn into another. "(Davies p. 86) Brews ohare (talk) 22:57, 21 May 2009 (UTC)
That is exactly the problem, the historical objective was to find building blocks to construct matter, not to find a definition of matter. Statements like "all matter is made of atoms" were scientific hypotheses about the nature of matter, that could be falsfied by finding matter that is not made of atoms. (at the time it was a logical possibility that matter did not have a smallest building block at all, but was instead continuous for example) Similarly, (at least at a principle level) the statement "anything made of atoms is matter" could befalsified by finding something constructed of atoms that did not fit the bill for matter. (although I'm the first to admit that probably any useful definition of matter would include anything made of atoms.
My point in this is that applying your building blocks definition of matter to the particulate theory of matter, would make the main statement of that theory, 'matter is made out of building blocks' a scientifically void tautology. Hence it is clear that authors discussing this theory are not typically using that definition. The sources currently used to support your claim of a building blocks definition, actually just discuss the idea that matter is made out of building blocks (and what these are). They do not really go into what they consider to be the definition of matter, and are thus unsuitable to support claim that they are supposed to be supporting. (TimothyRias (talk) 09:52, 24 May 2009 (UTC))
Timothy: My perspective on this is somewhat different. The statement "all matter is made of building blocks" is not intended to be directly verifiable. The term "building blocks" is a technical construct, an intermediary concept like "wavefunction". As noted in the article, over time there have been many versions of matter, all compatible with the "building block" idea, but all different because of the choice of building blocks. The testable aspects arise from implementing the chosen selection of building blocks and their interactions, and deducing testable consequences, for example, a phase diagram. I believe this to be the goal of the search for the quark-gluon plasma: it is one facet of an exploration of a phase diagram based upon the building blocks of QCD matter. Brews ohare (talk) 13:32, 24 May 2009 (UTC)
To add: the evolution of the building blocks over time each has encompassed its predecessor, and so engenders the same properties of matter explored in the earlier epoch. However, the evolution of building blocks has followed ever and ever more exotic probes of the properties of matter, and predicted phase diagrams (for example) in regimes not previously accessible in the days of the earlier building blocks. Brews ohare (talk) 13:48, 24 May 2009 (UTC)
"What is matter?" vs. "What is matter made of?"
It is clear that we disagree on this. To me the particulate theory of matter tries to answer the scientific question "what is matter made of?" as a follow up on the question/answer "Q:What are things made of? A:Things are made of matter." So, basically the theory is answering the fundamental question, "what are things made of?". So, clearly I don't agree with you that the particulate theory of matter is defining matter in terms of building blocks. (In fact, I think that for a long time it has been the other way around, the particulate theory of matter defined the building blocks in terms of matter i.e. to Democritus atoms were, by definition, the smallest indivisible parts of matter.) The fact that we disagree on this, alone, stresses the need for sources that do the interpretation for us. There might very well by others that also hold your view, but I don't believe it to be the standard one. (TimothyRias (talk) 08:20, 25 May 2009 (UTC))
Timothy: "What is matter?" "Matter is what is made of leptons and quarks." There may be a reason why most modern authors discuss "What is matter made of?" rather than "What is matter?" It may be that the answer to the first question answers the second one. For example, the answer to the first question also permits calculation of mass and volume, and moreover, suggests that not everything with mass is matter, so defining matter in terms of this property of matter is inadequate. (Those authors that answer the last question "What is matter?" resort to the "Matter is anything that takes up space and has mass" answer, which is fundamentally incorrect). In fact, defining matter in terms of any property of matter has this kind of drawback: some things with the identified property may not be matter and possibly vice versa.
Exactly which properties are definitive? Are there such properties?
The "building block" approach is a more algorithmic idea: just keep hacking away at the smallest building block and see where it takes you. At any stage in the process the properties of matter appropriate at that stage can be deduced, and can be compared with experiment to see if the building blocks explain things observed.
At the present moment, this search is uncovering new forms of matter, produced under extreme conditions. Explanation of the observations requires the concept of quarks, and computes the QCD matter phase diagram. These building blocks do not alter the properties of matter composed of larger-scale building blocks like hadrons, and hadrons do not alter the properties of matter conceived of as made of atoms. The new quark building blocks simply allow discussion of matter under new circumstances. "What is matter?" "Matter is what is made of leptons and quarks." Isn't that definitive until the next building blocks come along?
It is hard for me to imagine the basis for an unchanging and universal definition of matter that could prove resilient enough to cope with an ever more demanding exploration of the ever-evolving properties of matter. The "building block" concept provides a framework for this evolution. Brews ohare (talk) 14:48, 25 May 2009 (UTC)
You seem to be very much stuck on the idea that there is one right definition of matter, with others being wrong. The fact of the matter (forgive the pun) is that there are different definitions in use. Probably everybody agrees that wood is matter, some people (relativists, some cosmologists) would consider a photon gas matter, others (most particle physicists) would not. It think most contemporary physicists would consider dark matter to be 'matter', although it would be by your definition, which is fine. As far as wikipedia is concerned all definitions are equally valid as long as we provide proper sources for their usage. (TimothyRias (talk) 15:14, 25 May 2009 (UTC))
I do not believe that there is one right definition and have continuously suggested the definition evolves with the selection of building block, a moving target. Authors cited in the article state explicitly that photons are not matter. On the other hand, authors are cited to the effect that "dark matter" is not composed of the building blocks of "ordinary matter" requiring a distinction between "ordinary matter" and "dark matter". Brews ohare (talk) 15:19, 25 May 2009 (UTC)
And I contend that whatever definition is preferred, it needs to be generally consistent with the historical usage of the term. A century ago we would have said it was stuff made of "atoms", and noted that there was some evidence that atoms were themselves decomposable into yet more elementary objects, notably electrons and alpha particles. (A few decades earlier we might have worried about the status of "electricity", but then what about "magnetism"?) Then in the 1930s we had electrons, protons, and neutrons, and that was enough for the construction of all the matter known prior to 1900, but had the one dark corner regarding energy due to E = mc2 after 1905, which got more serious in 1915 when stress-energy became the source term for the gravitational field. And then we were struck dumb by the huge plethora of particles and field quanta that appeared after the positron and the mesons. The Standard Model seems to give us hope, with quarks and leptons, but what about photons and gluons? All these particles are supposed to be pointlike (resolutely ignoring string theory for the time being), so they actually don't have volume, yet their quantum states must be extended for them to have finite momentum, energy, and mass. It seems clear that no electrically charged particle can be massless because of the energy associated with the electric field. Yet gluons are massless and carry the color charge. So the strong force field itself cannot involve energy as the EM field does; and if so, all the energy and mass of the nucleons derives from the kinetic energy of their quarks, plus a little bit due to their electric fields. But then there is dark matter, which certainly is a source for G, and thus must have stress-energy, but maybe we don't really know enough to decide if we really ought to call it matter.
My bosom enemies here (who truly do know much more than I do), will notice where I am headed with this. We all agree that any sensible definition of matter must require that it have mass, and thus necessarily energy. I think we agree that non-zero rest mass is not the issue (? do we? We do not actually know of any massless fermions now that neutrinos are known to have mass, right?) But the requirement that it have volume or occupy space (ie, have "place") has two problems. First, it includes everything in physics, so it is arguably too broad. Second, it ignores the obvious (and ancient) distinction between those entities that resist the occupation of their space by others of like kind, and those that are indifferent to this issue. This great divide, between elementary bosons and elementary fermions (that is to say objects that are built up from fermions), is so neat and so clearly important, that I do not see how we can ignore it in this discussion. It is likely to be with us for a long time, I'm guessing even if super-symmetry holds. And it seems to me to be the only possible place to hold onto to prevent us from being forced into saying everything that is, is matter (so we don't get to re-title this article "Everything").
If I can chime in here, I would like to add that the Pauli-exclusion "resistance" of fermions to being smashed into the same space is only important if they aren't charged; if they are charged, the charge is a far more important effect. Furthermore, their wave-nature resistance to being confined is also a far more important "volume-producing" effect. Example: hydrogen is a lot larger than a proton not because of Pauli, but because of de Broglie. And a helium atom is larger than a He+ ion because of the electron repulsion-- no Pauli involved. If electrons were bosons, or the Pauli principle didn't operate, matter would only be an order of magnitude or two denser than it is. All the electrons in every atom would sit in the 1s orbital and that would be that. This would produce very uninteresting chemistry, but otherwise nothing drastic. Consider the fact that superfluid helium II near absolute zero, where all particles are bosons in the ground state, has a density, and it's not a spectacular density, but something not that different from helium I (or for that matter, from liquid helium-3; it's about what 4/3rds of it). So don't blame Pauli, or fermion-repulsion, for much of the gross nature of "matter."
Any by the way, the suggestion that anything that serves as the source term for the gravitational field should be considered "matter" is exactly what I suggested when I suggested we consider matter to be invariant mass. It lets out single photons, but anything else that gravitates, or warps space-time in the normal "pulling" way, is in. As with dark matter, it doesn't have to be hadronic/baryonic. And thus not fermionic, either. Indeed, what do we do if supersymmetry is true, and all that dark matter is the supersymmetric partner of the neutrino, or "sneutrinos"? It would all then be bosonic, and then where would Headbomb be? I think his head would explode. As for dark energy, it gravitates in the opposite way from standard energy, so it can be out of our definition. SBHarris01:57, 26 May 2009 (UTC)
I see way to much "our definition"s, "preferred definition"s, etc. in this discussion. The article should not care what definition any of us prefer. There is plenty of documented evidence that different fields use different definitions, so that is exactly what this article should report. We should also realize that the definition of matter is not the most important part of this article. The knowledge that has been build up over the years on the nature and structure of matter is probably much more important/relevant to potential readers. When at some point in the article forms of matter come that may not be matter to some definitions it can be noted there and then.
By focusing so much on the definition question the article is becoming more technical than it needs to be. In order to be accessible to a broad audience we need to find a way to present to easier stuff first. One way this could be done is by first discussing the structure of matter in a top-down approach (somewhat following the historical path taken by science); So first discuss the larger structures that make up common (to us humans) matter, i.e. atoms and molecules. Then proceed with increasingly smaller (and more technical) structure (nuclei, electrons, protons, neutrons, quarks, etc.), near the end if that it can be noted that there appear to be large amounts of matter that we do not know the structure of (dark matter) May only after that should there come any section discussing the subtleties of different definitions. (which will be much easier to discuss since the article has already introduced different types of matter, hence it is easier to give examples of how the definitions differ. (TimothyRias (talk) 08:40, 26 May 2009 (UTC))
Defining matter in terms of particular properties, such as mass, will immediately put some important literature at variance. On the other hand, defining matter in terms of the intermediary concept of building blocks allows deduction of the properties of matter (mass and volume among others) appropriate to the scale of whatever the chosen building block . It also does allow for different types of matter: ordinary matter and dark matter, for example. It also allows for proceeding from the simpler (older) scales like atoms to the perhaps more complex (modern) scale of quarks and leptons, and allows room for further developments at the sub-quark level. In addition, it follows the historical development of the subject. Brews ohare (talk) 14:37, 26 May 2009 (UTC)
Timothy: Please distinguish between a definition and an algorithm. The present structure of the article is algorithmic: it does not specify any particular definition of matter, nor any definite properties of matter. Like an algorithm, one plugs in one's choice of building block and cranks out the properties of matter appropriate to that choice. Brews ohare (talk) 15:35, 26 May 2009 (UTC)
This article may be more technical than it needs to be
It is time this template was removed. The introduction uses only simple ideas, like "building block". The entire article is qualitative in nature, and technical arguments are avoided by reference to outside sources or are linked to more detailed articles. The introduction of terms like "lepton" and "quark" are merely names (no technical detail assumed or needed), and adequate links are provided for those who want more detail. Brews ohare (talk) 17:55, 26 May 2009 (UTC)
Does anyone object to me setting up automatic archiving for this page using MiszaBot? Unless otherwise agreed, I would set it to archive threads that have been inactive for 30 days.--Oneiros (talk) 13:29, 24 January 2010 (UTC)
No, objection here, although I would set the interval to 100 days. This page is not that active. The interval can always be decreased if it becomes busier. TimothyRias (talk) 16:47, 2 February 2010 (UTC)
I've down graded the article it is C-class. As it stands it is not "essentially complete" as is required for B-class.
To be essentially complete the article should at least contain a history of the concept, after all it is over 2000 years old!
The phases of ordinary matter, basically is one giant digression. This in not an article about phases of matter, that is what the phase (matter) article is for. Having an exhaustive list of phases in this article should simply be auto of the question. (It might be an idea to have a List of matter phases article though.
The current article basically ignores one of the most general definitions of matter: "anything that exists in space", which is very common in the gravity and cosmology.
More specifically cosmologists regard light as a specific case of ultra-relativistic matter, i.e. matter statisfing the "p=ρ/3" equation of state. In general any matter for which the kinetic energy is much larger than it rest mass falls in this category. Neutrinos are another example. TimothyRias (talk) 09:55, 3 February 2010 (UTC)
I've added a section on Historical Origins of matter. This could still use work, especially by incorporating the material from the Toulmin and Goodfield reference, not to mention the McMullin references. In particular it could use a treatment of the evolution of the conception of living matter, as per Toulmin and Goodfield. The article still reads as rather historically myopic, that is, strongly biased to the current physical conception of matter. JKeck (talk) 01:36, 10 March 2010 (UTC)
Nice work! I would try to stay away from phrases like "it is important to..." though. It is generally not the place of Wikipedia to make statements about what is important or not. Doing so, will often lead to problems with NPOV. TimothyRias (talk) 09:16, 10 March 2010 (UTC)
I wonder, if universe is expanding, shouldn't we need more matter for that, is more created as we expand? If not, universe is going to be strecthed thin, right? —Preceding unsigned comment added by Joel-Haglund (talk • contribs) 08:16, 9 February 2010 (UTC)
Is it just me or does the first sentence of this article put you off from reading when you see words like “stuff”, “world”, etc?
“Matter is a general term for the "stuff" of which the world is made.”
Not an entirely ridiculous word choice, “stuff” could however be replaced with material, substance, etc. “World” is very limited. Try universe, existence, etc.
Maybe it should say, “Matter is a general term for the substance or material of which the universe or existence consists.”
"Stuff" while informal is more general than "substance." The latter has a specific technical meaning (see the link to substance theory). "Material," being a near synonym of matter, is what we're trying to define.
"World" is actually more general than universe. World is the narrow, "Sagan" sense means heavenly body, but world in the broader, historical sense means all reality.
At the moment the opening sentence reads, "Matter is a general term for the substance of which physical objects are made." I'm actually okay with it, but I think "substance" needs to go as it doesn't include Aristotelian matter theory, which by the way is still perfectly valid (Descartes didn't disprove it, but rather just hijacked the word). Either that, or you need to say that the present, popular conception of matter is that it is a substance. JKeck (talk) 15:13, 15 March 2010 (UTC)
Assessment comment
The comment(s) below were originally left at Talk:Matter/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
Done 90 days it is.--Oneiros (talk) 19:48, 2 February 2010 (UTC)
