Talk:Particle

Why is there a "health effects" section

Most of the page is about small physics particles which have basically no effect to health. SomeoneCantThinkOfAnything (talk) 15:50, 25 May 2024 (UTC)

No unifying topic

I believe this article should be deleted as not having a good basic topic. Where is there a single book or chapter or paper about this idea of particle? Please supply a source soon or I'll be submitting this for AfD. Dmcq (talk) 17:01, 24 February 2011 (UTC)

This is one of the most important concepts in the history of physical sciences, and in science in general! And you want to delete it??? I've seen a lot of ridiculous ideas, but that's by far the most ridiculous one I've seen on Wikipedia. Headbomb {talk / contribs / physics / books} 17:14, 24 February 2011 (UTC)

Produce a citation which discusses the topic. Dmcq (talk) 22:43, 24 February 2011 (UTC)

In fact I think on the basis of that reply there is a lack of communication and little chance of anything useful so I'll submit it to AfD. Dmcq (talk) 22:48, 24 February 2011 (UTC)

it is not a good imformation — Preceding unsigned comment added by 86.8.234.119 (talk) 19:03, 26 February 2013 (UTC)

Revert

Moved from User talk:Headbomb

In this revert you removed some tags that indicate a number of the things written are unsourced.

In this revert you removed some tags that indicate a number of the things written are unsourced.

Additionally, you may wish to research smooth particle hydrodynamics. The justification for particle number has nothing to do with the scale of stars compared to galaxies. The smallest dwarf galaxies have a very small number of stars and therefore the statement that you can consider a star to be a particle compared to the size of the galaxy alone is a wild overgeneralization.

IvoryMeerkat (talk) 18:08, 24 February 2011 (UTC)

It is not. Stars can be considered particles whenever the dimensions of a star is negligible compared to the whole. The number of stars is completely irrelevant. Headbomb {talk / contribs / physics / books} 18:15, 24 February 2011 (UTC)

So, since some galaxies exist where the dimensions of a star are not negligible compared to the whole (e.g. the first galaxies with Pop III stars) then the statement in the article is wrong. IvoryMeerkat (talk) 18:32, 24 February 2011 (UTC)

At worse the statement doesn't apply to a very very very small subset of galaxies at a very specific moment in time, and the article doesn't suggest that stars can always be considered particles, regardless of context. Most galaxies, even the small ones, are several thousands light-years wide. The largest of stars (VY Canis Majoris for example) are a few thousands solar radii wide a most. That's roughly 8 orders of magnitudes appart. Headbomb {talk / contribs / physics / books} 18:48, 24 February 2011 (UTC)

The cite you're using, however, is also not really good. SPH doesn't necessarily correspond to stars but more often to packets of gas. More than this, the discussion of stars acting as "particles" is normally attributed in astrophysics literature to the earliest discussion of galactic dynamics (e.g. Binney & Tremaine) where stars are treated as test particles in the potential regardless of whether they are actually that way or not. The problem is that the statements don't really capture the nuance and depth of what we mean when we treat a "star" as a "particle". It's an approximation that is due to observational convenience mostly and happens to be a good approximation when you look at the limiting regimes. In other words, the text is putting the cart before the horse. IvoryMeerkat (talk) 18:58, 24 February 2011 (UTC)

A better reference could probably be found for that, I just gave it as an example. However, modeling galaxies as being made of particles (aka stars) is hardly putting the horse before the cart. You can even model the universe as being made of particles (galaxy clusters!), and this is indeed done routinely. Headbomb {talk / contribs / physics / books} 19:04, 24 February 2011 (UTC)

But no one models galaxies as being made of particles (aka stars). People start with a particle size that is usually set by the limitations of the computation itself. IvoryMeerkat (talk) 19:12, 24 February 2011 (UTC)

It's done all the time! Haven't you heard of N-body simulations before? Headbomb {talk / contribs / physics / books} 19:17, 24 February 2011 (UTC)

IM is correct, last I checked. The bodies being simulated aren't stars - they're tracer points representing some fraction of the matter in the galaxy (normal or dark, usually tracked separately). You can certainly argue from first principles that stars are essentially particles in gravitational simulations (ditto planets), and I agree with that conclusion, but per WP:VNT, the article should focus on uses of the term "particle" that appear widely in literature. --Christopher Thomas (talk) 19:22, 24 February 2011 (UTC)

Well the term is found in literature. I gave a specific citation for that [1] "Galaxies are modelled as a collection of gravitating particles that represent the stars and the mysterious dark matter.", but this is referencing the obvious at this point. Headbomb {talk / contribs / physics / books} 19:54, 24 February 2011 (UTC)

Dark matter particles are not stars. IvoryMeerkat (talk) 20:19, 24 February 2011 (UTC)

Per my initial comment, the "gravitating particles" do not correspond to individual physical objects within the galaxies being simulated. They represent some set fraction of the mass of that galaxy, and nothing more. Read the page you linked: collisions between the Milky Way and Andromeda galaxies was simulated by models containing hundreds of millions of particles, but the galaxies themselves contain hundreds of billions of stars (Milky Way) or more (Andromeda Galaxy). --Christopher Thomas (talk) 23:13, 24 February 2011 (UTC)

Who said there was, or needs to be, a one to one correspondance? Headbomb {talk / contribs / physics / books} 03:20, 25 February 2011 (UTC)

You did, earlier in this thread, when using that simulation as a citation backing up a "stars can be considered particles" statement. I agree that they can be, and I agree that in some n-body simulations, they are. However, you seem to be a bit hasty in your choice of references, and I think you've been more than a bit hasty when dismissing the various objections that have been raised in this thread and elsewhere.

That said, this passed my "I'd rather be doing something productive" threshold several hours ago. All I can ask is that you at least consider some of the comments made by myself and others regarding your decision to create this page, as opposed to improving existing pages on this topic. --Christopher Thomas (talk) 05:21, 25 February 2011 (UTC)

Dont' know if you noticed, but there's a deletion discussion going on. If I'm hasty, it's because I don't have the luxury of time. Headbomb {talk / contribs / physics / books} 06:48, 25 February 2011 (UTC)

Deletion discussions stay open for a week before being closed. You have plenty of time; relax. If criticisms in the deletion discussion are sufficiently heavy that it looks like it would be deleted, even then there's no rush, as you can copy it to userspace, take your time bringing it to a state where you feel it would answer any reasonable criticism, and then convince people at WT:PHYS or elsewhere that the page should be reinstated.

The whole reason there's a deletion discussion at all is that the "convince people" stage wasn't fully completed. Enthusiasm is laudable, and you've made very valuable contributions across the board, but every so often there will still be situations where it's worth reconsidering your position. Goodness knows it's happened to me often enough (this AfD is arguably one such case, as it looks like I'm in the minority). --Christopher Thomas (talk) 07:30, 25 February 2011 (UTC)

Truly punctual

elementary particles are truly punctual

The above sentence appears in the Composition section with punctual pipe-linked to Point particle. I disagree with this summary of the cited source ([2]). To me the words "truly punctual" imply an infinitessimal point but that is not what the source claims. Point particle states it is an idealized concept. I think it needs a rewrite. I am no expert, but I'll start with "are closer to idealized points". Unless there are sources that show electrons have a cross-section of exactly zero - all I have found is that its size is small but still unknown. I was also under the impression that linear extent became meaningless below are certain scale. -84user (talk) 00:20, 25 February 2011 (UTC)

Particulates

The uses of Particulate, Particulates, Particulate matter is under discussion, see talk:Particulates -- 65.94.169.222 (talk) 04:35, 4 August 2014 (UTC)

Addition by IP

An IP added the following to the stability section

Particles can be either on-mass-shell, then called "real," or off-mass-shell, then called "virtual" and considered present only for very short times, within the constraint of energy-time uncertainty relations.

I removed it from that section, as it's not related to stability. But maybe there's a place for it elsewhere. Headbomb {t · c · p · b} 23:36, 20 May 2021 (UTC)

Proposed merge of Massive particle into Particle

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

---

The concept of "massive particle" has no meaning other than a particle with mass. The modifier "massive" is used in discussions of "particles" and explaining "massive particle" is clearest in the full context of Particle. Conversely the massive/massless issue needs to be covered in the "particle" article. Johnjbarton (talk) 16:53, 17 November 2025 (UTC)

Well, I don't quite agree. The same thing could be said for massless particle. Currently the article clearly isn't very good. Yes, a massive particle is a particle with mass. And a massless particle is a particle without mass. But what these articles should focus on is the features and properties of such particles. Off the top of my head example this article can cover the following:

• Discuss properties of massive particles, their dynamics, etc.
• Discuss various types of massive particles (I guess that'll mainly deal with representation theory, Wigner's classification, etc).
• Discuss various mass generation mechanisms.
• Discuss the massive particles within the SM.
• Definitely there is more than this.

The massless article page similarly needs a spruce up. I definitely think there is enough here to get these to be full articles in their own right. For the massless particle page at least the page views definitely seem to be calling for an imporvement on that page. And I don't think one should have a massless particle page without a corresponding massive particle page.

Additionally merging this in the particle page has the disadvantage of burying the particle physics nature of massive particle/massless particle into a discussion on the more generic (generally point) particle concept in physics. OpenScience709 (talk) 11:59, 18 November 2025 (UTC)

I challenge you to find a source that find significant coverage of the top "massive particle" as such. Your outline above presupposes an article on the topic "massive particle" with information "massive particle properties". I've never seen such a presentation. Rather, what I see are sources on particles or representation theory or mass generation, etc. Thus the encyclopedia should discuss "massive particle" in those places. I'm not claiming that "massive particle" is not used but rather that we should not invert the order of concepts we see in sources. Johnjbarton (talk) 16:18, 18 November 2025 (UTC)

Again, I don't feel too strongly about this topic. And I agree that you generally won't find articles, books, or chapters specifically just discussing "massive particle" as their sole focus.

Although as far as I see it, thats not what the notability criteria for Wikipedia are. A topic has to have significant coverage in the literature to be notable. Whether this coverage is usually within the context of something else or not is not mentioned in the guidelines. More importantly, there are numerous Wikipedia articles on topics that are widely used in the literature, but are not usually discussed in and of themselves. Say Feynman slash notation, correlation function (quantum field theory), On shell and off shell, Metric signature, etc. You won't find many (or sometimes any) chapters/articles explicitly dedicated to these topics, yet I would definitely say they are notable.

Same goes for massive and massless particles. They are things widely discussed in the literautre, but generally always in the context of something else.

Although I can see that massive particle may be less notable. But I do have to disagree (ik youre not arguing it currently(?)) with arguing the same thing for massless particle which I do think is explicitly notable. They have properties that are explicitly discussed in standard textbooks. Plenty of representation theory discussions on it, say chapter 10 "Massless Particles" in Theory and Applications of the Poincaré Group by Baskal et al. But other things too, say Schwartz (Chapter 8) on gauge invariance of massless spin 1 particles, on soft theorems, or Srednicki's chapter 50 ("Massless particles and spinor helicity") on it the spinor helicity formalism for massless particles. OpenScience709 (talk) 18:38, 19 November 2025 (UTC)

But basically I'm not too fussed about merging massive article into particle. Against doing the same for massless particle. OpenScience709 (talk) 18:39, 19 November 2025 (UTC)

Merge Massive particle and also Massless particle – The first is very short and the second is very poorly sourced, no WP:N in sight. FaviFake (talk) 16:38, 18 November 2025 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

@User:Johnjbarton are you still interested in performing the merge? Let me know if you need any help! ScrubbedFalcon (talk) 16:37, 6 March 2026 (UTC)

Template:Merge done: If someone wants to start a new discussion about massless particle they can. ScrubbedFalcon (talk) 23:03, 8 March 2026 (UTC)

Contested close

Moved from User talk:Headbomb. Headbomb {t · c · p · b} 18:21, 8 March 2026 (UTC)

Hi! I just noticed that you reverted the close I performed on the discussion to merge massless particle into particle a few days ago. I have to say that I don't appreciate you reverting the close without contacting me at all. Per WP:CLOSECHALLENGE there are clear processes for contesting a close, even of a relatively informal discussion like a merge. I also noticed that you reverted @FaviFake's edit that restored the initial close where they also mentioned in the edit summary that there are processes in place to contest a close. I can't find any evidence that you contacted them about that revert either. I've restored my initial close again and would appreciate it if you would discuss this with me before editing the close again. ScrubbedFalcon (talk) 18:14, 8 March 2026 (UTC)

1) You're not an admin 2) What you bodly closed can be boldy re-closed. 3) More susbtantially the article proposed being merge is substantially different from what it was at any point during the discussion. That voids all virtually arguments made in the discussion, especially given that the newly added material to massive particle was explicitely objected to being merged into particle. There is zero consensus to add uberspecialist concepts like Weyl fermions to a broad concept article like particle. Headbomb {t · c · p · b} 18:17, 8 March 2026 (UTC)

1. Per WP:Closing discussions any uninvolved editor may close most discussions, not just admins. And regarding challenges to closes it says that "Closures will rarely be changed by either the closing editor or a closure review if the complaint is that the closer is not an admin."
2. I wouldn't say it was a bold closure, I was just closing the discussion. And again, I don't appreciate you reverting the close without contacting me at all.
3. Your objection seems to be about the merger of content from the massless particle article. The consensus I found was about merging massive particle to particle, I noted separately in the summary that a suggestion had been made about massless particles and said explicitly that consensus for that merge wasn't clear. It seems like you want to object to the close based on that note. ScrubbedFalcon (talk) 18:42, 8 March 2026 (UTC)

I'm surprised to see such an experienced user not even know the basics of how formal discussions work on WP. Scrubbed is completely right here: "bold closures" aren't a thing, it's extremely rare to see merge proposals closed by admins, and there are processes in place for contesting closures.

I'm also surprised that the only thing that wasn't reverted was my bold merger. Of course I'll revert it, since it appears, as Scrubbed says, that that's what you're actually opposed to. But please do read a few times the procedures for closures! FaviFake (talk) 22:12, 8 March 2026 (UTC)

Massless particle should be merged here to massive particle. That's fine. What shouldn't be merged is the new article to particle. Headbomb {t · c · p · b} 00:08, 9 March 2026 (UTC)

Alright then, i've merged Massless particle again. To contest the closure of the discussion regarding massIVE particles, please follow the standard procedure. FaviFake (talk) 19:50, 9 March 2026 (UTC)

Reverted, again. There is zero consensus for such a merge. Headbomb {t · c · p · b} 20:19, 9 March 2026 (UTC)

Massive/massless arc welding particles? Not.

Mea culpa. I came upon "massive particle" which is a term used in particle physics in opposition to "massless particle". I jumped to the conclusion that Particle would describe the unmodified noun, and thus be the natural home for massive/massless content. I proposed a merge which was accepted.

Now I see that Particle is a WP:Broad concept. Only the particle physics "particle" has a massless form and thus "massive particle" only makes sense in the context of particle physics.

I guess I will try to fix this up by adding content to this article on the important special subtopic, "particles in particle physics". Johnjbarton (talk) 00:23, 9 March 2026 (UTC)

How is particle different from point particle?

Ok I can't figure out what this article is about. We have point particle which is what I find in classical mechanics sources, so it is evidently not that. The sources here are all over the map:

• AMS Glossary: An aggregation of sufficiently many atoms or molecules that it can be assigned macroscopic properties such as volume, density, pressure, and temperature. But sometimes by particle, without qualification, is meant a subatomic particle such as the proton or neutron (which themselves are composed of other “elementary particles”) or the electron.
• OED: irrelevant
• Soil mechanics:?
• Sears & Zemansky: basically a point particle. They define it a bodies without rotation. But then we can't have composite particles, or soil for that matter.

Should this be WP:Broad concept article? Johnjbarton (talk) 02:21, 9 March 2026 (UTC)

A chunk of metal can be treated as a particle. A chunk of metal is evidentally not truly punctual, even if it can be treated for many purposes as point-like. Headbomb {t · c · p · b} 03:27, 9 March 2026 (UTC)

I don't understand how your comment is related to my question. I understand the concepts. My question is what concept is this article reporting on?

However, perhaps my question answered itself: the contradictions in the sources are a message. I plan to change the article to explicitly cover all concepts "particle", in size order. Maybe starting with galaxies just for fun. Johnjbarton (talk) 14:46, 9 March 2026 (UTC)

Yeah it does sound like this article needs someone to be bold and take the reigns. Are these the same issues that led to it to being brought to AfD in § No unifying topic? FaviFake (talk) 19:53, 9 March 2026 (UTC)

"My question is what concept is this article reporting on?" The very general concept of particle, i.e. small localized objects in a larger context. From shrapnel, to dust, to powders, to molecules, atoms and subatomics particles (as well as larger particles, like people in a crowd, stars in a galaxy etc...). Basically what you tell a K-12 kid that a particle is when they encounter the particle theory of matter. Or whatever you mean when you say silt has a particle size of roughly 5-60 μm. Headbomb {t · c · p · b} 19:58, 9 March 2026 (UTC)

Merge proposal for Massless particle

To quote Headbomb, I think Massless particle should be merged here. It was already proposed for merging in § Proposed merge of Massive particle into Particle but wasn't properly discussed. To me it seems a small subtopic of particle that relies heavily the context in this page. FaviFake (talk) 20:50, 9 March 2026 (UTC)

Merge selectively and link to the more specialist topics on their own pages. I think the updated article is looking good thanks in no small part to Johnjbarton, merging massless particle to a sub section under particle physics/mass makes sense to me as a way to provide a good introduction and links to more in-depth articles. Support for editorial reasons (kind of PAGEDECIDE) ScrubbedFalcon (talk) 21:11, 9 March 2026 (UTC)

Oppose I think that massless particle will unbalance this article. To succeed as a broad topic, the various summaries need to similar in size and scope. Particle#Mass should be a short summary. As far as I know, massive/massless particles only come up in the context of relativity. Yes, mass or no mass is discussed for all kinds of particle physics models but the specific distinction arose in relativity AFAIK. Other candidates: Mass in special relativity, Invariant mass, Mass, Particle physics. I lean towards "particle physics" because it has other classification discussion. Johnjbarton (talk) 22:12, 9 March 2026 (UTC)

Thanks. Would you support a merger to Particle physics? I've added the tag to it. FaviFake (talk) 11:33, 10 March 2026 (UTC)

Oppose this is a general overview of the basic properties of particles broadly speaking. Stuff about Weyl fermions and quasiparticles do not belong here. Headbomb {t · c · p · b} 22:52, 9 March 2026 (UTC)

Oppose See my reasons outlined in the massive particle discussion. OpenScience709 (talk) 13:51, 12 March 2026 (UTC)

What is an elementary particle

In this article

• Weinberg, Steven (1997). "What is an elementary particle?". Beam Line. Vol. 27, no. 1. Stanford Linear Accelerator.

Steven Weinberg makes the point that "elementary particle" is not an empirical finding but a construct or convention of theory. He starts out with “What is an elementary particle?” I would have to admit that no one really knows. and he should know.

To me this is a much better source than what we have now:

• D'Souza, I. A.; Kalman, C. S. (1992). Preons: Models of Leptons, Quarks and Gauge Bosons as Composite Objects. World Scientific. ISBN 978-981-02-1019-9.

However @Headbomb however seems to disagree.

I agree that the content I used should have appeared before the SM sentence. And we could change it to eg "The concept of an elementary particle is not based on measurements but instead depends on a theoretical framework." then go on with the SM bit. Johnjbarton (talk) 00:46, 11 March 2026 (UTC)

Just to clarify: my problems with "However it is possible that some of these might be composite particles after all, and merely appear to be elementary to scientists now." are: "preon" is hidden, the concept is dated, and the slippery nature of 'elementary particle' is omitted. The core issue is not "composite particle after all" but rather that elementary/composite is not empirically testable. Johnjbarton (talk) 01:04, 11 March 2026 (UTC)

I'm not locked on keeping D'Souza, but it fairly comprehensively reviews theories where quarks turn out to be composite (which are generally known as preons, regardless of the specific type of model involved), so I don't see what is gained by removed that source. Were I disagree is the emphasis on the general faffing about related to the pre-quark model understanding of the particle zoo of the 1950s-1970s. While yes, which particle are considered elementary are to some extent model dependant, the current best model we have is the Standard Model and which particle are considered elementary in the SM is not ambiguous in the least.

It comes down to the intended readership of this article. IMO, it should be generally aimed so that someone in, let's say 9th grade chemistry, can follow the vast majority of it. The specific details of which and how things are determined to be elementary or not can be left to elementary particle. Headbomb {t · c · p · b} 01:05, 11 March 2026 (UTC)

Or to summarize we should stick fairly close to KISS here. "Some particles are composite, some are elementary, this is the current state of things, but it's always possible what particles with think are elementary ultimately turn out to be composite." Headbomb {t · c · p · b} 01:18, 11 March 2026 (UTC)

I agree with your final point. I think we should change this "particle physics" section altogether to be more concisely a SM summary. As it is the content is left from former versions. Johnjbarton (talk) 01:22, 11 March 2026 (UTC)