Talk:Planck length/Archive 2

Latest comment: 2 years ago by 178.120.49.111 in topic Theoretical significance
Archive 1 Archive 2 Archive 3

Reference frames and black hole information

I have two problems with the explanation given in this article. First, doesn't the issue of whether something is less than the Planck length depend on the reference frame? Suppose there is a ship traveling at .9c relative to me, and they are trying to measure a distance that, to them, is 1.2 Planck lengths. Wouldn't I measure it to be less than a Planck length?

Also, how would being absorbed by a black hole mean that the photon can't give information about the particle's position? Wouldn't the black hole carry information from the photon, such as mass and momentum?Flarity 21:27, 28 October 2006 (UTC)

What is it the length of?

Most lengths are defined as the length of some physical item. I see that the Planck length is 10^-20 x the diameter of a proton... but why? I do understand that the length falls out of other constants, it doesn't lead to the other constants, but not how the length was defined to be what it is.Garrie 05:05, 30 August 2007 (UTC)

It's not the length of anything in particular. In any theory that has G, h and c as constants, the Planck length, or small multiples of it, is likely to turn up just because of dimensional analysis — it's the only way to get a length from those constants. There's no reason to believe that it's a quantum of length or a minimum meaningful distance or anything like that, unless some theory of quantum gravity predicts that it is. There's actually some reason to believe that area is more fundamental than length — Loop quantum gravity has a quantum of area, the string theory Lagrangian is proportional to the surface area of the world sheet, and the Bekenstein entropy bound is roughly one bit per Planck area. -- BenRG 21:13, 30 August 2007 (UTC)
So "It is the scale at which classical ideas about gravity and space-time cease to be valid, and quantum effects dominate" is nonsense. Quantum effects dominate at much higher scales. --Rumping 00:04, 11 September 2007 (UTC)
That's talking about quantum effects on spacetime specifically. But, yeah, it's nonsense to claim that spacetime is dominated by quantum effects at the Planck length when the truth is that nobody has the faintest idea what happens at the Planck length. I rewrote that paragraph. -- BenRG 14:41, 11 September 2007 (UTC)

Imperial values in info box

Is there some reason why these figures are not in normalised standard form? CrispMuncher (talk) 14:45, 3 February 2009 (UTC)

I've just noticed that the same holds for the SI figures as well. Since I can't see any rational reason for this I'm going to go ahead and change them now. CrispMuncher (talk) 17:28, 4 February 2009 (UTC)
I see the problem now. It is the defined behaviour of the units of length template to use engineering steps. This seems strange especially for the imperial values, and arguably it is not relevant here since the unit is not really used in practical applications. However, I won't touch it for now without any comments. I am tempted to subst in the template and manually edit it but won't do that for now. CrispMuncher (talk) 17:36, 4 February 2009 (UTC)

Within the info box "Natural units" has the value 11.706 /s. Isn't this the sqrt of the inverse of the fine structure constant? How do you get that number from the Planck length? 65.8.183.172 (talk) 01:54, 26 February 2009 (UTC) Krakers 20:53, 25 February 2009.

Quantum effects

I'm casually curious about what "quantum effects" are, but the term redirects me to "quantum Hall effect", which doesn't help. Unfree (talk) 20:10, 19 October 2009 (UTC)

Odd sentence in the history section

The last sentence of the history section reads "Note that at such a distance scale, the uncertainty principle materially impairs the ability to make any useful statements about what is actually happening." What is this supposed to mean? Could someone either explain its meaning and perhaps also its relevance to a section ostensibly about history or delete it? --Vaughan Pratt (talk) 05:21, 2 November 2009 (UTC)

Deleted (along with the rest of the section). -- BenRG (talk) 14:17, 2 November 2009 (UTC)

True Meaning

Just to clarify, is the article saying that anything that can possibly be noticeable length wise must be at least a size equal or greater than the Planck length or it can't be observed? And if this is what it is saying, does that mean that with the advance of technology there could at some point be a way to observe something smaller than Planck length, or that it will always be impossible to observe such a thing? Livingston 16:14, 22 July 2009 (UTC)

What it's saying is that anything with a wavelength short enough to be smaller than the Planck length would have enough energy to have an event horizon larger than the Planck length (it would end up being a miniature black hole). So, the Planck length is the smallest length that anything can have (either its wavelength or its event horizon size is forced to be equal to or larger than this length). --Christopher Thomas (talk) 19:49, 22 July 2009 (UTC)::
That doesn't prove that nothing in existance can be smaller than planck length, it just states that it's mathematically inconvenient to consider such things. Who's to say that these ultra small wavelengths can't exist, and that they don't cause miniature black holes all around us? Obviously there are units smaller than Planck length, otherwise what is planck length "made of" (for lack of a better term)? Is it completely in and of itself? That seems teleological to me.
Planck length represents the quanta of space, as do Planck time for time. See, space-time is discrete (like any virtual reality system) and not a smooth continuum as some believe. Unfortunately, many great physicists got/get stuck here. 80.237.46.214 (talk) 22:56, 26 April 2010 (UTC)
(adjusted indentation above). Isn't it the original/actual size of the universe? 72.228.177.92 (talk) 07:19, 12 September 2010 (UTC)

Significance of the Planck Length / Rest mass / Gravitational field energy

Fr = mc² / αx²


Fr = force times distance = energy ≈ energy in the gravitational field of a particle between infinity and its bohr radius. Escape_velocity#Calculating_an_escape_velocity)
F = Gm²/r² = force due to gravity between 2 particles of mass m at a distance of r
r = Bohr radius for a particle of mass m (orbiting a nucleus of infinite mass and charge = 1)


mc² = energy in the rest mass of a particle
m = mass of particle
c = speed of light


αx² = ratio of energy in rest mass to energy in gravitational field above the Bohr radius
α = (dimensionless) Fine-structure constant = 1/137.035999 = 0.0072973525 = e²/4πεℏc
x = r/Lp = (dimensionless) number of Planck lengths in the Bohr radius of a particle with mass m
r = Bohr radius of particle of mass m = (m/mₑ) * 5.2917720859 × 10−11 meters = (m/mₑ) * 0.529 Angstroms
mₑ = mass of electron = 9.109 × 10−31 kg
Lp = Planck length = √(ℏG/c³) = √(mαcrG/c³) = √(mαcrFr²/c³m²) = 1.616252 × 10−35 meters
= mvr = mαcr = angular momentum of particle in ground state of bohr atom
G = Gravitational_constant = Fr² / m²


particle with a Bohr radius of 1 Planck length

m = xₑMe = 0.298 grams = 13,692 Planck masses.
xₑ = 3.274 × 1026 = number of Planck lengths in the Bohr radius of an electron
Me = mass of electron
Planck mass = 2.17644×10−8 kg
αx² = α
Amazingly, at this size, the energy in the gravitational field is 137 (1/α) times the energy in the rest mass.
Such an intense gravitational field would exhibit significant Gravitomagnetic effects.
Its Schwarzschild radius is 2Gm/c² = m * 1.48 × 10−27 meters/kg = 4.41 × 10-31 meters = 27,313 planck lengths


Bohr model

mv²/r = e²/4πεr² (Bohr_model#Electron_energy_levels)
mv²/r = mr(v/r)² = Centrifugal force
e²/4πεr² = Electrostatic force between 2 equal charges at a distance of r
mvr = mαcr = = h/2π = e²/4πεαc = angular momentum of particle in ground state of Bohr atom
v² = α²c² = e²/4πεrm = e²v/4πεℏ
r = ℏ/mv = 4πεℏ²/e²m
v = αc = e²/4πεℏ = velocity of particle in ground state of Bohr model (of atom with nucleus of infinite mass and charge = 1)
v is independent of the mass of the particle
Bohr magneton = μB = ℏγ = ℏe/2m = Spin magnetic moment of electron (See Gyromagnetic_ratio)


Other radii

Reduced_Compton_wavelength (of particle of mass m) = λ/2π = ℏ/mc = rα
λ = Compton wavelength
Classical electron radius = rα²
Van der Waals radius of hydrogen = 1.2 Angstroms = 2.268r


Sphere

Volume of Sphere = (4/3)πr³
Surface area of Sphere = 4πr²
Angular momentum of Sphere = (2/5)mvr = (2/5)mr²(v/r) = I(v/r) (See List of moments of inertia)
radius of sphere with angular momentum ℏ and angular velocity 2πcR = √(5)r = 2.236r
2πcR = Rydberg Angular frequency = 2πmα²c²/4πℏ = 2πmα²c²/4πmαcr = αc/2rb
cR = Rydberg frequency = Rf = mα²c²/4πℏ
Net outward force acting on all parts of a rotating sphere = (2/3)mr(v/r)² = (2/3)mv²/r
Centripetal force = mr(v/r)² = mv²/r
Net inward force acting on all parts of a charged sphere due to an equal and opposite central charge = 3(q²/4πεr²)
q²/4πεr² = Electrostatic force between 2 charged particles at a distance of r

Just granpa (talk) 12:18, 20 November 2010 (UTC)

Plain Language

Can this article get a section where less technical language is used? --JSleeper (talk) 02:14, 7 July 2010 (UTC)

I have tagged it as too technical, and hopefully somebody who understands the article can (at the very least) make a non-technical opening paragraph. Crisco 1492 (talk) 02:07, 8 January 2011 (UTC)

Additions of 18 Feb 2011

This strikes me as a lot of unsourced pseudoscience. Certainly isn't well written and may be factually inaccurate. I am new to making large changes like this, but I really think the longer it stays up the more likely it is to perpetuate misinformation. Ashaver (talk) 20:28, 19 March 2011 (UTC)

Visualization

I was surprised not to find the following (rough) visualization of the scale. Keeping in mind that arithmetic is not original research (e.g. dividing the radius of the sun by that of the earth and saying the former is "roughly 110 times bigger" or "about 100 times bigger" is arithmetic - not original research) here is the visualization that is a remarkable coincidence and allows us mere human beings to visualize, roughly, the Planck scale.

1) Per the article, the Observable_universe has a diameter of some 91.4 billion light years which in meters is

8.64692296 × 10^26 meters

or roughly 10^27 meters.

The smallest thing the human eye can see (for this, one can find references) is about 1/10 of a millimeter, or 10^(-4) meters (excellent eyes can have a "resolution" of 0.04mm, or 2.5 times smaller, per ScienceFocus.come - but that's for the best eyes, Naked_eye gives " 0.1 to 0.3 mm" and perhaps 0.05 seeable - either away, to within 1 (or even half) of an order of magnitude, it's 10^(-4)meters

Ratio is about 10^27/10^(-4) or 10^31

2) Now Planck length is given in our article as 1.616199(97)×10^(−35) again less than a half an order of magnitude away from, more simply, 10^(-35)

The ratio from a 0.1mm particle to this is, coincidentally, none other than: (10^(-4)) / (10^(-35)) which is again 10^31

Disclaimer: I'm *not* suggesting we put all this arithmetic in the article..this is just the background.

But this little arithmetic calculation means we can state:

"If a particle about 0.1mm in size, roughly the smallest the human eye can see, were magnified in size to be as large as the observable universe, then inside that universe, the Planck length would be roughly the size of the smallest object the naked human eye can see" (is accurate to within (actually significantly less than) an order of magnitude) and we can add the clarifier, "in other words, the diameter of the observable universe is to within less than an order of magnitude, larger than a 0.1 millimeter object, roughly at or near the limits of the unaided human eye, by about the same factor as that 0.1mm object is larger than the Planck length" Harel (talk) 03:09, 9 July 2013 (UTC)

One can add, a little less precise but still fairly accurately, that since the ratio of the diameter of the observable universe to the radius of the Milky Way galaxy is close to 10^6 (the former a bit under 100 billion LY, the latter a bit more than 100 thousand LY) and since the diameter of a Hydrogen_atom is given as 1.1 angstroms or very close to 1 angstrom 910^(-10) meters which is 10^6 times smaller than that 0.1mm sized dot in question, we can expand this visualization to say that:
If the diameter of the observable universe is representing that barely-visible 0.1 millimeter dot or particle, then our Milky Way galaxy by its diameter would represent a Hydrogen atom, and the Planck length would in this "universe" be represented by an actual 0.1mm dot" ; or the three part proportion
(Observable universe diameter) : (Milky Way diameter) : (0.1 mm barely visible dot)
representing (better than up to an order of magnitude, fairly good approximation actually) the three part proportion:
(that same barely visible with naked eye, 0.1mm dot) : (diameter of Hydrogen atom) : (the Planck length)
(I may be away from internet access for a couple of days so may only try to add later, but will check back later) Cheers, Harel (talk) 00:36, 10 July 2013 (UTC)

A different kind of ultimate limit (7/2012)

In my humble opinion, the current design of the page says more about Wikipedia guidelines than it does about the Planck length. The page now essentially contains an equation and an annotated bibliography. The history of the page is sort of a "flight to safety": in the relentless pursuit of committee-enforced verifiability, all attempts at interpretation - or even justification of the definition - have been sacrificed. The result is nice and safe, and meets the Wikipedia guidelines. But the result is uninteresting to experts and not very useful for non-experts. — Preceding unsigned comment added by 76.115.88.202 (talk) 23:49, 6 July 2012 (UTC)

I have changed the section from "Physical significance" to "Theoretical significance". It seems that you think even "significance" is too much, feel free to edit.
The lead section is the most problematic, the lack of physical application means that its quantity is not important. The lead should express its theoretical definition and meaning first. For instance, the smallest measurable length and the shortest length are very different, the former is a technical result from QM, it is technical that the word "measurable" differs from the common interpretation, the latter is a philosophical ideal, probably what we mean by unit or infinitesimal. Planck length also serves as an argument for ultrafinitism and "computable universe" for the claim that the universe is discrete. AFAIK, Planck length is a theoretical length that we fail to measure length beyond this length. It gives no answer on the ultimate nature of space or universe. --14.198.220.253 (talk) 10:24, 9 November 2013 (UTC)

Too Technical

Although it is mentioned above that a Planck length is roughly the size of a flea's egg, there is nothing in the article itself that is clear enough for a general reader to understand the Planck length as more than just a really small measurement. Hence why it is tagged as too technical. Crisco 1492 (talk) 12:24, 7 January 2011 (UTC) Hi, I came to Planck length for a link marked Planck volume on a page giving orders of magnitude of volume. Without getting too technical, I am not seeing anything obvious here about a Planck volume. In the commonsense world, a volume is just a length cubed. Is that the case here? Is a Planck volume just a Planck length cubed? I could imagine (just as speculation) all sorts of possibilities for knowing a volume more precisely than a length, but only in. 2 of the 3 (or more;) dimensions. A non-technical introduction would be useful. And maybe Planck Volume should be on a page of its own. 212.183.128.114 (talk) 14:28, 11 June 2012 (UTC) G1CMZ And that bit about being the size of a fleas egg sounds so wrong. A fleas egg.presumably has structure (little fleas, food, if its at all like a ,chicken). But there is no room for such structure inside of a Planck length. 212.183.128.114 (talk) 14:39, 11 June 2012 (UTC) G1CMZ

It is a technical topic and there is little point to make it looks non-technical. Consider the fact that one has to "bootstrap" their knowledge on QM first to properly understand what it means, put that into account. --14.198.220.253 (talk) 10:33, 9 November 2013 (UTC)

Use of "the" before "Planck length"

There appears to be some disagreement over whether the phrase "Planck length" should always be given the article "the", or whether the article can be left out in some cases. Looking over various web pages that mention the phrase, it appears the use of "the" is pretty close to universal.

  1. http://math.ucr.edu/home/baez/planck/node2.html -- all (7) uses include "the"
  2. http://abyss.uoregon.edu/~js/glossary/planck_time.html -- two uses with "the", one use with "within a Planck length"
  3. http://ned.ipac.caltech.edu/level5/Glossary/Essay_plancklt.html -- all (2) uses include "the"
  4. http://www4.hcmut.edu.vn/~huynhqlinh/olympicvl/tailieu/physlink_askexpert/ae644.cfm.htm -- all (4) uses include "the"
  5. http://www.nature.com/news/single-photon-could-detect-quantum-scale-black-holes-1.11871 -- 1 use of "the", 2 uses of "a", 1 use of "one", and 1 use of "This".

As such, I've reverted the removals of "the". I'm glad to reconsider if further evidence is provided. 63.251.123.2 (talk) 20:53, 31 October 2013 (UTC)

I've already discussed with you on Talk:scientific consensus that "the" is a definite article in English. What you've showed here are examples, but I can't see what argument they serve as evidence. --14.198.220.253 (talk) 15:33, 5 November 2013 (UTC)
They show usage in reliable sources, which is what we should be following. I did a quick check at google books and the unit is used with the definite article. Garamond Lethet
c
16:40, 5 November 2013 (UTC)
Reliable sources of what? Explain yourself. --14.198.220.253 (talk) 16:18, 8 November 2013 (UTC)
Also, a simple Google search on "Planck length" excluding "the Planck length" returns about 45,800 results. I think it is appropriate to cleanup excessive use of "the" according to WP:CLARITY and readability. To justify the need on definite article, you should show us reliable sources on how there is/are other "Planck length"s which causes possible confusion (or multiple interpretation..) among physicists. --14.198.220.253 (talk) 07:27, 9 November 2013 (UTC)
Every hear of Bronx? Even though disambiguation isn't an issue, we still call it The Bronx. We follow common usage here, and based on Google "the planck length" is overwhelmingly more common. Garamond Lethet
c
07:40, 9 November 2013 (UTC)
Your issue had been discussed many times, see WP:DEFINITE. If you are right, then maybe we should also change the title from Planck length to The Planck length. Moreover, you have misunderstood the edit that it doesn't abolish "the" but only the excessive use of it, it is reasonable to use "the Planck length" for the first time to indicate its unfamiliarity. --14.198.220.253 (talk) 08:57, 9 November 2013 (UTC)

Can you point me to a textbook or well-known paper that follows the style you prefer? Garamond Lethet
c
22:24, 9 November 2013 (UTC)

Which style you don't prefer? To revert the edit you abolish the use of "Planck length", I really would like to hear why. --14.198.220.253 (talk) 18:15, 14 November 2013 (UTC)
Sure. "The" is used consistently in reliable sources. I've looked at the results from google books, I've looked at the results from google scholar, and most sources use "the planck length". I'm going to assume that you have a particular reliable source in mind that doesn't follow this convention. What is that source, and why do you think we should give it precedence? Garamond Lethet
c
20:27, 14 November 2013 (UTC)
Are you playing dumb or you insist that the 4,6000 results above (as you've quoted and seen) do not exist? --14.198.220.253 (talk) 21:06, 14 November 2013 (UTC)
Of course they exist. I've read several of them. You haven't. That gives me a bit of an advantage here.
When used in a table, as a header, or as a parenthetical expression, the article is usually eliminated. So your hits are returning a lot of pages like this one, where the phrase is not used in a sentence, this one where it used as a song title, and this one, which tells you how many miles are in the planck length. If you're not a scientist, I can understand why you might think google hit counts would give you some indication of how scientists use the term. That's an understandable mistake, but it's still a mistake. To make a convincing argument, you're going to need to cite material actually written by scientists. That will be a Google Scholar and, to a lesser extent, Google Books. After looking at a couple dozen heavily-cited papers from the 1980s through 2012, what I'm seeing is, most of the time, physicists write "the planck length" unless it occurs in a title, header, or parenthetical expression. Alternatively, you can ask a physicist, which I can do tonight over dinner. I'll let you know what she says. Garamond Lethet
c
22:00, 14 November 2013 (UTC)
Here's the the (paraphrased) response I received: When say something is   meters long, we are using the meter as the unit of measurement. Likewise, when we say something is   Planck lengths, we need to specify "length" (as there are several different units with Planck's name), and in doing so we are using the Planck length. Does that help? Garamond Lethet
c
00:43, 15 November 2013 (UTC)
Nice, I love to see some actual argument instead of RS of nothing, so we can discuss. Frankly, you can see that Google Scholar's result is 3,410 over 11,900.
But that's not important, because they may subject to the cases you've pointed out. The physicist you've asked is completely right and explained everything completely clear and full well, thank you for that.
However, now we need to go back to the actual edit, which I suspect that we overlooked, since I can't see the relation between the edit and all of the discussion so far. If you happen to read 63.251's complaints a lot, you may overlook it, but it is ok, this mistake is understandable.
Here you can see that none of the case is relevant to discussion. That is, for instance, I do not remove the "the" she mentioned
Planck length is the length scale at...
As you can see, all of the "the" which is removed is on the beginning of name, see WP:THE. That is,
(The) Planck length is the length scale at...
And that one is kept as it should,
There is currently no proven physical significance of the Planck length
so the edit has already differentiated where to specify "length" and what to do with it. (That's what I meant by "I didn't abolish "the"" before, I can't explain myself clearly enough without her effort.) We both stayed correct and the edit is legitimate, unnecessary reverts have caused us lots of trouble. --14.198.220.253 (talk) 23:21, 19 November 2013 (UTC)

Note above, "physicists write "the planck length" unless it occurs in a title, header, or parenthetical expression". The places you removed it from are none of these. And Garamond Lethe's source did not dispute this (as I understand the response) (Garamond, please clarify if needed). Again (see below), WP:THE does not apply -- we are not talking about article titles. Also, while I sympathize with your frustration, please avoid personalizing the discussion, as you did with your various comments about my reverts. 63.251.123.2 (talk) 23:37, 19 November 2013 (UTC)

I'm sorry, perhaps I was being emotional. I should have understood that unnecessary reverts actually wasted everyone time, not just my personal time. So, I corrected the line to "unnecessary reverts have caused us lots of trouble" instead of indicating whose fault, meaning the discussion doesn't worth the time and we better be thoughtful on reverts next time, I hope that should fix it or tell me if you want to remove it.
Back on content,
physicists write "the planck length" unless it occurs in a title, header, or parenthetical expression
I think there is no RS to support this claim, and it has to be false. Counterexamples are plenty and notable, as you can follow the link above. The first few one is obvious, say this one from "Annals of Physics, 1985", "Physical significance of Planck length", "The significance of Planck length in a quantum gravity", "It is shown that Planck length is"..etc.
It is not incorrect that one uses "the Planck length" all the time, but that would be excessively long and noisy, it is trivial to dig up more example outside Planck length that follow similar vein too. I would love to know why you want to keep that. --14.198.220.253 (talk) 00:37, 20 November 2013 (UTC)
Looking at your first link, most of the examples on that page do use "the", just not directly before "Planck length": "the eleven-dimensional Planck length", "exceedthe Planck length"[sic], "the 5-dimensional Planck length". The only examples that lack "the" are three papers by T Padmanabhan (who appears to have an idiosyncratic preference in this area, considering the other sources) and one example of "Planck's length" (which wouldn't have "the" in any case). Your 2nd link is to one of Padmanabhan's 3 papers. 63.251.123.2 (talk) 01:28, 20 November 2013 (UTC)
Continuing to the next page, I see further instances of "the eleven-dimensional Planck length", and "Planck's length", and instances of "the fundamental Planck length", "the 27 dimensional Planck length" and a parenthetical, "(∼ Planck length?)". There are two instance that seems to support your view, the papers by K Nozari, and G Modanese, and one instance I agree with: "measuring time in Planck length units". I don't think any of the disputed uses of "the" are of the form "Planck length Xs", but if so, I apologize, and I'm happy for those ones to have "the" removed. Overall, those two pages rather strongly argue against your claim that omitting "the" is better for clarity or succinctness. 63.251.123.2 (talk) 01:28, 20 November 2013 (UTC)
Both are obviously correct, but the claim that "the Planck length is required" is a strong claim and it is incorrect. This is what you've stated until recently.
A few things should be put into consideration on Wikipedia, when you search papers from Google scholars, the authors already expected you to know what Planck length is, most papers focus on application (or derivation) of Planck length and take "Planck length" as a subject, which is highly likely specific, thus "the Planck length".
Here, we focus on definition and description. As you can see from the article, we often take Planck length as an object, "Planck length is.." and this is called a generic noun.
Imo, generic noun is the most fluent and precise candidate because we are describing its generic means. On the other hand, both generic and specific noun doesn't serve much difference as an object, they both refer to "Planck length".
The reason I point you to WP:THE is that, it serves as consensus that we've decided that "the" is not part of its name (this is what Garamond challenged before), hence the discussion can move on to grammatical preference(WP:MoS) and readability, it would be specific noun vs generic noun.
Btw, I just pick up a link "Physics and Reality" by Albert Einstein on Planck constant, there is a line "Planck's constant h relates the frequency H,/h to the energy values H,.", it is a generic noun. --14.198.220.253 (talk) 05:19, 20 November 2013 (UTC)
First of all, thank you for expanding on your rationale. I appreciate it. I don't think the term "generic noun" is usual in English (at least, I was not able to find much in the way of definitions or descriptions of that term). You did prompt me to see what Wikipedia had to say about English articles, and I found this: Zero article in English. Does that match your explanation? 63.251.123.2 (talk) 18:40, 20 November 2013 (UTC)
Yes, and Wikipedia has not done anything about it yet. Generic noun is *everywhere* in English. "Apple is red.", "Sky is blue."...etc. instead of "The apple is red.", they differ slightly in semantics, "the apple" means a specific apple is red. Well, you also overlooked my quote from Albert Einstein. Do you still think that such grammar is idiosyncratic? --14.198.220.253 (talk) 07:01, 21 November 2013 (UTC)
"Apple is red" and "Sky is blue" are non-standard English, according to my ears. I would write them as: "Apples are red", which falls under "generic plural noun" from Zero article in English, and "The sky is blue", since "sky" can be neither a mass nor a plural noun (at least, not with the usual meaning paired with "is blue"). The quote from Einstein uses the noun phrase: "Planck's constant", not "Planck length" -- that has no bearing on the question of when "Planck length" should take an article. 63.251.123.2 (talk) 17:41, 21 November 2013 (UTC)
Are you looking for lecture or are you sure that you aren't wikihounding me? How can generic noun be non-standard? The overly zero-marking style of language is non-standard, for example, the lack of tenses, but not all zero-(something) you see on that article is non-standard.
"The sky is blue"
Sure, you can use that and never find an inadequacy, because there is only one sky above us, so "the sky" is expressive enough to express what we mean, but it can be exploited in sci-fi.
Apple is different, there are many apples. So,
How about "The apple is red." vs "An apple is red." vs "Apple is red.", the difference is immediate obvious, "The apple is red." specifies a definite apple. "An apple is red" specifies an indefinite but still single apple. "Apple is red." does not specify, both identity and quantity, it is a generic concept/type/set/class, are these countable? I think not.
For example, "I like apple." is exactly what we mean. "Do you like an apple?" "Do you like the apple?" "Do you like apples?" are all too specific. --14.198.220.253 (talk) 15:47, 22 November 2013 (UTC)
I'm sorry, but "I like apple" is still non-standard English. "Apple" is not a mass noun. Neither is "length". That's the problem. I and Garamond have repeatedly pointed this out to you, with many many examples -- including explaining why the examples you have provided are not actually on point. If you don't believe me, I encourage you to request the attention of other editors, and see what they say. 63.251.123.2 (talk) 17:56, 22 November 2013 (UTC)
That's again some big claim. Is abstract noun non-standard? You can't interpret "apple" as an abstract entity(concept)? Your ignorance/absence of abstract noun is non-standard. It also shows that you have not enough understanding to judge which is standard and which is not.
That's what happens to Planck length.
I and Garamond have repeatedly pointed this out to you
Interesting, your argument is vastly different in terms of content and quality. I actually agreed to all of Garamond's point.
including explaining why the examples you have provided are not actually on point
As I responded earlier, none of Garamond's argument addressed the edit (Planck length as an object(grammar)). You deliberately overlooked the examples I've given by claiming that "T. Padmanabhan is idiosyncrasy" "Your grammatical preference is idiosyncrasy." "This is non-standard". --14.198.220.253 (talk) 20:27, 22 November 2013 (UTC)

Er, WP:DEFINITE refers to article titles, not the use of "the" in article text, at least, as I read it. If I misunderstood, please point me to the particular text on that page that supports your claim. Regarding the Google results, I think User:Garamond Lethe did a very good job of laying that issue to rest. 14.198.220.253, you seem to have a number of idiosyncratic grammar preferences -- while you are certainly welcome to them, working on improving the wording of articles might not be the best thing for you to focus on. 63.251.123.2 (talk) 23:17, 11 November 2013 (UTC)

Is the use of "the" missing? Maybe you can read up WP:THE too as referred by WP:DEFINITE.
You also claim that "the" must precede "Planck length", you showed the use of "the Planck length", and you call it "evidence". I have shown you the use of "Planck length" and have yet to see how is it invalid. --14.198.220.253 (talk) 18:15, 14 November 2013 (UTC)
14.198.220.253, you seem to have a number of idiosyncratic grammar preferences -- while you are certainly welcome to them, working on improving the wording of articles might not be the best thing for you to focus on.
Is it even a valid argument? You seem to have a number of idiosyncratic irrelevant concerns -- while you are certainly welcome to them, you can talk to me on my talk page, working on improving the wording of articles might not be the place for you to focus on. --14.198.220.253 (talk) 18:15, 14 November 2013 (UTC)
I'm sorry, but I can't even follow what you are trying to say here. Garamond Lethe has explained quite clearly why you are wrong about "the", and my suggestion to you wasn't an argument, merely a recommendation about how you might chose to spend your time. 63.251.123.2 (talk) 00:27, 15 November 2013 (UTC)
Garamond Lethe has explained quite clearly why you are wrong about "the"
Good point and that's what you didn't do so far.
merely a recommendation about how you might chose to spend your time.
Thank you, it is very constructive. --14.198.220.253 (talk) 23:21, 19 November 2013 (UTC)
And WP:THE redirects to Wikipedia:Naming conventions (definite or indefinite article at beginning of name) which, as it sounds like, concerns article titles, not wording within articles. This was already pointed out to you. 63.251.123.2 (talk) 00:29, 15 November 2013 (UTC)

Bringing this to a close

There are two proposed edits that are amenable to more specific google searches: "square of [the] Planck length" and "Since [the] Planck length".

Google Google Scholar Google Books
square of Planck length 5390 22 1
square of the Planck length 455000 172 565
since Planck length 28400 6 1
since the Planck length 16800 82 75

It's curious that the vanilla ghits are 2:1 in the second case, but as the searches of more reliable material show a preference for "the" I'm comfortable keeping the argument as it is. I sympathize with arguments from grammatical correctness, but that's an argument to be made to journal editors, not here. Garamond Lethet
c
04:26, 25 November 2013 (UTC)

Addition

I added information about the collapse of the photon and the Heisenberg uncertainty principle at the Planck scale (in the proofs). The proofs is here. Alexander Klimets (talk) 16:50, 25 March 2014 (UTC)

Order unity?

I'm not a mathematician, and am confused by this part of the article:

"the Planck length is, in principle, within a factor of order unity, the shortest measurable length"

Is it saying that "order unity" means "the shortest measurable length"? If so, should "order unity" have its own page and should it be italicized or something?50.49.134.141 (talk) 08:04, 21 November 2014 (UTC)

I've linked it as "order unity". It means it's within a factor of 10 of the shortest measurable length. Oreo Priest talk 15:05, 22 November 2014 (UTC)

Length/volume confusion

The sentence at the end of the value section:

"At this scale, more Planck lengths would fit inside a grain of sand volumetrically than grains of sand would fit inside the observable Universe."

makes no sense whatsoever. Length is a single dimension and has zero volume. An infinite number of lengths can fit inside anything. There is no citation on the statement either. I am removing it.Linktex (talk) 16:07, 28 January 2015 (UTC)

Reference 3 does not exist

A lot of the more mathematical claims in this page are supported supposedly by reference 3, but searching for it on google just brings us back to this page. Technically, they make some claims that counter modern physics, include Lorentz invariance, but more importantly, the reference does not exist. The person making these edits is Alexander Klimets, and the reference is to Klimets A, so I think this is also original research. 69.196.172.226 (talk) 13:18, 23 August 2014 (UTC)

Reference 3 exist. See https://www.lap-publishing.com/catalog/details//store/gb/book/978-3-659-16345-6/%D0%9F%D0%BE%D1%81%D1%82%D0%B8%D0%B3%D0%B0%D1%8F-%D0%BC%D0%B8%D1%80%D0%BE%D0%B7%D0%B4%D0%B0%D0%BD%D0%B8%D0%B5 [unsigned, posted by Alexander Klimets]
Reference 3 exists, but has two substantial problems.
1: It was published by Lambert Academic Publishing, which is basically a vanity press. It cannot therefore be considered a WP:reliable source.
2: References to the author's own work added to Wikipedia by the author are a clear WP:CONFLICT OF INTEREST. Klimets is trying to promote his work by adding it here. Combined with point 1, it is also effectively WP:ORIGINAL RESEARCH.
For these reasons, it is important that Alexander Klimets stop editing this article, or at the very least stop adding reference to his own work. Also, any material supported by reference 3 can be considered unsourced, challenged and removed. Oreo Priest talk 20:16, 23 August 2014 (UTC)
I agree to delete all and return to the original view. Alexander Klimets (talk) 21:49, 23 August 2014 (UTC)
I do not agree with the complete removal of the text. There is my article about the collapse of the photon at the Planck scale and three-dimensional space in the journal "FIZIKA B" (Zagreb, 2000) at http://fizika.hfd.hr/fizika_b/bv00/b9p023.htm (reference 4). It is a reliable source. Alexander Klimets (talk) 03:51, 27 August 2014 (UTC)
Sorry Alexander, but your view of the photon's collapse into a black hole is unfortunately not accurate because it requires a special reference frame. We know that one does not exist since the concept of an absolute space does not exist. You can always boost to a reference frame where the photon has an arbitrary amount of energy. Remove the proof as it is inaccurate and betrays a serious lack of understanding of the mechanisms at work here. See here for more relevant discussion: http://www.reddit.com/r/Physics/comments/2edftq/wikipedia_article_on_planck_length_states_that_a/ Michael Waddell (talk) 07:53, 27 August 2014 (UTC)
Hamilton-Jacobi equation is generally covariant (physical content of equations does not depend on the choice of coordinate system). Alexander Klimets (talk) 07:52, 1 November 2014 (UTC)
It is known that the spin of the photon - its internal quantum characteristics, unexplained in the framework of relativistic mechanics. Gravitational collapse of a photon is also a quantum phenomenon, and is outside the scope of relativistic mechanics.Alexander Klimets (talk) 08:49, 6 February 2015 (UTC)
It is not appropriate to promote your own research on Wikipedia.132.206.186.174 (talk) 15:25, 27 August 2014 (UTC)
The system of two photons is considered in reference 4 (above). Alexander Klimets (talk) 01:55, 30 August 2014 (UTC)
It is still probably not appropriate as it's not a secondary source. Please see WP:SCHOLARSHIP for details. Oreo Priest talk 10:26, 1 September 2014 (UTC)
On this subject there is my report on the 5th International Conference on Gravitation and Astrophysics of Asian-Pacific Countries. Moscow, October, 2001,(ICGA-2001). See: http://rgs.vniims.ru/conf6.htm . My report is in the Programme of Scientific Session, October 2, Tuesday, Sections "Relativistic Astrophysics and Black Holes", item 6, title "Geons Are Real Candidates for the Role of Primary Miniholes and Their Implication for Planckian Physics", (A.P.Klimets). See: http://rgs.vniims.ru/program.htm . Alexander Klimets (talk) 06:29, 6 February 2015 (UTC)
The fact that you also presented your work at a conference doesn't change any of the above points, sorry. Oreo Priest talk 20:29, 9 February 2015 (UTC)

The Planck quantum

The Planck quantum doesn't exist in nature and simply is a product of relativistic comparison among various quantum systems. No single exact (mono-)Planck quantum has been ever observed, not because of our failure but because it's relativistic (among systems) and not fundamental (it isn't thoroughly causal because quantum field theory requires some uncertainty of the inputs (from other fields) of the lowest energetically quantum state, thus our result is always relativistic (in relation to the specific experiment and not global). But statistically we can measure the lowest possible quanta and have an approximate opinion about that. — Preceding unsigned comment added by 2A02:587:4113:C400:8D92:8418:8856:6CF1 (talk) 18:56, 3 December 2016 (UTC)

I don't see any "planck quantum" in the article. --mfb (talk) 21:54, 4 December 2016 (UTC)
I think he's talking about Planck units. Sounds good. I move to delete all articles talking about Max Planck. /sarcasm Leostaley (talk) 19:06, 5 December 2016 (UTC)

On the Planck length's significance

A few months ago, this:

There is currently no proven physical significance of the Planck length; it is, however, a topic of theoretical research. Since the Planck length is so many orders of magnitude smaller than any current instrument could possibly measure, there is no way of examining it directly. According to the generalized uncertainty principle (a concept from speculative models of quantum gravity), the Planck length is, in principle, within a factor of 10, the shortest measurable length – and no theoretically known improvement in measurement instruments could change that.[citation needed]

was changed to this:

There is currently no proven physical significance of the Planck length, however, it is theoretically considered to be the quantization of space which makes up the fabric of the universe, also referred to as quantum foam.

Is the latter putting too much certainty on the actual Planck length, as opposed to the theories mentioned elsewhere where the Planck length is believed to be approximately the scale of quantisation (if space is even quantized?)

As written, it implies that space is known to be quantized, which is not the case as I understand it. David (talk) 17:33, 17 May 2017 (UTC)

Removing citation of paper

I attempted to remove the following passage but it was restored by the originator:

It has recently been suggested that the Planck length can be measured independent of any knowledge of Newton's gravitational constant with for example the use of a Cavendish apparatus E. Haug, (2017). Applied Physics Research, Vol. 10, No. 1.. Further it seems like the error in the Planck length measures must be exactly half of that in the measurement errors of the Newton's gravitational constant. That is the error as measured in percentage term, also known as the relative standard uncertainty. This is in line with the reported relative standard uncertainty reported by NIST, that for the gravitational constant is   and for the Planck length is  .

This is silly to report as some kind of recent science breakthrough since given   and  , knowing Planck length is by definition equivalent to knowing the gravitational constant and vice versa. _Obviously_ an experiment that measures one is also an experiment that measures the other. The sensitivity analysis follows from basic mathematics as well. None of this needs to be said.

Also, note Wikipedia should not be used for self-promotion WP:CONFLICT OF INTEREST nor to promote ones own research WP:ORIGINAL RESEARCH. — Preceding unsigned comment added by 24.238.45.249 (talk) 23:05, 6 January 2018 (UTC)

Comment: "Knowing Planck length is by definition equivalent to knowing the gravitational constant and vice versa.", no one has pointed out this before that one can measure the Planck length without knowing the gravitational constant. The whole point is we do not at all need the gravitational constant. — Preceding unsigned comment added by 47.19.222.138 (talk) 01:59, 7 January 2018 (UTC)

How one not should edit?

"24.238.45.249" first just deletes texts and references with the claim "Removed reference to crank paper"

24.238.45.249 should point out explicitly why he/she think the paper is a Crank paper. He/she should point out exactly what he/she think is wrong with the paper. What are the errors? Or is the statement just based on it not is published in a top journal, but a lower ranked journal? Should scientific work not be judged on the work itself? This on a page where there even are references to work just put out on the web without any quality check whatsoever.

Next 24.238.45.249 claims "This is silly to report as some kind of recent science breakthrough " who has said it is a break through what I referred to? wikipedia is a quite basic information provider. What you claims is obvious (after someone already pointed it out to you, on something you first claim is a Crank argument?) is possibly not so obvious at least not for everyone else. For people knowing everything about the Planck length already wikipedia is not very useful.

Next 24.238.45.249 claims: "The sensitivity analysis follows from basic mathematics as well. None of this needs to be said." First 24.238.45.249 cause my reference to be Crank, then some type of too fresh break through work, then so trivial it not need to be referred to or described.

Who is wikipedia for, if it is not to summarize simple facts and information. As the current page stand it do not give proper references to when the Planck length first was described, neither do it explain such very trivial (according to 24.238.45.249) but very important aspects as that the relative standard error is half in the Planck length compared to the gravitational constant.

I tried to improve the page by actually linking to published academic papers supporting what 24.238.45.249 first claimed is Crank before 24.238.45.249 claimed it was some attempt to refer to break through then to the obvious. I also added several references to where the Planck length first was described by Max Planck. Wikipedia is lacking in often not referring to who came up with ideas or where it was first published. — Preceding unsigned comment added by QuantitativeGeometry (talkcontribs) 03:48, 7 January 2018 (UTC)

I cannot understand the end of the Visualization section

The last two sentences of the Visualization section (currently the last section of the article) are as follows:

"All said, the attempt to visualize to an arbitrary scale of a 0.005 mm dot is only for a hinge point. With no fixed frame of reference for time or space, where the spatial units shrink toward infinitesimally small spatial sections and time stretches toward infinity, scale breaks down. Inverted, where space is stretched and time is shrunk, the scale adjusts the other way according to the ratio V-squared/C-squared (Lorentz transformation).[clarification needed]"

That "[clarification needed]" is something I just noticed was already written in the article. The first of the two sentences is unclear to me because I don't know what a "hinge point" is. The second sentence is entirely incomprehensible to me. I hope someone knowledgeable in the subject can fix this. — Preceding unsigned comment added by 2600:1700:E1C0:F340:3526:83FE:7731:8FAB (talk) 05:06, 2 February 2018 (UTC)

Yes, that's nonsense. Need to be deleted — Preceding unsigned comment added by 2A00:CA8:A14:6A01:B66D:83FF:FEFB:2A2A (talk) 21:48, 13 March 2018 (UTC)

Saved hider from article.

Examples
Einstein's equation is
 

where   is the Einstein tensor, which combines the Ricci tensor, the scalar curvature and the metric tensor,   is the cosmological constant,   is energy-momentum tensor of matter,   is the number,   is the speed of light,   is Newton's gravitational constant. This equation can be written as

 

where   is the density of the energy-momentum of matter. In the derivation of his equations, Einstein suggested that physical spacetime is Riemannian, ie curved. A small domain of it is approximately flat spacetime.

For any tensor field   value   we may call a tensor density, where   is the determinant of the metric tensor  . The integral   is a tensor if the domain of integration is small. It is not a tensor if the domain of integration is not small, because it then consists of a sum of tensors located at different points and it does not transform in any simple way under a transformation of coordinates. [1]

Here we consider only small domains. This is also true for the integration over the three-dimensional hypersurface  . Thus, Einstein's equations for small spacetime domain can be integrated by the three-dimensional hypersurface  . Have [2] [3]

 

Since integrable spacetime domain is small, we obtain the tensor equation

 

where   is the  -component of the 4-momentum of matter,   is the  -component of the radius of curvature small domain. Since   then

 

where   is the Schwarzschild radius,   is the four-velocity,   is the gravitational mass. This entry reveals the physical meaning of the   values as a component of the gravitational radius  . Here   (compare  ).

There is a similarity between the obtained tensor equation and the expression for the gravitational radius of the body. Indeed, for static spherically symmetric field and static distribution of matter have  . We obtain

 

In a small area of spacetime is almost flat and this equation can be written in the operator form

 

where   is the Dirac constant. Then commutator of operators   and   is

 

From here follow the specified uncertainty relations

 

Substituting the values of   and   and cutting right and left of the same symbols, we obtain the Heisenberg uncertainty principle

 

Since   and  , then   , where   is the wave 4-vector. That is,   (Schwarzschild radius) is quantized, but the quantization step is extremely small.

In the particular case of a static spherically symmetric field and static distribution of matter   and have remained

 

where   is the Schwarzschild radius,   is radial coordinate. Here   and  , since the matter moves with velocity of light in the Planck scale. Last uncertainty relation allows make us some estimates of the equations of general relativity at the Planck scale.

For example, the equation for the invariant interval   in the Schwarzschild solution has the form

 

Substitute according to the uncertainty relations  . We obtain

 

It is seen that at the Planck scale   spacetime metric is bounded below by the Planck length, and on this scale, there are real and virtual black holes.

The spacetime metric   fluctuates and generates a quantum foam [4]. These fluctuations   in the macroworld and in the world of atoms are very small in comparison with   and become noticeable only on the Planck scale. The formula for the fluctuations of the gravitational potential   agrees with the Bohr-Rosenfeld uncertainty relation  .[5] and with the detailed analysis of gravity field measurements by T. Regge.[6]

The second example.The speed of light has the form in a gravitational field:  . Therefore, the fluctuations in the speed of light on the Planck scale are  . Here   is the gravitational potential,   is the wavelength of light. The photon velocity fluctuations are determined by the value of   (but not by  ), so that these fluctuations are immeasurably small and the images of distant stars will be sharp even at metagalactic distances.[7]

An analysis of the Hamilton-Jacobi equation in spaces of various dimensions on the Planck scale showed that the appearance of virtual black holes (quantum foam, the basis of the "tissue" of the Universe) is energetically most profitable in three-dimensional space.[8] This may have predetermined the three-dimensionality of the observed space.

In an attempt to clean up the article, I've removed this section. It's beyond my capabilities to fully understand, but I question its appropriateness for a Wikipedia article. Additionally, it seems to be arguing for a theory of quantum foam, which as far as I know, is not yet an accepted theory of physics. I've saved it here so that someone more well-versed in physics can reincorporate the material appropriately. cnte (talk) 07:38, 23 March 2018 (UTC)

References

  1. ^ "Dirac.pdf". vk.com., p.37
  2. ^ "Klimets_A_P_Postigaya_mirozdanie.pdf". vk.com., p.81
  3. ^ "Quantum gravity.pdf". vk.com., p.25
  4. ^ "Quantum foam". New Scientist. Retrieved 29 June 2008.
  5. ^ Borzeszkowski, Horst-Heino; Treder, H. J. (6 December 2012). The Meaning of Quantum Gravity. Springer Science & Business Media. ISBN 9789400938939.
  6. ^ T. Regge, Nuovo Cim. 7, 215 (1958). Gravitational fields and quantum mechanics
  7. ^ John Whitfield, "Sharp images blur universal picture", Nature, (31 March 2003).
  8. ^ Klimets, Alexander P (2000). "Geons - Candidates for the Role of the Initial Microblack Holes and Their Importance for the Planck Physics". Fizika B. 9: 23, § 4. Bibcode:2000FizB....9...23K.,

Planck length geometry

It seems to me that geometry at the Planck length cannot be Euclidean. Since a fractional value of a Planck length is nonsense, then there would be no way of measuring the hypotenuse of a right triangle with arms 1 Planck length long. How would one measure the circumference of a circle with a radius of 1 Planck length (note the impossibility of a diameter equal to one Planck length--"diameter" implies two radii--each 1/2 Planck-length long)? What kind of geometry WOULD apply at the Planck length level? Is there a point at which geometrical measures in Planck-length units greater than 1 WOULD consistently yield Euclidean values in all cases (i.e., no fractional values smaller than a Planck length)? If the geometry is indeed non-Euclidean, what kind of geometry would make sense at this level? Is it possible that this geometry might suggest physical properties of interest?

Marringtontoo (talk) 06:06, 8 August 2009 (UTC)

From http://www.blazelabs.com/f-u-const.asp :

Arguments showing why h-bar (Dirac's constant ) should NOT be used to derive Planck units Unfortunately, a lot of scientific literature state Planck units expressed in terms of (=h/(2p)) known as Dirac's constant, or the reduced Planck's constant. THIS IS INCORRECT. The 2p factor in fact leads to totally different (and wrong) numeric values for Planck units, than the original values set out by Planck himself. The 2p factor is a gratuitous addition, coming from the failure to address the Hydrogen atom's stable orbits as defined by the orbital path length being an exact multiple of the orbital matter (standing wave) wavelength. The statement that the orbital electron's angular momentum is quantised as in: m.v.R = n.(h/2p) = n. for integer values of n, is just a mis-statement of 2p.R = n.h/(mv) .... which when substituting for h=E/f, v=f.l, and m=E/(f.l)2... we get: 2p.R = n.l ..... which means that the 2p factor has nothing to do with h as such, and that the orbital path is just an integer number of wavelengths as described by Louis De Broglie! (see diagram above). Dirac's was thus defined due to lack of understanding of the wave structure of matter, and its use should be discouraged. Some physicists still prefer to use h-bar, not for any scientific reason, but mostly for the sake of simplicity in their calculations. —Preceding unsigned comment added by 78.108.52.23 (talk) 03:04, 25 October 2009 (UTC) ~~ Magmatrix


If I understand correctly, the classical (non-quantum) way of looking at it is just to say that your measurement uncertainty of any length is always at least the Planck length. So, you'd measure the hypotenuse to be 1.5 Planck lengths long, but plus or minus at least 0.5 Planck lengths. Trying to triangulate more precise positions by making many measurements stops working, due to this uncertainty.
Nobody's quite sure what the quantum gravity picture ends up looking like. The loop quantum gravity people propose that spacetime ends up being a lattice of nodes of roughly Planck length (and Planck time) size, if I understand correctly. Whether the resulting geometry is Euclidean or non-Euclidean depends on how these nodes connect to each other. --Christopher Thomas (talk) 06:19, 8 August 2009 (UTC)
User Marringtontoo says, "note the impossibility of a diameter equal to one Planck length--'diameter' implies two radii--each 1/2 Planck-length long". This seems to be a trick of semantics. Does the idea of "circle" imply "center"? Does it imply "two semicircles"? Perhaps the idea of a diameter only seems to imply the idea of two radii because that's the way you think of it. Unfree (talk) 20:31, 19 October 2009 (UTC)
Space can fail to be Euclidean for various reasons. It might be curved but still support notions of continuous angle and length, as with the hyperbolic geometry of Lobachevsky (et al). Or it might be flat but with only limited notions of angle, length, and area and no notions of right angle, rectangle, square, or circle, as with Euler's affine geometry. Or it might support right angles but not be able to subdivide them, so you could have squares and rectangles but not triangles or circles and rotation would be in discrete multiples of a right angle, basically the geometry of free abelian groups, aka Zn. Lots of possibilities to speculate about down there. Perhaps the wars of the next millennium will be fought over choice of geometries at the Planck length instead of how to pray to whom. --Vaughan Pratt (talk) 05:55, 2 November 2009 (UTC)
I came here wondering something similar to this. Imagine you have two photons, having been emitted from the same point, and traveling along lines that diverge by only one angular degree. Say at Planck time T they are L Planck length units from each other. Then at Planck time T+1 they must be some non-integer Planck length units apart. But no, you're saying they remain (most likely) the same distance apart for a while, but as they travel the probability gradually increases that they are now L+1 Planck length units apart. Is that it?
In other words, it is a little bit like the anti-aliasing that takes place in digital photography, with pixels along a diagonal edge. 129.219.155.89 (talk) 21:31, 28 September 2011 (UTC)
Get a grip man. Just because it can't be measured does not mean it does not exist. 31.185.241.136 (talk) 02:24, 26 March 2014 (UTC)
So you're saying two photons could be a non-integer number of Planck units apart, but we can never hope to measure that? 129.219.155.89 (talk) 18:45, 12 June 2014 (UTC)
Planck length and Euclidean geometry. The gravitational field performs zero-point oscillations, and the geometry associated with it also oscillates. The ratio of the circumference to the radius varies near the Euclidean value . The smaller the scale, the greater the deviations from the Euclidean geometry. Let us estimate the order of the wavelength of zero gravitational oscillations, at which the geometry becomes completely unlike the Euclidean geometry. The degree of deviation   of geometry from Euclidean geometry in the gravitational field is determined by the ratio of the gravitational potential   and the square of the speed of light  :  . When  , the geometry is close to Euclidean geometry (metric coefficient  ); for  , all similarities disappear:  . The energy of the oscillation of scale   is equal to   (where   is the order of the oscillation frequency). The gravitational potential created by the mass  , at this length is  , where   is the constant of universal gravitation. Instead of  , we must substitute a mass, which, according to Einstein's formula, corresponds to the energy   (where  ). We get  . Dividing this expression by  , we obtain the value of the deviation  . Equating  , we find the length at which the Euclidean geometry is completely distorted. It is equal to Planck length  m. Therefore deviations from Euclidean geometry ( ) on the Planck scale are equal to:  . When  , a quantum foam appears - wormholes and virtual black holes. 178.120.0.114 (talk) 08:56, 31 March 2018 (UTC)

Planck Length edit by user:EntropyFormula

This edit is copied from User talk:EntropyFormula:

In your [1] edit on Planck Length you gave as a journal article reference to the text you inserted "E. Haug, Can the Planck Length Be Found Independent of Big G, Applied Physics Research, Vol. 10, No. 1. (2017)". I cannot find this article in the journal you cite. Please can you clarify? Xxanthippe (talk) 00:25, 20 September 2018 (UTC).

It is there, just google "Can the Planck Length Be Found Independent of Big G" and look at one of the links google gives you.— Preceding unsigned comment added by EntropyFormula (talkcontribs) 18:44, 20 September 2018 (UTC)

The correct reference to the paper is Applied Physics Research 9,(6) 2017. Not as in the article. This paper has only 9 citations in Google Scholar, every one of them a self citation. I have removed the section as being of inadequate notability for the article. I note that all of your edits are to topics connected to Espen Gaarder Haug. Do you have any connection with this person that would amount to a WP:COI. If so you should declare it. Xxanthippe (talk) 04:27, 22 September 2018 (UTC).
I have removed the section from the article as it is inadequately sourced. My browser did not allow me to add an edit summary. Xxanthippe (talk) 04:32, 22 September 2018 (UTC).

Is this how Xxanthippe judge recently published science? by how many citations? It can take years before published papers get well cited. Are you not capable of studying the simple math and understand how a Cavendish apparatus works and understand that the Planck length can be measured independent of the Newton's gravitational constant. Yes if this was a very complex proof with new exotic math one could naturally claim one had to have many citations first. But that is not the case, it is based on simple high school math combined with basic physics. Have you ever done experimental research with a Cavendish apparatus, do you understand the simple derivations in the paper (that is shown step by step in the appendix of the paper) ? Exactly what do you claim is wrong with the derivations or the use of Cavendish apparatus?. You can add discussion to the topic, or claim such as hopefully further research will better confirm this, but please stop deleting things simply not in your taste. If you only can judge published work based on where published and the number of citations and edit wikipedia only based on that, then what shall we do? Or will you claim wikipedia only is for old science and old papers where the published science have many citations already? Look around wikipedia and you will see this is not the case. I look forward to your comments Xxanthippe, but please relate them to science, number of citations is not very relevant. EntropyFormula (talk) 07:30, 22 September 2018 (UTC)

Wikipedia judges the notability of a subject by the note taken of it by multiple, independent reliable sources. Wikipedia is not a forum for the publication of original research. In this case nobody has taken any interest in the paper referred to apart from the nine self-citations[2] of its author. I propose the deletion of the section Planck length#Measuring the Planck length on the grounds that it relies on a source of insufficient notability. I note that you have not denied a WP:COI in this matter. Xxanthippe (talk) 00:46, 24 September 2018 (UTC).
Yes, delete it. The author lives in his own world in terms of publications, citing himself over and over again without reception from others. These works including topics like a "maximum velocity formula for matter" or very basic fallacies (essentially claiming "if a higher speed would be physically possible then it must happen frequently in this world").
Anyway: The result in the paper is a trivial exercise in arithmetic. It is just expressing formulas in a different way. Sure, you can express G in terms of the Planck length and other constants and plug that into the formula where you would typically calculate G. That is nothing new. --mfb (talk) 07:26, 24 September 2018 (UTC)
I concur with the deletion. XOR'easter (talk) 21:29, 24 September 2018 (UTC)

That something is trivial (when someone has pointed it out for you) dose not mean it not is important. No one has shown how to measure the Planck length before without any reliance on Newtons's gravitational constant. Not one good scientific argument has been given to prove the method wrong, why one has peer review. If one think a published paper is wrong one should write a paper about it and get it published. That is the scientific method, not to try to attack persons, or just come with general statements as trivial or not cited enough. — Preceding unsigned comment added by EntropyFormula (talkcontribs) 09:37, 26 September 2018 (UTC)

As you note, It can take years before published papers get well cited. Most editors are not physicists. It's not our job to evaluate or judge physics research. It is not Wikipedia's job to lead in the forefront of physics research. It is our job to evaluate whether other physicists (and the world) have taken significant note of the result, and afterwards to summarize that information. If and when other physicists consider the work to be significant, then we can reconsider adding it to the article. Alsee (talk) 20:30, 1 October 2018 (UTC)

Potential reference

The Constants of Nature, Barrow, 2002, isbn=0-375-42221-8

Chapter 2 includes some history of the Planck units. Chapter 3 mentions some of the significance of the units. It mentions Planck area and information storage.

The book cites sources.2605:E000:1F01:4AED:83C:2FF4:CA2F:BEA (talk) 18:50, 17 December 2018 (UTC)

The Plank units page cites Barrow and others. Is this page required?159.83.196.1 (talk) 00:15, 20 December 2018 (UTC)

Generally if using secondary sources, like Barrows appears to be, we don't need to cite their original sources. If you want to use that reference as a source (if you have access to it or can provide access to other editors) that'd be great! Otherwise, I'm not quite sure the question you're asking? Captain Eek Edits Ho Cap'n! 00:03, 26 December 2018 (UTC)

Two different values?

Hello, This article gives two different values for ℓP: 1.616255(18)×10^−35 m (via `physconst`) and 1.616229(38)×10^−35 m. The first one has a source but the second one has not. The French article for Planck length had the same problem. Several people updated the second value to be equal to the first one, but every edits were reverted. I don't understand why. Is it necessary to quote the source for the two occurrences of the value? Thank you.--Hypesnave (talk) 08:36, 10 August 2019 (UTC)

The Planck area is the area by which the surface of a spherical black hole increases when the black hole swallows one bit of information

This is wrong, Plank area contains 1/4 nat of information.--Reciprocist (talk) 02:30, 8 December 2018 (UTC)

A reliable source will have to be found for these claims. Xxanthippe (talk) 02:42, 8 December 2018 (UTC).
1/4 "nat"? Did you mean "bit"? Also I agree, you need a reliable source to back up the claim. Since the content is currently sourced and no counter evidence has been provided, I support removing the dubious tag. Captain Eek Edits Ho Cap'n! 04:02, 8 December 2018 (UTC)
In thermodynamics entrypy is measured in nats multiplied by Bolzmann konstant. BH entropy is   This means that in nats it is   that is, 4 plank lengths squared contain 1 nat of information. One plank length squared thus has 1/4 nat. — Preceding unsigned comment added by Reciprocist (talkcontribs) 12:47, 20 December 2018 (UTC)
Reciprocist I stand by what me and Xxanthippe said earlier, per the pillars of Wikipedia, you'll need a reliable source to back up those claims. Currently the in-text source (which seems reliable, although a bit old) says that the Planck area is one bit. If you can find a more modern text that updates us on how much information is in a Planck area, please add it here as a reference! On another note, please remember to sign your talk page edits with 4 tildes "~", that makes it easier for editors to keep track of conversations. And not to be a grammar goblin, but I recommend you proofread your comments before you post -- I do it all the time, it ensures that I don't post any embarrassing typos! Captain Eek Edits Ho Cap'n! 20:55, 20 December 2018 (UTC)
I linked the article on BH entropy which contains the said formula.--Reciprocist (talk) 22:32, 20 December 2018 (UTC)
The BH entropy article doesn't mention the word "nat" or "bit" once. At this point, your claim is original research -- which can't be put onto Wikipedia. Unless you have a reliable source that states "the Planck area contains 1/4 nat of information" we can't include that claim. Captain Eek Edits Ho Cap'n! 23:19, 20 December 2018 (UTC)
This is the original Bekenstein's article which this article currently cites: http://www.cbpf.br/~cirto/MecEstNaoExten_HTML/AULAS/Aula_12/Bekenstein_(Black_Holes_And_Entropy)_%5BPRD_1973%5D.pdf On page 7 it says "in our units one bit is equal to ln 2 of information". This clearly shows that they use nats as units (1 bit = ln 2 nat). Anyway, this article should not be used as a source because it uses outdated expression for black hole entropy (the modern formula was discovered by Hawking the following year, 1974)--Reciprocist (talk) 13:21, 23 December 2018 (UTC)
Hmmm you are right, the article does say that. But from what I see from that source, it does not mention black hole area in relation to Planck area. I am a fan of removing the sentence altogether, considering that this article is about the Planck length not the Planck area. I still encourage you to find a more modern source if possible and re-add information where it is relevant. Captain Eek Edits Ho Cap'n! 22:07, 23 December 2018 (UTC)

Ironically; the sentence CaptainEek would like to excise is the one that talks about the Planck area, which some theoretical physicists think is more fundamental than the Planck length. In some sense; the importance of the Planck length is that it allows us to construct areas and volumes of spacetime, so length is less fundamental than area. This is due to the fact that at the Planck scale, reality becomes 2-d, according to the Holographic principle. Steven Carlip wrote about Spontaneous Dimensional Reduction, stating that almost all quantum gravity theories have this feature at the Planck scale. I think this notion should be highlighted, not excised. Regards, JJD JonathanD (talk) 05:12, 29 October 2019 (UTC)

If you have a good source that can relate the length to the area, that would be worthy for inclusion. I just didn't want it added previously as the source was silent on that point. Captain Eek Edits Ho Cap'n! 05:43, 29 October 2019 (UTC)
Probably the right thing to do initially is to change the wording to express proportionality. There is little controversy with that since most use Hawking's 1/4 proportion, and I can scout that reference. But perhaps a brief tutorial is in order because the Planck length's fundamentality as a space-like extent is not independent of the fact that the simplest possible space container is 2-d (a triangle or circle). This is intimately connected with open questions in the quantum gravity regime, which is a topic I'm especially fond of.
I think Gerard 't Hooft was the first to make explicit the notion that reality becomes 2-d near the Planck scale, and that this relates to its information content, in his famous paper "Dimensional reduction in quantum gravity" that ushered in the holographic paradigm. More recently; Steven Carlip wrote a paper on "Spontaneous Dimensional Reduction" which talked about this being a universal feature of virtually all QG theories. I've had the pleasure to hear their lectures and meet both Gerard and Steven at Physics conferences.
There is a nice article by Bekenstein in Scientific American that sums this up "Information in the Holographic Universe" at https://www.scientificamerican.com/article/information-in-the-holographic-univ/ which might be good to link to. I was looking at Chap 44 in Misner, Thorne, and Wheeler "Gravitation" this morning and it has useful insights but is not the exact reference to use. I will see if I have a more appropriate textbook to reference here.
More later,
JJD JonathanD (talk) 17:59, 29 October 2019 (UTC)
I should add...
This dimensional reduction is seen by almost all theoretical physicists as applying to Black hole event horizons, at least or explicitly for the case of Schwarzschild Black Holes which have no spin or charge, and therefore present a flat surface. It is too easy to be sloppy with a topic like this however, which the author of the sentence was, but there are appropriate references I am sure. And I will scout them out while thinking about a more precise rewording.
Best, JJD JonathanD (talk) 18:12, 29 October 2019 (UTC)

A fundamental issue here

There seems to be a disconnect with this topic...

I am happy to see it is now listed as high importance, but I see some informative and detailed Physics has been edited away. I also see some objections were raised by people who are not well informed on what the current consensus in theoretical Physics happens to be. Instead; we are caught with an insistence on following the rules of evidence, and using only sources with high citations, for a topic where uncertainty is maximal by definition. So if we were being honest; weasel words would be a necessity, in some cases. Unfortunately; the insistence on secondary or tertiary sources insures the information in this article will be 20 years out of date.

I would rather not see this important topic get degraded with a wealth of outdated information. I will attempt to bridge this gap, and revisit the topic from time to time. There is a lot here that needs correction or clarification. But I see that many of the objections raised address issues treated by the theoretical Physics community years ago, and the misunderstanding of some Science writers has exacerbated the problem. Essential references are missing. I think 't Hooft's paper on dimensional reduction in quantum gravity should be referenced, as connecting information theory and gravity. But there was a Scientific American article by Bekenstein worth citing here and other sources that can add understanding.

I have attended lectures by some of the experts in Planck scale dynamics, or spoken with them, and I will attempt to bridge the gap in understanding if I can.

Regards,

Jonathan JonathanD (talk) 05:01, 29 October 2019 (UTC)

@JonathanD: Thanks for agreeing to take a look at this article! Its been on my watchlist a while, but I'll admit I'm no expert in quantum physics. Any effort to not only improve the sourcing, but also the readability to the average person, would be great! A note on sources: current scientific papers published in reliable journals are usable sources here. No need for the sources to be out of date. Captain Eek Edits Ho Cap'n! 05:33, 29 October 2019 (UTC)
Thanks Captain,
I don't want to be a conquering hero or whatever. There is a statement referenced to John Baez (whom I like) about a lack of theories where there is a Planck scale lattice but this is a feature in Hagen Kleinert's 'World Crystal' model and in the work of B.G. Sidharth; he describes an array of Planck scale oscillators, so the statement is not exactly true, even though it mimics what John said. I never met Kleinert, though we did present at the same conference once, but I have had several engaging conversations with Sidharth. So the question arises; is it more important to be precisely accurate, or to hew to more mainstream sources?
The reason why the Planck length is a vital topic in Physics is mainly about Quantum Gravity, and I am fairly familiar with the current mainstream views. I attended most of the QG lectures at GR21 in NYC a few years back, so I have a good broad overview of the leading edge, ..well almost. I've met more than half of the people on Wikipedia's list of QG researchers, at this point. I was supposed to be at GR22, and my work was presented, but I didn't make it because my Dad was in the hospital, so now I'm a few years behind. The fact I'm more of a Science writer than a scientist might make me better equipped than some to offer corrections though, and to find less-technical way to explain some things.
Best, JJD JonathanD (talk) 18:55, 29 October 2019 (UTC)

Added Visualisation

Don’t remove this. It helps people get an idea of the scale.

“ The size of the Planck length can be visualized as follows: if a particle or dot about 0.1mm in size (which is at or near the smallest the unaided human eye can see) were magnified in size to be as large as the observable universe, then inside that universe-sized "dot", the Planck length would be roughly the size of an actual 0.1mm dot. ” 86.93.208.34 (talk) 05:08, 12 May 2020 (UTC)

The lead

@Quondum: As you can see, I have struggled back and forth trying to clean up this article and make it both accurate yet accessible. You seem to have a good grasp on the subject, so perhaps I can pick your brain a bit. One of the most common misconceptions I see about this is that it is the smallest possible length, and thus I have attempted to try to explain the issue in several different ways. As it reads, I don't think the lead is very accessible. While we do need to present an appropriate level of complexity, our readers are not theoretical physicists. So if you have any suggestions on how to accurately, yet accessibly add a layman's description to the lead, that would be helpful :) AdmiralEek (talk) 17:20, 4 May 2021 (UTC)

The only sense in which the Planck length is a minimum that I'm aware of is as an approximate lower limit on the effective size of a physical object in its rest frame: anything must be larger as a classical object, as a black hole's horizon diameter or as the spread of its quantum wavefunction. Of course, there is no exact minimum because the definition of size is fuzzy. Uncertainty in the sense of quantum foam is another poorly understood thing, evidently, but again one needs to be careful of what one means by a "minimum". There are contexts in which smaller lengths make sense theoretically (e.g. the de Broglie wavelength of a heavy object). It is just that this topic seems to attract a lot of unscientific claims of extremality on WP and elsewhere.
IMO, this article should be trimmed dramatically and merged with Planck units. It really only makes sense in that context. Due to strong push-back from various editors at times, both articles have accumulated a lot of dubious material. Effort would be far better spent improving Planck units. I occasionally tinker here to try to strip out a bit a nonsense, notwithstanding that I think it should be merged. Maybe that is because bold moves have lead to wars before. —Quondum 18:40, 4 May 2021 (UTC)
I would support a merge if proposed, I could see Planck Units being taken to GA, but I struggle to see this page ever improving that much. CaptainEek Edits Ho Cap'n! 19:26, 4 May 2021 (UTC)

on behalf of theoretical physics

Foszae (talk) 01:21, 7 May 2021 (UTC) Ugh, excuse for breaking rules and bad wikiquette. But "as a theoretical physicist" i use the phrases planck length and planck moment and the only scientific fact i want to quote in discussion is "go look up how decimal places small it is." Wave hands in air, say String vibrates. I will likely never need better science as per the Planck units article in practically any discussion i'll lead. Leaving a messy controversial entrance into theoretical physics positively DELIGHTS me that it can be so accessible yet strange. I'm a theoretician therefore "bad scientist" in not having reproducible nor needing exacting magnitudes of measurement. I need to draw on the black board this: 1 whatever dot 000 000 000 000 000 000 000 000 000 000 000 000. Thank you

Theoretical significance

Second paragraph here is backed by two references. One established reference, but where I cannot find backing for what is stated here, and an unpublished reference. I would recommend this paragraph therefore to be removed, or one need to come with published references. Is this paragraph simply not promoting a unpublished paper on a non peer reviewed idea? Cosmology2 (talk) 21:50, 6 July 2021 (UTC)

So much of the second paragraph under section "Theoretical significance" seems to be based on a single non-published paper posted on vixra and the open archive philpapers. I do not think a wikipedia page paragraph/section should be simply based on a single unpublished paper. More reliable sources should be used, the page need revision, there are also several fact errors on the page actually.Cosmology2 (talk) 07:21, 7 July 2021 (UTC)

Cosmology2, what's the problem? Delete this paragraph.

    • please give us links that we can look at (the links above seems to need some subscription or so), if arXive has plagiarized articles they should delete them, and yes in general I think wikipedia paragraphs for science related pages should be backed by published research, and not by something just posted on arXive or other similar platforms. But, naturally if published research do not refer to someone that put out idea on pre-print archive before them then one should link also to that. Cosmology2 (talk) 08:46, 19 July 2021 (UTC)
      • Here is a link to three Arab authors in arXiv.org: https://arxiv.org/abs/1703.10038 (2017). Unfortunately, links to viXra are rejected by Wikipedia. But it can be found under the title of the article "To the quantum theory of gravity.Klimets A.P. (2015) "at: vixra.org/abs/1507.0149 . There are links to arXiv everywhere in Wikipedia, this is considered a publication. 178.120.70.133 (talk) 03:38, 20 July 2021 (UTC)

"Unfortunately, links to viXra are rejected by Wikipedia" by whom? If an idea comes from viXra or any other preprint platform first, then it should be linked to even if it was the same idea later in Nature or Science. My main point is I cannot find any information about what is claimed in that paragraph on the pages of the well known Charles W. Misner, Kip S. Thorne, John Archibald Wheeler "Gravitation", Publisher W. H. Freeman, Princeton University Press, (pp. 1190–1194,1198–1201). Cosmology2 (talk) 21:55, 20 July 2021 (UTC)

  • Links to viXra are automatically rejected. Try it. The authors you mentioned have correct statements about virtual black holes and wormholes (quantum foam) on the Planck scale. But they mistakenly made an analogy with electrodynamics. Therefore, they got  , but not  . Otherwise, everything is correct. 178.120.10.125 (talk) 05:06, 21 July 2021 (UTC)
    • "Links to viXra are automatically rejected. Try it." That is ridiculous, I mean that they automatically reject any pre-print archives, the papers first mention an idea should naturally be mentioned, any thing else is highly scientifically unethical. Someone in the wikipedia admin should look into this. Cosmology2 (talk) 21:17, 27 July 2021 (UTC)
      • "There are links to arXiv everywhere in Wikipedia, this is considered a publication." arXive has many unpublished papers, this has not been peer reviewed in any form. arXive also have many quality published papers. A paper put on arXive that not is published should therefore be treated like any other non published papers, that is the papers should be considered on its own. arxiv is in no way a quality stamp on a paper, they have many quality papers, and also a series of junk papers.Cosmology2 (talk) 21:36, 27 July 2021 (UTC)
      • I agree with you. Some friend deleted the content. Very sorry.178.120.49.111 (talk) 02:55, 28 July 2021 (UTC)