Talk:Planck units

User:Tercer deleted section "Relationship the Planck length to mass m_A = αm_P" under the guise (remove obscure fringy source). What is unclear about this source?
Abdukadyrov, А. (2020), "Fundamental Values of Length, Time, and Speed", Reports in Advances of Physical Sciences, 4 (4): 2050008 ^[5]. -- Aab64 (talk) 06:02, 11 May 2025 (UTC)

Sorry, I don't think this content has sufficient encyclopedic value to be retained. According to Crossref, it has been cited once, and even that is a self-cite. Jähmefyysikko (talk) 07:03, 11 May 2025 (UTC)

If the article is unknown, it does not mean that it cannot be cited. Its importance is that it shows: the Planck length is associated with two completely different masses at once, ${\displaystyle m_{\text{P}}}$ and ${\displaystyle m_{\text{A}}}$. -- Aab64 (talk) 05:16, 15 May 2025 (UTC)

By the way, if according to Crossref this was only cited once, then it turns out that this conclusion has not been refuted by anyone and it is correct! Am I right or not? -

Aab64, the issue is not whether it has been refuted. We don't add every paper written about a topic to that topic. Only the ones that have become significant as shown by people independent of the original author finding them significant enough to include in their work. StarryGrandma (talk) 21:01, 15 May 2025 (UTC)

In the section "Analysis of the units" (Planck length) it is written: "... reduced Compton wavelength is comparable to its Schwarzschild radius".
This is not true, e.g., for the Planck mass ${\displaystyle {\frac {\hbar }{m_{\text{P}}c}}={\frac {Gm_{\text{P}}}{c^{2}}}}$,
i.e. the Compton wavelength and half of the Schwarzschild radius are the same. The inaccuracy needs to be corrected.
212.241.20.141 (talk) 09:19, 5 June 2025 (UTC)

This article contains the following sentence:

Compared to Stoney units, Planck base units are all larger by a factor ${\textstyle {\sqrt {{1}/{\alpha }}}\approx 11.7}$, where ${\displaystyle \alpha }$ is the fine-structure constant.

I added a Why? template, and it was reverted with the following comment:

it's not clear what this template is asking for; the statement being tagged is just a mathematical fact

I strongly suspect the reverter knows much more about this subject than I do, perhaps so much so that they are unaware of how people with lesser experience might read this article. I taught science in a museum setting for 15 years, and if a smart kid came up to me and asked "Why is this sentence true?" I frankly could not answer it. In researching this I see that the fine-structure constant has a direct relationship with the reduced Planck constant, and which I assume is the source of the difference, but an explanation in English would help the uninitiated. I ask that consideration be given for a better explanation of why this "fact" is true.

Thanks. Tfdavisatsnetnet (talk) 00:50, 15 August 2025 (UTC)

@Tfdavisatsnetnet: Re “Why is this sentence true?”: Simply put, because they are mathematically defined as such. In particular:

• The Stoney length is defined as ${\displaystyle l_{\text{S}}={\sqrt {\frac {\alpha \hbar G}{c^{3}}}}}$, whereas the Planck length is defined as ${\displaystyle l_{\text{P}}={\sqrt {\frac {\hbar G}{c^{3}}}}}$
• The Stoney mass is defined as ${\displaystyle m_{\text{S}}={\sqrt {\frac {\alpha \hbar c}{G}}}}$, whereas the Planck mass is defined as ${\displaystyle m_{\text{P}}={\sqrt {\frac {\hbar c}{G}}}}$
• The Stoney time is defined as ${\displaystyle t_{\text{S}}={\sqrt {\frac {\alpha \hbar G}{c^{5}}}}}$, whereas the Planck time is defined as ${\displaystyle t_{\text{P}}={\sqrt {\frac {\hbar G}{c^{5}}}}}$
• The Stoney charge is defined as ${\displaystyle q_{\text{S}}={\sqrt {4\pi \epsilon _{0}\alpha \hbar c}}=e}$, whereas the Planck charge is defined as ${\displaystyle q_{\text{P}}={\sqrt {4\pi \epsilon _{0}\hbar c}}}$

It's like if I define two variables, a = 2 and b = 4, and then you ask me why b is twice as big as a. The answer is: because I defined the two variables as such. To be even more precise,

• you get the Planck units if you define c = 1, G = 1, ħ = 1, k_B = 1, and k_e = 1
• you get the Stoney units if you define c = 1, G = 1, αħ = 1, k_B = 1, and k_e = 1

Why does one system define ħ = 1 whereas the other defines αħ = 1? No reason in particular. --Grufo (talk) 18:30, 6 September 2025 (UTC)

I suspected something like this would be the answer. Can the text be improved to make it obvious? Perhaps without all this detail? Thanks for your effort here! Tfdavisatsnetnet (talk) 23:37, 23 September 2025 (UTC)