Albert Einstein’s sentiment is particularly appropriate in this context:

“As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.”

In my article “Beyond Time: A Non‐Temporal Model Predicting the Composition and Scale of the Universe: A Stereographic and Absorptive Framework Independent of Time‐Based Dynamics”—published in my book Standard and Alternative Cosmology (https://shop.bookmundo.com/en-GB/search?query=Mullat)—I have calibrated the gravitational potential energy function, traditionally given by -G \cdot m / r, to the modified form -G \cdot m / r^\lambda, where \lambda = 0.83751, rather than the classical value of 1, as prescribed by the inverse-square law.

Is the inverse square law not equivalent to gravity being a long range interaction?

The thread question

“Has the inverse square law ever been doubted? …..In particular, with respect to the estimation of type 1A supernova distance based on luminosity?”

- is answered in the mainstream cosmology, as that the inverse square law is undoubtedly true, but really that is true only on rather small cosmological distances ~ a few hundred millions of light years.

On larger distances application of the law well possibly results in some mistakes, because of the cosmological observations are made principally in the 3DXYZ space, where photons/light propagate; and the data are analyzed in the postulated in mainstream physics Matter’s 4D pseudo-Riemannian spacetime with 4D metrics ( ict,X,Y,Z), where “i” is imaginary unit.

Really, as that rigorously scientifically shown in the Shevchenko-Tokarevsky’s Planck scale informational physical model, two main papers are https://www.researchgate.net/publication/391209088_The_Informational_Conception_and_Basic_Physics, and

https://www.researchgate.net/publication/367397025_The_Informational_Physical_Model_and_Fundamental_Problems_in_Physics

- Matter’s utmost universal “kinematical” spacetime has [5]4D metrics (cτ,X,Y,Z,ct), , where ct is real time dimension; while the really the space cτ-dimension in mainstream physics is postulated as is the time dimension.

At that everything in Matter constantly , always, and from Matter’s creation ct-time moment, moved/moves in the 4Dct,X,Y,Z space, and in parallel in ct-dimension, with the speed of light; correspondingly what is observed in cosmology is some strange image of what is/happens really,

- and this is postulated in the cosmology as the “main coamological principle”, i.e. that there is no preferred point/frame in the space, while matter around any point in the 3D space is observed as is distributed homothetically and isotropically. What really means that the cosmologists see the external through some double convey lens, and so measured distances values are really strange.

Really all isn’t, of course, so, including if the other main cosmological tenet that Matter was created at some “Big Bange” in some point is true – then this point is just the preferred point above.

Etc., more see the second link above, section “Cosmology” ; reDzennn comment, 6 passages , in/to phys.org article “Largest supernova dataset hints dark energy may be changing over time”

https://phys.org/news/2025-07-largest-supernova-dataset-hints-dark.html

- is quite relevant in this case.

Cheers