u/nkinnan

At first I was wondering whether a "pancake" or "cylinder" of equal mass would be more effective at a distance. Then I went down the rabbit hole of halbach arrays, etc. At the end of the day I still don't have an answer. The objective of course is to be able to affect things at as large a distance as possible. Stated another way, to minimize field line divergence.

Technically I have a practical goal: to have as large a region as possible with minimal change in field strength (minimal field line divergence) at a particular strength. See, I've built a magnetic levitation "toy" with plates of pyrolytic graphite (a diamagnetic material), with a small magnet between them, and a large magnet above at an adjustable distance. This allows the small magnet to passively float without any electronics, but the vertical distance over which this works is quite small and the plates must be very close together. I want to increase the size of the "sweet spot" by having minimal field line divergence at a strength that pulls up on the small magnet with an equal force to gravity. A larger magnet placed further away only goes so far before becoming legitimately frightening (and expensive! plus I don't know what shape I should be buying or if it matters) and I'd like to have it single-ended rather than placing a magnet both above and below the plates which would also help.

The toy thing is just an aside though, it's also just an interesting physics question to me, and one that I've wondered about for a long time.

My exposure to this concept is via pop-sci youtubers, and so I have to wonder. Does anyone actually believe that the one-way and two-way speeds are different? Or is this just something to hook viewers with, by making them feel smart for understanding it, while being ultimately pointless?

It seems "obviously" true to me, both that it is technically correct that we can not prove their equivalence, and that the one-way and two-way speed of light is the same.

While there is no proof that they are the same, there is equally no reason to think that there would be disagreement. Here I would simply assert Occam's Razor.

So, what is the consensus within the scientific community? Does the idea have any merit, or is it just a self-licking philosophical ice-cream cone? Worth bringing up for highlighting the importance of proof in the scientific process and of questioning assumptions, but ultimately a bit ridiculous as an example?

Edit: My question is not about the benefit of questioning assumptions or the importance of the scientific method. Those are, in my view, self-evident.

Edit: Occam's Razor states that all else being equal, the simplest explanation is the most likely. A non-isotropic speed of light would be very complicated. This is not a question of intuition.