All of Einstein's Relativity is rubbish. His spacetime is rubbish (actually i don’t think that he believed in spacetime either).
https://www.sbs.com.au/topics/science/fundamentals/article/2016/01/08/why-einsteins-general-relativity-such-popular-target-cranks
I started to take a closer look at Einstein in 2011, & i see that my science section in my computer now has 65,000 files, mainly aether stuff & Einsteinian stuff. But i didn’t take much interest in electricity nor in Einstein's connections to electricity & Maxwell.
Anyhow, all of Einstein's Relativity is rubbish. One thing that did impress me is Einstein's prediction of what is now known as
Shapiro Delay.
Einstein said that light slows near mass, proven by Shapiro in the early 60's. Light bends when passing the Sun.
Similarly my
electons bend when passing Cu, or at least they try to bend, they
hug the Cu, whilst propagating at almost the speed of light (well they would, they are light, ie electons are photons). Einstein's explanation for the slowing of light near mass is of course flawed, as is all of his stuff.
Similarly electons bend when passing a nucleus, ie they
hug the nucleus, & propagate around the nucleus, what we call orbiting the nucleus. And we call the orbiting electons
electrons.
When electons hug a wire they have a negative charge. Hence their hugging will be affected by free (surface) electrons (ie conduction electrons), on the wire. Electons will tend to be repelled. At the same time they will be attracted to the Cu protons near the surface. Electons (1) will i suppose push free-ish electrons along on the wire (2) & in the wire (3). Hence we have (3) kinds of electricity (on/on/in)(propagation/flow/drift).
Recently Erik Margan wrote a paper where he showed that Shapiro Delay explained Einstein's doubled Newtonian bending of light near the Sun. I contacted Erik & told him that Dicke had already done that in the 50's (ie before it was called Shapiro Delay)(Shapiro discovered Shapiro Delay in the 60's). I also told Erik about my electon theory for electricity (ie that electons hug Cu because of Shapiro Delay), but Erik was not impressed with my electons.
But seeing as HuronKing is interested in things Einsteinian, i will introduce some anti-Einsteinian stuff. Namely the
aetherwind.
Veritasium's gedanken says that his answer is (d), ie 1/c. But we have to allow for the aetherwind.
We have measured the
background aetherwind blowing through Earth to be 500 km/s blowing south to north approx 20 deg off Earth's axis. Hence the speed of em radiation (through the aether) in Veritasium's gedanken is c plus or minus up to c/600 depending on the orientation of his wires. The em would radiate at tween 599c/600 & 601c/600.
Hence if his wires were 600 mm apart he could calculate the correct delay by simply saying that the effective gap was 599 mm (if his em radiation had a tailwind) or 601 mm (if a headwind). And the direction of the background aetherwind would have other effects on em fields.
The speed of electricity along a TL would depend on the orientation relative to the background aetherwind, & on the time of day (which would affect orientation)(the effect of Earth's spin being minor, only 0.14 km/s), & on time of year (the Earth orbits the Sun at 30 km/s). The time taken to send electricity in one direction along a 600 km TL could vary by in effect by 2 km compared to the other direction.
And then we might want to allow for the
local aetherwind, which has to be added to the background aetherwind. The local aetherwind blows into the Earth at 11.2 km/s, & a component blows towards the Sun at 42 km/s (& a little blows to the Moon).
These little complications will start to show up as we enter the present ultra accurate age of science.
And the old silly Einsteinian factoids will fall one by one.
STR is krapp -- & GTR is mostly krapp.
We are presently in the Einsteinian Dark Age of science -- but the times they are a-changin'.
The aether will return -- it never left.