AetherCosPlay Aberration or Starlight

Work in progress

Overview

On 2026-06-26 on the Earth Awakenings Discord server Piezo, MCToon, Locksmith, Geo, and Brenda had this conversation about stellar aberration, Bradley's equation, and Airy's failure (transcript: Aries failure) during Hey Flerfs! Give Evidence (watch).

Discord conversation

Speakers: Piezo, MCToon, Locksmith, Geo, Brenda — see excerpt for roles.

Source: Livestream video; timestamps in section headers link to the video.

Context: Ether theory → stellar aberration pivot (3:43:03)

Speaker	Quote
Piezo	The "a field" also known as the vector potential in Maxwell's equations is the aether.
MCToon	That's it.
MCToon	And and and how how does so how does that negate how does that negate aberration of starlight and the color shift of starlight?
Piezo	So if you want to just start rattling things off one by one, this conversation is going to take forever. But what you asked was right, remember your original question, what are its predictions? And I said, okay, well here is the mathematical description of it that gives all the predictions.
Piezo	And now you're like pivoting to let's talk about stellar aberration and all this other stuff.
MCToon	Yeah, you you it needs to be consistent with those loop.
Piezo	It has to be consistent with all of those things though.

Stellar aberration vs. experiments (3:43:51)

Speaker	Quote
Piezo	Stellar aberration is not even consistent with experiments.
MCToon	Yes, it is.
Piezo	Uh not Aries failure.
MCToon	Aries failure was not testing for aberration.
Locksmith	It's a stationary geocentric observation. Anyways, a aberration is not a geocentric stationary observation.
Locksmith	Where do you take the measurements from
MCToon	the moving earth as as it confirmed that the earth is moving
Locksmith	So, it's geocentric then, right?
MCToon	No, you're you're assume putting the cart before the horse there, buddy. You're just you're just affirming the consequent.

James Bradley's equation (3:44:24)

Speaker	Quote
Piezo	Brad Bradley's equation Bradley's equation does not correctly predict what will happen if you vary one of the two velocities. It only has two input variables.
MCToon	Yeah?
Piezo	So if you if you vary one of those variables, then the angle should change and it didn't. That's the important part of invoking
MCToon	when was wait when was when did we vary the rotate the the the linear speed of the Earth around the sun?
Piezo	We didn't we varied the other variable which is the speed of that the light's moving through the telescope.
MCToon	Ah, yes. But special relativity deals with that just fine. So I don't know what your problem is.
Piezo	No, it doesn't.

Doing the math — Franco, Wikipedia, arcseconds (3:45:03)

Speaker	Quote
MCToon	Oh, no it doesn't. There you go. You're smarter than 120 years of of people that actually study this. Got it.
Piezo	If you you can you can take either either the publicly available equations straight off of Wikipedia or you can take the equations that we had Franco the CERN physicist write out and do a seven or eight page PowerPoint presentation on for us. Take either of those two equation sets and plug all the variables in and you'll get either 15 or 28 arcsec and his measurement was 20. So
MCToon	all right, I'd love to see that.
Piezo	Yeah. I mean, you can go on Alan has it on his website or he can send it to you personally if you want it. All right.
Locksmith	So, you're saying it matches the stationary telescope prediction?
Piezo	No, I'm saying that the math I'm saying that the I'm saying that the math if you use special relativity and you and you do it with, you know, the index of refraction for water and you plug all the numbers in, depending on which model you use, whether you use the plane wave model or whether you use the like uh photon model, you'll get either 15 arcseconds or 28 arcsec.
MCToon	the plane wave model or the photon model. What are these?
Piezo	Well, it's the emission theory and the wave theory of light. There's two different theories for light, right? You can treat it as a wave or a particle.
Piezo	So, either depending on which one you use, you'll either get uh 15 arcsec once you put water in the telescope or you'll get 28.
Piezo	And Franco did the math for 15. And if you use the other model that's on Wikipedia, you'll get 28, 27, 28. The answer is 20 as to what he measured. It did not change when you put water in it.
Piezo	That's the only thing you can't have. It has to change one of the other two. You can't have the angle not change. That's the one thing you can't have. That's what he measured.
MCToon	I don't think that's the actual answer, but okay. I'll have to look at that.
Brenda	Did we give up on tests of flat Earth?

Challenge to reproduce the calculation (3:47:06)

Speaker	Quote
MCToon	Yes. Yeah, that that was discarded a while ago. So, I do have uh it's coming up on 2 o'clock here and I got a bunch of super chats to read out. So, I won't uh I won't uh bore the uh Geo server here with that.
Geo	All right. Yeah, if you're going to read those and wrap up your show. But, uh I just wanted to say I don't I mean, nobody gave up on any of those tests. I don't know what you mean. Just in the conversation.
MCToon	Yeah, the conversation.
Piezo	You should make a follow-up video, mcune, where you where you do the math force failure. You can get the equations like they're on Wikipedia or where we can give you the Franco's presentation if you want both models and you can just plug the numbers in and see what it spits out. It's not going to spit out 20. I can tell you that. You should do a follow-up for your viewers.
MCToon	Sure.
Brenda	Did you decide on a test? Did you decide?
Piezo	So everybody can see so everybody can see what the velocity of light is in the water frame or in the sun frame, right? you get.
MCToon	So, yeah, Brenda, no test was agreed on.

Space Audits (Alan) and Franco Ligabue sources

In the debate, Piezo said the equations and Franco's presentation are on Alan's website — the site is Space Audits.

Alan's Space Audits site

• Space Audits — main Obsidian Publish site
• Airy's Experiment and Relativity (Ligabue 2025) — slide-by-slide breakdown of Franco Ligabue's 14-slide presentation on stellar aberration and Airy's water telescope (airy_relativity-1.pdf, 2025). This is the material Piezo described as Franco's "seven or eight page PowerPoint."
• Airy 1871 — On a supposed alteration in aberration — Alan's annotated version of George Airy's original paper, with links to related historical sources and to the Ligabue presentation.

Alan's site also references a planned 7-part "Response to Franco" rebuttal and a null-hypothesis page on aberration in air vs. water; those pages are linked from the Airy notes but were not published (404) as of June 2026.

Arcseconds in the Ligabue slides (for cross-checking Piezo's 15″ / 20″ / 28″ challenge): vacuum aberration β ≈ 20″; water angle in the telescope frame θ₂ = −β/n ≈ −15″ (plane-wave / Franco's model); wave-packet angle in the Sun frame θ′₂ ≈ 12″. Ligabue argues the observable Airy measured remains the vacuum angle β, not the internal water angle.

Franco Ligabue — public profiles

Franco Ligabue is an associate professor of experimental physics at the Scuola Normale Superiore (Pisa, Italy), a long-time CERN collaborator (ALEPH at LEP; CMS at the LHC), matching Piezo's description of "Franco the CERN physicist."

• SNS faculty profile (English)
• SNS faculty profile (Italian)
• ORCID: 0000-0002-1549-7107
• INSPIRE-HEP author record (F.Ligabue.1; CMS, ALEPH)
• Google Scholar profile
• University of Palermo publication index (ORCID-linked)
• Vanlett profile (@ilbue63)
• LinkedIn profile

TruthNerds response

In the comments section of that video, TruthNerds wrote:

A flat Earther found a formula which he doesn't understand and put some numbers in it. When has that ever happened before! (Warning, long post … see Brandolini's Law)

Anyway, Geo claims that Alan calculated the expected stellar aberration in Airy's failure experiment and that it doesn't match SR. By plugging in different light speeds, apparently. 😂

Ok, insider joke? I'll elaborate.

Let's first look at what Geo means by Bradley's formula. The classical formula is derived assuming that light propagates as a wave with a given speed in a stationary medium, aka aether, and the application of Newtonian mechanics.

It is θ - arctan(sin θ / (v/c + cos θ)) where θ is the angle of movement relative to the viewing direction, v is speed and c is the speed of light.

Then there's the relativistic formula, which is θ - 2 arctan(sqrt((1-v/c)/(1+v/c)) * tan(θ/2)). The relativistic formula reduces to the classical formula for v << c. Furthermore, for θ = 90° and v<<c, both reduce to v/c (in radians) as an approximation.

Ok, first, let's do some calculations, plain 90° aberration with Earth's average orbital speed gives about 0.0996 mrad (about 20.5 arcseconds) both for the classical and for the relativistic formula. It really makes no difference at those speeds!

Now, what did Alan presumably do to model Airy's experiment? Changing θ makes no sense, we want to keep that constant for comparability. Changing v makes no sense because Earth's speed wouldn't change. So he must've modified c. And that is hilarious!

Why? Well, for how Bradley's formula was derived, it would make sense because it is originally based on the assumption of a wave propagating through the aether. Slower wave propagation would thus affect the aberration angle.

But it doesn't make any sense to vary c in the relativistic formula! The relativistic formula is not derived from any assumption about a wave propagating through a fixed medium, it is based on the Lorentz transformation and the postulates of Special Relativity:

1. The laws of physics are the same in all inertial frames.
2. The speed of light in a vacuum (denoted c) is the same for all observers.

The speed of light to plug into the relativistic formula is always that same c, it has nothing to do with wave propagation in a medium. The formula follows from a coordinate transform in 4D spacetime. I.e. it is derived geometrically. It doesn't care about whether the light goes through a vacuum, air, water, glass or what have you.

Alan is once again debunking himself: If (classical) aether theory were correct, then Airy's experiment should have detected a change in aberration angle consistent with Bradley's formula (using different c).

Airy did not detect such a change, which is entirely consistent with SR. Alan therefore must straw man SR and misapply the relativistic formula in order to try and discredit it.

PS

The speed of light is actually the same in all media if you take the front velocity of a light pulse. That might also be called the speed of causality. What changes in water is the phase velocity. While this is very important for some optical effects, namely refraction, it is irrelevant for the derivation of the relativistic aberration formula.

PPS

Why do we still use the classical formula? It is simpler and a good approximation for non-relativistic speeds. However, we now know to also only use constant c in it. Then the formula's original derivation becomes invalid, but it remains valid as a numerical approximation. (It can be independently derived as an approximation of the SR formula.)