Recent content by ChrisF

That's a fair and important distinction. You're right — within ΛCDM, H(t) is time-varying and Λ is not, so any relationship built on H₀ specifically is epoch-dependent, not fundamental. Milgrom noted the numerical coincidence but the problem you're identifying — why now? — is real and known in...

Fair correction — the multiple definitions are understood tools for encoding different observational relationships, not a flaw in the model. I stated that poorly. The sharper version of the point is this: extracting any of those observables from raw data — flux, angular size, redshift —...

Primarily two: first, that the (1+z) factors applied to photon flux across the rungs of the distance ladder are correctly accounted for — luminosity distance and angular diameter distance carry different powers of (1+z) and K-corrections require assuming a spectral model. Second, and more...

The measured present value — Milgrom's original observation is a₀ ~ cH₀ using the observed expansion rate. The connection to Λ is then one step indirect: in flat ΛCDM, Λ = 3H_Λ²/c² where H_Λ = H₀√Ω_Λ ≈ 0.84 H₀. So a₀ ~ cH₀ implies a₀ ~ c√(Λ/3) to within that same factor. The coincidence holds...

Fair technical point — to be precise, the Standard Model is the SU(3)×SU(2)×U(1) gauge theory covering three forces. Gravity sits outside it, which is exactly why it's listed separately and why this thread exists. The four fundamental interactions of nature — strong, weak, electromagnetic...

For you weirdoguy, we'll do it Barney style. The Standard Model has four forces. Three of them speak the same language. One doesn't. Electromagnetism, the weak force, and the strong force are all described by the same mathematical grammar called gauge theory. Think of three departments in...

● The closeness of a₀ and Λ-derived quantities isn't coincidence — it's been noted explicitly in the literature. Milgrom himself pointed out that a₀ ~ cH₀, which connects MOND's critical acceleration directly to the cosmological expansion rate. Since in ΛCDM the cosmological constant satisfies...

A fair challenge, and worth being precise about. In Gaussian or natural units ε₀ and μ₀ don't appear explicitly — they are absorbed into c and the impedance of free space Z₀. But the physical content they represent doesn't disappear with the unit choice. The vacuum still has a propagation...

Re: The wrong turn of string theory: our world is SUSY at low energies Congratulations to arivero on the EPJC publication — the sBootstrap having a peer-reviewed home gives this discussion a firmer foundation to build from. The combinatorial case for three generations is genuinely...

Re: Dynamical gravity from RG flow of the CFT boundary in AdS/CFT duality? The Sheikh-Jabbari paper is genuinely interesting because it's attacking the right problem from a novel angle — and you've laid out the obstacles clearly. The Weinberg-Witten workaround via AdS/CFT is elegant on...

Re: Constructing a purely gravitational, nonlocal action that reproduces CDM cosmology Deffayet and Woodard are being admirably honest in that conclusion, which makes the paper worth taking seriously even if the result is uncomfortable. The key admission is right there: their model...

Re: whether to couple or not Hossenfelder's framing cuts to the heart of why hybrid approaches keep hitting this wall. The dilemma is real and it's structural, not just a tuning problem. Here's why it can't be escaped within the superfluid dark matter framework: GW170817 showed that...

Re: All possible models to explain the hierarchy problem? The short answer is: not quite, and the reason why is instructive. Nnaturalness works because it imposes a specific constraint — the SM should not be atypical among the N sectors. This is doing real physical work. The reheaton...

Re: Information or Particle First? Good question — and the answer the Standard Model actually gives might surprise you. In QFT, neither information nor particles are the most fundamental entities. Quantum fields are. Particles are not objects — they are excitations of underlying fields. An...

Great question - and I genuinely wish I could contribute. I'd love to discuss it here on Physics Forums because honestly, this is where these conversations should happen. I understand not allowing it in the homework section, but there should be nothing wrong with discussing theoretical physics...