Recent content by timmdeeg

Instead, looking for negligible tidal effects one would consider areas far away from gravitational centers like stars and galaxies. Within a galaxy cluster there might be such areas and if being connected these could result to scales of 4 to 15 MPc. Perhaps that's what the authors refer to...

So, if you say "that it (the equivalence principle) only applies locally, over a scale where spacetime curvature is negligible and an individual patch of spacetime on that scale can be considered to be flat" does it mean that tidal effects are negligible? From this point of view I would assume...

Such scales refer to Galaxy cluster which as I understand it don't feel isotropic expansion. If we consider them as spacetime patches containing galaxies as point particles, why then can't we assume flat spacetime within them?

Why can't one simply argue that in an infinite expanding universe the distance between any two comoving objects grows without limit?

Unexpectedly for me this seems a crucial point! PeterDonis and Ibix, many thanks for enlightening comments.

So ##t## now isn't special. Now both models predict the same "amount" of accelerated expansion whereby the temperature ratio is 1100. If true independent of ##t## wouldn't this mean that in the far future both models predict the same "amount" of accelerated expansion whereby the temperature...

Good point. And the values of ##t## might depend on where one lives, in a wall or in a void.

Yes, but isn't it astonishing that otherwise much different models predict this very same ratio of scale factors? Of course they have to, so its not a coincidence (wrong wording).

What I meant, saying "coincidence" : There are two models (one established and the other one speculative) which explain the measured accelerated expansion today (using the same Supernovae data) much differently, but nevertheless agree that the universe has expanded by a factor of 1100 since...

In "Supernovae evidence for foundational change to cosmological models" they say Physically, it is motivated by an extension of Einstein’s Strong Equivalence Principle to cosmological averages at small scales (∼ 4 – 15 Mpc) where perturbations to average isotropic expansion and average...

Thanks, got it.

"Supernovae evidence for foundational change to cosmological models" https://arxiv.org/pdf/2412.15143 The paper claims: We compare the standard homogeneous cosmological model, i.e., spatially flat ΛCDM, and the timescape cosmology which invokes backreaction of inhomogeneities. Timescape, while...

Thanks for clarifying, this I've been missing even though I'm watching chess games online sometimes.

I'm still not clear with this. Wouldn't the assumption that "a particle may not exist beyond measurements/observations/interactions" be disproved in case the particle feels gravity beyond measurements ... what in principle should be measurable in case it isn't obviously true anyway?

Mentioning GR I refer to "doesn't exist" in the quote in #59 obviously wrongly thinking that this relates to RQM.