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#timescape

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bananabob :tinoflag:

Can't remember if this was posted on Mastodon or I found it elsewhere but it sure is interesting and makes the brain hurt thinking about it all.

<< A competing theory to 'dark energy' suggests the universe has different time zones >>

I have always had a feeling that Dark Energy was not the answer. But what do I know, I barely got a physics 'O' Level in the UK.

cbc.ca/radio/quirks/dark-energ

CBCA competing theory to 'dark energy' suggests the universe has different time zones | CBC RadioNew measurements of a certain type of supernova seems to indicate that our expanding universe isn't accelerating at all, negating any need to invoke a mysterious 'dark energy' to explain supernovae observations.
#CBCRadio#DarkEnergy#TimeScape
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Futuro Prossimo :verified:

E se l'accelerazione dell'espansione cosmica fosse solo un'illusione ottica? Una nuova analisi di 1500 supernovae suggerisce che il modello del "timescape cosmology", con le sue bolle di spazio-tempo dal ritmo diverso, si adatta ai dati meglio del modello standard. Un colpo di scena cosmico che potrebbe riscrivere la storia dell'universo e aprire una nuova era della cosmologia. Il dibattito è aperto.

#Cosmologia #teorie #Timescape #Cosmology #Universo #Cosmo

futuroprossimo.it/2025/01/lacc

L’accelerazione dell’universo è un’illusione? Le teorie alternative
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ellohir

Parece que el último tema candente en el mundo de la astrofísica es la teoría del Timescape como alternativa a la Energía Oscura. Básicamente: si dejamos de tratar al universo como homogéneo en cuanto a densidad de masa-energía, las observaciones con corrimiento al rojo que explican la aceleración de la expansión del universo se pueden explicar como consecuencia de la transición de la luz por zonas de espaciotiempo de alta y baja densidad de masa-energía. La expansión del universo puede no estar acelerando, por lo que puede que el futuro del universo no sea la expansión hasta el vacío eterno.

Me parece super interesante, a ver qué réplicas obtiene este estudio en la comunidad científica.

youtube.com/watch?v=hE_xLGgZzF

#astrofísica#timescape#LambdaCDM
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rexi

universetoday.com/170261/new-s

…argues…#darkenergy would violate principle of equivalence (which) equates inertial energy and gravitational energy; no way to distinguish cosmic expansion as a real effect…#Timescape model argues that the Universe can’t be homogeneous in time…within the gravitational well of a galactic cluster, clocks would run more slowly…Over the billions of years…this difference would build up, creating a variance…that would give the appearance of cosmic expansion.

Universe Today · New Study of Supernovae Data Suggests That Dark Energy is an IllusionDark energy is central to the standard model of cosmology, but the Timescape model suggests dark matter doesn't exist.
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Boud

"Cosmological foundations revisited with Pantheon+"

Lane, Seifert, Ridden-Harper, Wagner & Wiltshire

arxiv.org/abs/2311.01438

This article compares the #TimeScape inhomogeneous cosmological model to an updated supernovae Type1a set.

#Reproducibility proposed based on
github.com/antosft/SNe-Pantheo

This is just hot off the press, I don't (yet?) have an opinion on it.

arXiv.orgCosmological foundations revisited with Pantheon+We reanalyse the Pantheon+ supernova catalogue to compare a cosmology with non-FLRW evolution, the "timescape cosmology", with the standard $Λ$CDM cosmology. To this end, we consider the Pantheon+ supernova catalogue, which is the largest available Type Ia supernova dataset for a geometric comparison between the two models. We construct a covariance matrix to be as independent of cosmology as possible, including independence from the FLRW geometry and peculiar velocity with respect to FLRW average evolution. Within this framework, which goes far beyond most other definitions of "model independence", we introduce new statistics to refine Type Ia supernova (SneIa) light-curve analysis. In addition to conventional galaxy correlation functions used to define the scale of statistical homogeneity we introduce empirical statistics which enables a refined analysis of the distribution biases of SneIa light-curve parameters $βc$ and $αx_1$. For lower redshifts, the Bayesian analysis highlights important features attributable to the increased number of low-redshift supernovae, the artefacts of model-dependent light-curve fitting and the cosmic structure through which we observe supernovae. This indicates the need for cosmology-independent data reduction to conduct a stronger investigation of the emergence of statistical homogeneity and to compare alternative cosmologies in light of recent challenges to the standard model. "Dark energy" is generally invoked as a place-holder for "new physics". Our from-first-principles reanalysis of the Pantheon+ catalogue supports future deeper studies of the interplay of matter and nonlinear spacetime geometry, in a data-driven setting. For the first time in 25 years, we find evidence that the Pantheon+ catalogue already contains such a wealth of data that with further reanalysis, a genuine "paradigm shift" may soon emerge. [Abridged]
#DarkEnergy#DarkEnergyAsAnArtefact
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