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Timm 07.11.19 08:58

Planck evidence for a closed Universe and a possible crisis for cosmology
 
https://www.nature.com/articles/s415...ivescience.com

Planck evidence for a closed Universe and a possible crisis for cosmology

Eleonora Di Valentino1, Alessandro Melchiorri2* and Joseph Silk3,4,5

The recent Planck Legacy 2018 release has confirmed the presence of an enhanced lensing amplitude in cosmic microwave background power spectra compared with that predicted in the standard Λ cold dark matter model, where Λ is the cosmological constant. A closed Universe can provide a physical explanation for this effect, with the Planck cosmic microwave background spectra now preferring a positive curvature at more than the 99% confidence level. Here, we further investigate the evidence for a closed Universe from Planck, showing that positive curvature naturally explains the anomalous lensing amplitude, and demonstrating that it also removes a well-known tension in the Planck dataset concerning the values of cosmological param-eters derived at different angular scales. We show that since the Planck power spectra prefer a closed Universe, discordances higher than generally estimated arise for most of the local cosmological observables, including baryon acoustic oscillations. The assumption of a flat Universe could therefore mask a cosmological crisis where disparate observed properties of the Universe appear to be mutually inconsistent. Future measurements are needed to clarify whether the observed discordances are due to undetected systematics, or to new physics or simply are a statistical fluctuation.

Wir leben krisenhaften Zeiten. Erst die Hubble Krise und dann auch noch Universum geschlossen. Vielleicht hängt ja auch beides zusammen oder - abwarten - beides bestätigt sich nicht.

Bernhard 08.11.19 08:09

AW: Planck evidence for a closed Universe and a possible crisis for cosmology
 
Herr Senf hat den Preprint dazu gefunden:

https://arxiv.org/abs/1911.02087

Timm 08.11.19 09:05

AW: Planck evidence for a closed Universe and a possible crisis for cosmology
 
The recent Planck Legacy 2018 release has confirmed the presence of an enhanced lensing amplitude in CMB power spectra compared to that predicted in the standard ΛCDM model. A closed universe can provide a physical explanation for this effect, with the Planck CMB spectra now preferring a positive curvature at more than 99% C.L. Here we further investigate the evidence for a closed universe from Planck, showing that positive curvature naturally explains the anomalous lensing amplitude and demonstrating that it also removes a well-known tension within the Planck data set concerning the values of cosmological parameters derived at different angular scales. We show that since the Planck power spectra prefer a closed universe, discordances higher than generally estimated arise for most of the local cosmological observables, including BAO. The assumption of a flat universe could, therefore, mask a cosmological crisis where disparate observed properties of the Universe appear to be mutually inconsistent. Future measurements are needed to clarify whether the observed discordances are due to undetected systematics, or to new physics, or simply are a statistical fluctuation.

S. die OP.


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