Feb 23, 2023 11:54 PM
(This post was last modified: Feb 23, 2023 11:57 PM by C C.)
https://bigthink.com/starts-with-a-bang/...-big-bang/
KEY POINTS: The original Big Bang has since been modified to include an early inflationary phase, pushing whatever came before inflation to an unobservable place. When inflation ends, the hot Big Bang ensues, and we can see evidence from the final tiny fraction-of-a-second of inflation imprinted on our observable Universe. However, we can't see anything from before that time. Despite the assertions of one of the most famous living physicists, there's no evidence for a Universe prior to that.
EXCERPTS (Ethan Siegel): . . . Nobel Laureate Roger Penrose, although his work on General Relativity, black holes, and singularities in the 1960s and 1970s was absolutely Nobel-worthy, has spent a large amount of his efforts in recent years on a crusade to overthrow inflation: by promoting a vastly scientifically inferior alternative, his pet idea of a Conformal Cyclic Cosmology, or CCC.
The biggest predictive difference is that the CCC pretty much requires that an imprint of “the Universe before the Big Bang” show itself in both the Universe’s large-scale structure and in the cosmic microwave background: the Big Bang’s leftover glow. Contrariwise, inflation demands that anywhere inflation ends and a hot Big Bang arises must be causally disconnected from, and cannot interact with, any prior, current, or future such region. Our Universe exists with properties that are independent of any other.
The observations — first from COBE and WMAP, and more recently, from Planck — definitively place enormously tight constraints (to the limits of the data that exists) on any such structures. There are no bruises on our Universe; no repeating patterns; no concentric circles of irregular fluctuations; no Hawking points. When one analyzes the data properly, it is overwhelmingly clear that inflation is consistent with the data, and the CCC is quite clearly not... (MORE - missing details)
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Sabine Hossenfelder: Completely coincidentally, Paul Tod put a new paper about Conformal Cyclic Cosmology on the arXiv just a few days ago. Among other things, he addresses the point I mentioned in the video about the eon-to-eon feedback, though the brief answer seems to be no one really knows: https://arxiv.org/abs/2202.10864
Will the Big Bang repeat? (Conformal Cyclic Cosmology) ... https://youtu.be/Jl-iyuSw9KM
https://www.youtube-nocookie.com/embed/Jl-iyuSw9KM
KEY POINTS: The original Big Bang has since been modified to include an early inflationary phase, pushing whatever came before inflation to an unobservable place. When inflation ends, the hot Big Bang ensues, and we can see evidence from the final tiny fraction-of-a-second of inflation imprinted on our observable Universe. However, we can't see anything from before that time. Despite the assertions of one of the most famous living physicists, there's no evidence for a Universe prior to that.
EXCERPTS (Ethan Siegel): . . . Nobel Laureate Roger Penrose, although his work on General Relativity, black holes, and singularities in the 1960s and 1970s was absolutely Nobel-worthy, has spent a large amount of his efforts in recent years on a crusade to overthrow inflation: by promoting a vastly scientifically inferior alternative, his pet idea of a Conformal Cyclic Cosmology, or CCC.
The biggest predictive difference is that the CCC pretty much requires that an imprint of “the Universe before the Big Bang” show itself in both the Universe’s large-scale structure and in the cosmic microwave background: the Big Bang’s leftover glow. Contrariwise, inflation demands that anywhere inflation ends and a hot Big Bang arises must be causally disconnected from, and cannot interact with, any prior, current, or future such region. Our Universe exists with properties that are independent of any other.
The observations — first from COBE and WMAP, and more recently, from Planck — definitively place enormously tight constraints (to the limits of the data that exists) on any such structures. There are no bruises on our Universe; no repeating patterns; no concentric circles of irregular fluctuations; no Hawking points. When one analyzes the data properly, it is overwhelmingly clear that inflation is consistent with the data, and the CCC is quite clearly not... (MORE - missing details)
- - - - - - - -
Sabine Hossenfelder: Completely coincidentally, Paul Tod put a new paper about Conformal Cyclic Cosmology on the arXiv just a few days ago. Among other things, he addresses the point I mentioned in the video about the eon-to-eon feedback, though the brief answer seems to be no one really knows: https://arxiv.org/abs/2202.10864
Will the Big Bang repeat? (Conformal Cyclic Cosmology) ... https://youtu.be/Jl-iyuSw9KM