Will the Big Bang repeat?
Sabine Hossenfelder・2 minutes read
Roger Penrose proposes conformal cyclic cosmology (CCC), involving eons starting with a big bang and ending without a big crunch, utilizing conformal rescaling to transition between cycles. Penrose aims to address the second law of thermodynamics through quantifying entropy in the gravitational field, suggesting the existence of "erebons" as potential dark matter particles in a universe with patterns from previous eons.
Insights
- Roger Penrose's conformal cyclic cosmology (CCC) proposes cycles of the universe called eons, starting with a big bang but not ending with a big crunch, utilizing conformal rescaling to transition between eons.
- Penrose aims to address the second law of thermodynamics by quantifying entropy in the gravitational field, suggesting the existence of a new particle called "erebons" that may make up dark matter, but the physical implications and ability to solve the past hypothesis of CCC remain subjects of debate.
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Recent questions
What is conformal cyclic cosmology (CCC)?
Conformal cyclic cosmology (CCC) is Roger Penrose's theory about the universe's beginning and end. It involves cycles called eons, starting with a big bang but not ending with a big crunch.
What is the key concept in CCC?
The key concept in CCC is conformal rescaling, which involves stretching or shrinking the universe while maintaining relative angles.
How does Penrose address the second law of thermodynamics in CCC?
Penrose aims to address the second law of thermodynamics in CCC by quantifying entropy in the gravitational field.
What is the Weyl Curvature Hypothesis?
The Weyl Curvature Hypothesis posits that the universe's entropy was initially small and increased over time.
What are "erebons" in CCC?
"Erebons" are a new particle suggested by Penrose that may make up dark matter in CCC.
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Summary
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Penrose's Conformal Cyclic Cosmology: Universe's Cyclical Theory
- Roger Penrose's idea for the universe's beginning and end is called conformal cyclic cosmology (CCC).
- CCC involves cycles called eons, starting with a big bang but not ending with a big crunch.
- Conformal rescaling is a key concept in CCC, involving stretching or shrinking while maintaining relative angles.
- Penrose aims to address the second law of thermodynamics by quantifying entropy in the gravitational field.
- The Weyl Curvature Hypothesis posits that the universe's entropy was initially small and increased over time.
- Conformal rescaling is used to transition from one eon to the next in CCC.
- The universe must approach conformal invariance for the rescaling to work, potentially involving the removal of massive particles.
- Gravitational waves from previous eons can leave patterns in the cosmic microwave background, like Hawking points.
- Penrose suggests the existence of a new particle called "erebons" that may make up dark matter.
- While CCC presents interesting mathematical puzzles, its physical implications and ability to solve the past hypothesis remain debatable.
