Compare · Before the Universe

Simple Big Bounce vs Conformal Cyclic Cosmology (CCC)

Cyclic & Bouncing Cosmologies· within family

	Simple Big Bounce Speculative	Conformal Cyclic Cosmology (CCC) Speculative
Proposed	various	2005
Key figures	Various authors	Roger Penrose
In one sentence	The Simple Big Bounce treats our universe as the rebound of a previously contracting universe, with the Big Bang as the minimum-size moment of that transition.	A previous "aeon" existed. Its conformally smooth heat-death geometry became our Big Bang.
Predictions	The universe did not begin at a singularity but at a finite bounce point Some matter or radiation from the previous contracting phase may be detectable Specific signatures in the CMB depend on the bounce mechanism	Concentric CMB rings (Hawking points) Smooth conformal transition, no [[singularity]] Massless [[dark matter]] required at aeon boundary
Where it breaks	No direct observational evidence of a contracting pre-Big Bang phase Different bounce mechanisms make different predictions, making the framework difficult to test as a single theory Some bounce mechanisms require fine-tuning to avoid sending the universe into a singularity anyway	Independent analyses find rings consistent with noise Requires massless dark matter, not established Community consensus is largely skeptical Bodnia et al. (2024) find no statistically significant low-variance circles or Hawking points in Planck/WMAP data using a ResNet18 ML pipeline, contradicting earlier Gurzadyan-Penrose claims.
Key unresolved problem	The too-many-options problem: the big bounce idea is really a grab bag of different bounce mechanisms, each predicting something different, so it cannot be tested as one theory until you pick a specific version.	The missing fingerprint: other teams cannot find the predicted Hawking-point rings, faint circles in the cosmic microwave background, leaving CCC's one big observational claim statistically unsupported.
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Simple Big Bounce

various · Speculative

Conformal Cyclic Cosmology (CCC)

2005 · Speculative

Proposed

various

2005

Key figures

Various authors

Roger Penrose

In one sentence

The Simple Big Bounce treats our universe as the rebound of a previously contracting universe, with the Big Bang as the minimum-size moment of that transition.

A previous "aeon" existed. Its conformally smooth heat-death geometry became our Big Bang.

Predictions

The universe did not begin at a singularity but at a finite bounce point
Some matter or radiation from the previous contracting phase may be detectable
Specific signatures in the CMB depend on the bounce mechanism

Concentric CMB rings (Hawking points)
Smooth conformal transition, no [[singularity]]
Massless [[dark matter]] required at aeon boundary

Where it breaks

No direct observational evidence of a contracting pre-Big Bang phase
Different bounce mechanisms make different predictions, making the framework difficult to test as a single theory
Some bounce mechanisms require fine-tuning to avoid sending the universe into a singularity anyway

Independent analyses find rings consistent with noise
Requires massless dark matter, not established
Community consensus is largely skeptical
Bodnia et al. (2024) find no statistically significant low-variance circles or Hawking points in Planck/WMAP data using a ResNet18 ML pipeline, contradicting earlier Gurzadyan-Penrose claims.

Key unresolved problem

The too-many-options problem: the big bounce idea is really a grab bag of different bounce mechanisms, each predicting something different, so it cannot be tested as one theory until you pick a specific version.

The missing fingerprint: other teams cannot find the predicted Hawking-point rings, faint circles in the cosmic microwave background, leaving CCC's one big observational claim statistically unsupported.

Reader vote

No votes yet