No singularity, just a bounce. A previous universe contracted, then sprang into ours.
Loop Quantum Big Bounce
Quantum geometry prevents the singularity. Our Bang is the bounce of a contracting predecessor.
Looping ambient scene for Cyclic & Bouncing Cosmologies. There is no absolute beginning. Our universe is the latest phase in an eternal cycle. Variants disagree on the mechanism: a conformal transition (Penrose), a quantum bounce (LQC), a brane collision (Ekpyrotic), or a dilaton-driven bounce (Pre-Big Bang).
§1 · The claim, in one sentence
A previous contracting universe bounced, quantum geometry prevented the collapse from becoming a singularity.
§2 · Why it might be true
Loop Quantum Cosmology applies the quantized spacetime geometry of Loop Quantum Gravity to the early universe. At classical extremes, when density approaches the Planck scale (the tiny scale where quantum effects on gravity become unavoidable), the fabric of space and time cannot be treated as smooth. Quantum geometry takes over, and predicts that infinitely high density cannot occur.
Instead of collapsing into a singularity, a contracting universe reaches a maximum density and "bounces" back into expansion. Our Big Bang was not the absolute beginning, it was the bounce point.
The family stance
A previous cycle, aeon, contracting phase, or alternate-brane state existed before our universe. The "before" is a physically connected predecessor, not nothing or another arena.
§2.5 · Evidence
- Mathematically consistent with LQG framework
- Singularity-free without ad hoc assumptions
§3 · What you'd need to test it
- Quantum bounce at Planck density
- Modified CMB power spectrum at large angular scales
- Pre-Bang contracting universe phase
§4 · Where it breaks
- Effects only at Planck scale, not currently testable
- LQG itself is incomplete
- CMB corrections sub-dominant to cosmic variance
Go deeper
In LQC, the classical FRW equations get quantum corrections at high density. The modified Friedmann equation includes a term -ρ²/ρ_crit, where ρ_crit ~ 0.41ρ_Planck.
When density approaches ρ_crit, the Hubble parameter goes to zero and reverses sign, this is the bounce. The bounce happens at densities ~10⁻³ ρ_Planck, comfortably within the regime where LQC corrections are valid.
▸§5 · Who built it, and when(3 sources, 3 established)
- EstablishedBojowald (2001). 'Absence of a singularity in loop quantum cosmology.' Phys. Rev. Lett. 86, 5227772 citations
- EstablishedAshtekar et al. (2006). 'Quantum nature of the big bang.' Phys. Rev. Lett. 96, 141301845 citations
- EstablishedAshtekar & Singh (2011). 'Loop quantum cosmology: a status report.' Class. Quantum Grav. 28, 2130011,207 citations
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