bigbounce

Visual timeline

Cosmic timeline

From the parent universe through the bounce to SPHEREx 2028 and beyond — one typographic line, no cards.

  1. ∞ — ?

    Parent universe

    A previous universe contracts under gravity. Density increases toward Planck scale (~10⁹³ g/cm³).

  2. t → 0⁻

    Contraction phase

    Matter-dominated contraction. Perturbations grow, imprinting f_NL = -35/16 on the bispectrum. PBH seeds form.

  3. t = 0

    The bounce

    Torsion (or quantum gravity) prevents a singularity. Density reaches maximum but stays finite. Expansion begins.

  4. 10⁻³⁶ s

    Post-bounce expansion

    Universe expands rapidly. No inflation needed — the contraction phase already solved the horizon and flatness problems.

  5. 3 min

    Nucleosynthesis

    Light elements form (H, He, Li). Identical to standard cosmology. ΔNeff ≈ 0 confirmed by our MCMC.

  6. 380,000 yr

    CMB release

    Universe becomes transparent. CMB carries bounce imprint: f_NL, birefringence β = 0.27°, spectral index.

  7. ~1 Gyr

    First galaxies

    Galaxies form from primordial perturbations. BigBounce's historical DESI pipeline records are unreconciled and do not establish a high-redshift population or a bounce connection; the anomaly flagship is being rebuilt.

  8. 9.8 Gyr

    Dark energy onset

    Dark energy begins dominating expansion. Whether w(z) crosses -1 (quintom-B behavior) is treated theoretically in our program; external DESI DR2 (Adame et al.) reports 2.8-4.2σ for w-crossing depending on dataset combination. Our own DESI DR2 w0wa chain (Paper 1B) gives w_pivot = -0.952 ± 0.019, +2.5σ from -1.

  9. 13.8 Gyr

    Now (2026)

    BigBounce is organized around three research tracks (A: bounce vs. inflation flagship, B: the ECH Note closed line, C: DESI data products). Track A now reports three honest nulls (PTA, PBH, high-z PNG) plus one reachable-but-unseparable LSS channel; final author review remains separate from endorsement, submission, and independent peer review. Readiness is tracked live on /status.

  10. 2028

    SPHEREx launch

    SPHERExis a relevant future probe of primordial non-Gaussianity. Whether the paper's conditional f_NL = -35/16 result maps to a survey-level test depends on the stated bounce-transmission and covariance assumptions; it would not by itself prove a unique bounce origin.

  11. ~2032

    LiteBIRD

    JAXA's LiteBIRD will measure birefringence to ~0.03°. Tests β = 0.27° prediction at ~9σ.

  12. ~2035

    LISA

    ESA's LISA will detect induced gravitational waves from PBH formation. Tests the bounce GW spectrum directly.