Modified Gravity Produces Non-Singular Cyclic Universe With 89 Gyr Period
A classical modification of gravity suffices to replace the Big Bang singularity with a cyclic bounce cosmology whose parameters are already bounded by existing data. The 89 Gyr cycle offers a concrete observational target that distinguishes it from Lambda-CDM without invoking quantum gravity.
The model replaces the Big Bang singularity with a finite-size bounce by allowing the gravitational potential to depart from Newtonian form only at unprobed cosmic distances. This produces an expansion history that transitions smoothly into a Lambda-CDM-like phase before eventual recollapse and repeat bounce, all within purely classical modified gravity without new microphysical fields.
Data from five independent probes jointly constrain the two new length-scale parameters, fixing the cycle period near 89 Gyr while keeping early-universe nucleosynthesis and CMB acoustic peaks intact. The framework subsumes many bounce scenarios under one testable parametrization, offering a route to distinguish cyclic models from standard cosmology via future large-scale structure measurements.
The chief limitation is that the work remains a preprint; no peer review has yet scrutinized the stability of the modified potential against solar-system or binary-pulsar tests at intermediate scales. A decisive strengthening would come from explicit forecasts for DESI and Euclid redshift-space distortions that could detect the predicted late-time deviation from Lambda-CDM growth within the next five years.
DESI: measurable deviation in f sigma_8 growth rate exceeding 3 percent from Lambda-CDM at z<0.5 by 2028 data release.
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2609.16015)
- [2]Supporting Source(https://arxiv.org/abs/1806.02340)