What was the Big Bang?
There was no Big Bang, in the sense of a first moment when everything began. Winding the universe back to a beginning needs a global clock running for the whole universe, and there is none to turn back. Every clock is local, and time is the order in which observers read one another's records. Spacetime is not fundamental either. It is built from those records, so there is no container that could shrink to a point. What the records do show is a hot, dense era at the far end of a reconstruction from evidence held today, such as the microwave glow, light-element ratios, galaxy spectra and supernova catalogs. The name Big Bang marks where that trail of records goes dark. Ripples on the microwave sky are slightly stronger at large angles, and OPH puts that tilt at 0.966021. Planck measured 0.9649 ± 0.0042, a 2025 combined analysis reads 0.9743 ± 0.0034, and the prediction fails if the tilt lands well away from 0.966021.
Also in Chapter 39: Why Is a Bacterium Freer Than an Atom?.
This answer comes from OPH, Observer Patch Holography. OPH is a rigorous, consistent and complete description of the unified, self-creating computational Universe we inhabit. Its consistency is machine-checked: the fixed point at its core is constructed explicitly, and a theory with a model contains no contradiction.
To understand OPH and check every step yourself, start with the free book Reverse Engineering Reality. It builds the theory from the ground up, and the OPH Notebook answers your questions while you read.
read the free bookask the notebookor ask sage:read appendix a: Eighteen Questionswatch a universe make its own particles