Why is the universe expanding?
OPH explores expansion as a change in the density of records used to reconstruct spacetime. An event order says what can influence what; an additional count supplies a candidate volume measure. If the same pattern of causal relations contains a changing density of physical events, the effective geometry can have a changing scale. Clocks and light signals inside that geometry would register expansion and redshift. This is a proposed physical identification, not the claim that merely storing more data makes a universe expand. The construction must produce the relevant record history, its ruler and clock comparisons, and the observed expansion law together. The fixed-horizon-capacity branch supplies a candidate cosmological constant; it does not by itself select the complete cosmological history.
See also What is dark energy?, Why was the early universe so uniform and nearly spatially flat?, Does OPH explain the Hubble tension?
Sources: Observer-screen synchronization as a candidate inflation-free branch; Observer spacetime and the conditional Einstein reconstruction
Also in Chapter 29: Why 1/137, and Why Is There a Limit to What the Universe Can Remember?, Chapter 35: What Is Anything Made Of?, Appendix A: Eighteen Questions.
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 chapter 25: Why Does Gravity Look Like Geometry?watch a universe make its own particles