Entropic increase is the underlying cause of a fifth force of Nature

The kinetic energy of our Universe’s unaccreted and unbound baryons constitutes a force of Nature, orthogonal to the other four known forces. The Cosmological Principle is applied at the time of last scattering to express the behavior of the Universe's then-monatomic baryons as a gaseous perfect fluid (GPF). Gravitational anisotropy was spatially negligible back then, and ranged within the time domain only, so the atoms had Euclidean straight-line trajectories. Their collective elastic behavior can be expressed with the gas laws. Application of these laws to this unbound GPF gives a scalar and repulsive entropic force field. Local volume increase is an essential component of its force. Universal density reduction was (and is) driven by thermal loss, attenuated by gravity, and later fed by thermal shock, streaming high-energy particles, and photon flux, all of which arose from within the accreted cosmic web of galaxies. Total energy was and is conserved, as the GPF's thermal loss converts to entropic energy gain. Differentially, this gain is kinetic energy. I will show that differential kinetic gain in the Universe is always at least twice that of gravity uptake from all forms of equivalent mass, if accreted matter is excluded. GPF and Friedmann Hubble flows become identical at a certain accretion fraction. This oral presentation will focus on a numeric treatment of the Hubble tension’s origin. If time permits, a conservative explanation of the ‘dark’ energy effect will be given.