Dark energy as breathing and pressure

Standard cosmology accounts for the accelerating expansion of the universe with a dark energy term, the cosmological constant Λ. RSI proposes that what is observed as acceleration is not a new kind of energy but a balance of two effects of the medium.

The first is the history of the medium's breathing (Chapter VI). Galaxies are not receding: redshift compares the rhythm of matter when the light left with the rhythm of matter now, and the same history shapes how bright distant supernovae appear. Christof Wetterich (2013) showed that the standard history, including the supernova measurements read as acceleration, can be rewritten exactly as one in which the universe does not expand while the masses of particles and the Planck mass grow together; in his model the growth is driven by a scalar field, and RSI proposes the breathing medium in its place. Because the medium is incompressible, this share is the same in every direction.

The second comes from the circulation. The Eternal Consonance circulates through the torus in a closed loop, outward from the Source at its center toward the edge and back. If the circulation were steady, the outward flow would slow as it spreads and its pressure would rise. RSI proposes instead that the engine at the Still Core is currently speeding the circulation up. When a flow is being sped up, every part of the medium has to be pushed forward, and only pressure can push it, so pressure falls, on the whole, along the direction of flow around the loop. It is raised again chiefly at the engine, with smaller local rises at the jets of galactic black holes. Galaxies are not carried by the medium, which pushes nothing along. They fall down these gradients, and on the return side that fall is the bulk flow toward the Great Attractor.

The two shares leave different fingerprints. The breathing changes everywhere at once, so its effect on supernova distances is the same in every direction. The engine's gradient has a direction, so its share would appear as a difference in supernova distances between directions on the sky. Some studies report such a dependence, roughly aligned with the CMB dipole, while others find none, so the question is open. Measuring it would measure how the balance divides.

Because the breathing and the engine's output both change over the cycle, this account implies that dark energy is not exactly constant. In 2025 the DESI survey reported that its data, combined with other measurements, favor dark energy that weakens over time, at about 2.8 to 4.2 standard deviations depending on the supernova sample used; a later recalibration of one supernova sample lowered the highest figure to 3.2. That is suggestive, not settled, and a constant is not ruled out. If it holds up, it is consistent with a breathing medium.

This also marks a clean difference from standard cosmology. There, dark energy keeps the same density while space grows, so its total keeps growing, and General Relativity has no universal law of energy conservation to forbid it. RSI proposes that energy is conserved locally at every moment and, counting the energy of the breathing of the medium's folds, in total at every moment too, the breathing lending energy to matter and light within a cycle and taking it back over the full cycle (Chapter VI): light keeps its energy in flight, the breathing trades energy with matter over the cycle, and the engine's share is paid for by matter unzipping at the core, at a rate RSI must show fits the amount of matter we observe.

Several steps are still open. RSI must derive the history of the breathing and show that it reproduces the measured supernova distances. It must show that the engine's push outweighs the rise in pressure the spreading Exhale would otherwise produce, and that the energy released at the Still Core can supply it. And it must express the quantities in the equation through the medium's properties, so that the two shares together give the observed dark-energy density of about 5 × 10⁻¹⁰ joules per cubic meter.