A dark energy driven by star formation

Rolf Landauer showed that "information is physical" with every bit equivalent to a small amount of energy proportional to temperature. The Landauer equivalent energy of information carried, or represented by matter, effectively provides an information dark energy (IDE). Many objects in the universe, ranging in size from stars to galaxy clusters, have temperatures that vary in relation to the square root of the object mass.

In a study published in Entropy, Professor Paul Gough at the University of Sussex shows that combining this relation with a survey of star formation measurements yields a star-formation-driven IDE with a history that matches the recent Dark Energy Spectrograph Instrument (DESI) results (see image above). The significant overlap between the IDE prediction and actual DESI measurement is evidence for a star-formation-driven IDE source of a phantom dark energy (increasing energy density).

Up to now, the consensus ΛCDM model has been successful, although there are still no satisfactory accounts for either of the two main components, Λ and cold dark matter (CDM). As the latest DESI result shows, Λ is located outside of the measured dark energy likelihood region (see image above); it is worth also considering alternative explanations, like IDE.

Besides the good fit of IDE to the measured dark energy history, IDE also has a significant total universe energy approaching the 10⁷⁰ Joules mc² equivalent energy of the universe, 10⁵³ kg of baryons.

An IDE source of dark energy can overcome many of the problems and tensions of the standard model. For example, IDE accounting for observed dark energy effects would enable Λ to take the more likely value of zero, and resolve the cosmological constant problem.

Increasing star formation, with increasing IDE, leads to our present dark-energy-dominated epoch. Rising star formation also enhanced the likelihood of intelligent beings evolving to discover the accelerating expansion of the universe. It is therefore not surprising that we are living in the dark-energy-dominated epoch, and the "Why now?" cosmological coincidence problem is also effectively resolved.

As the universe's mass density fell sharply with increasing universe volume, IDE rose rapidly with star formation. This combination resulted in the sudden appearance of dark energy in the late universe when IDE energy density overtook the mass energy density.

Several theoretical studies have shown that such a sudden turn-on of dark energy can resolve the present tensions in both the Hubble constant, H₀, and the σ₈ matter fluctuation parameter. These tensions in H₀ and σ₈ arise because values measured today are found to differ significantly from values predicted when using the standard ΛCDM model to extrapolate from the early universe.

IDE is also expected to account for at least some effects previously attributed to dark matter. The General Theory of Relativity tells us space–time will be distorted by any accumulation of energy, in whatever form. The IDE associated with matter in galaxies will therefore add to the space-time distortion caused directly by matter. Having the same effect as an extra unseen matter component, IDE would then be difficult to distinguish from dark matter.

Two examples of gravitational effects that could be more easily accounted for by IDE are given here. In many galaxies, the measured dark-matter-attributed effects have been shown to have their location fully specified by baryon location. While this is difficult to reconcile with ΛCDM, it is clearly compatible with IDE.

The recent JWST observations of very early emerging massive galaxies and early clusters of galaxies require a nonlinear accelerating structure formation. Again, while this is difficult for the linear hierarchical galaxy formation of ΛCDM, we expect such a nonlinear effect with IDE as the local attraction increases with star formation.

The standard ΛCDM model assumes that the accelerating expansion of the universe will continue ad infinitum, leading to an eventual "heat death" or "big chill." But IDE tells a different story. Star formation is in the process of reaching a peak and IDE will eventually start decreasing, leading to a return to a matter-dominated epoch with a decelerating expansion rate. Then, perhaps, the universe will end in a "big crunch," or continue forever as an "oscillating" or "bouncing" universe.

Gough summarizes, "While, universe-wide, IDE is repulsive as a dark energy, locally, IDE is attractive like a dark matter." The table above indicates the extent to which IDE may explain some of our observations of the dark side.

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Paul Gough is Emeritus Professor of Space Science, University of Sussex. Gough's research interests include cosmology, astrophysics, space science, and geophysics.