The Hubble tension, a long-standing issue in cosmology, refers to the discrepancy between measurements of the universe’s expansion rate using different methods. The standard model of cosmology, known as Lambda Cold Dark Matter (ΛCDM), predicts a specific value for the Hubble constant (H0). However, observations from the Cosmic Microwave Background (CMB) and standard candles like Cepheids and type Ia supernovae yield a different value, around 73 km/s/Mpc.
Researchers William Giarè, Miguel A. Sabogal, Rafael C. Nunes, and Eleonora Di Valentino have proposed an alternative model to explain this discrepancy: Interacting Dark Energy (IDE). In this model, dark energy and dark matter interact with each other, transferring energy and momentum between them. This interaction adds a new parameter to the ΛCDM model, which describes the amount of energy transferred.
Using Bayesian statistics, the authors analyzed data from the Planck mission, baryon acoustic oscillation (BAO) data from DESI, and supernova data from SH0ES. They found that their IDE model explains the data equally well as the ΛCDM model but pushes the Hubble constant towards higher values.
The study provides a significant overlap between the IDE model’s estimate of H0 and the supernova estimate from SH0ES. However, when combining all three datasets, the discrepancy with the supernova-derived H0 increases. The researchers note that to compensate for this effect, they would need to decrease the density of normal matter in the universe.
While the results are promising, there are still challenges to overcome before concluding that IDE resolves the Hubble tension fully. Nevertheless, this study highlights the importance of exploring new physics and models to better understand the complex nature of the universe.
Source: https://astrobites.org/2025/01/18/desi_ide_h0