A recent study from Duke University has added new information to the ongoing question regarding the Universe's expansion, often referred to as the "Hubble tension." This issue arises from a discrepancy that scientists measuring the Universe’s expansion rate (the Hubble constant) are getting. There are different results depending on the method used. The new findings suggest that our current understanding of cosmology may need adjustments to account for a faster-than-expected expansion.

To calculate the Hubble constant, astronomers rely on a method called the cosmic distance ladder, which means various techniques are used to determine how far away celestial objects are. In this study, researchers used data from the Dark Energy Spectroscopic Instrument (DESI), which collects observations of over 100,000 galaxies every night. 

 

 

 

 

 

 

 

 

 

 

 

(Left) The locations of the SNe Ia identified to be in the Coma cluster (yellow stars) and the galaxies identified to be in the Coma group as from the full S24Coma group catalog (light gray circles), the S24FP sample (dark blue circles), and the T15Coma group catalog (light blue circles). The center of the cluster is marked in red. The positions of the SNe are listed in Table1. (Right) For the rectangular box on the left, a colored image of that sky area with the SNe within that location marked (Credit: D. Scolnic et al. 2025, The Hubble Tension in Our Own Backyard: DESI and the Nearness of the Coma Cluster, ApJL979L9).

 

 

A key part of their approach involved accurately measuring the distance to the Coma Cluster, a massive collection of galaxies about 320 million light-years away. They accomplished this by analyzing the brightness patterns of 12 Type Ia supernovae—exploding stars that have a well-known characteristic named luminosity, making them useful for measuring cosmic distances.

The researchers determined a Hubble constant value of 76.5 kilometers per second per megaparsec. This value aligns with other recent measurements of the nearby Universe but remains at a stanstill with predictions based on observations of the more distant cosmos. Lead author Dan Scolnic pointed out that this growing inconsistency may indicate deeper issues with the standard cosmological model. Therefore, the study also highlights the need for a fresh look at current theories to resolve the contradictions in our understanding of how fast the Universe is expanding.