Supernova analysis suggests dark energy may vary over time
A unified analysis of 2,884 Type Ia supernovae reveals evidence that dark energy may not be constant, challenging a core assumption of the standard cosmological model.
A massive analysis of 2,884 exploding stars challenges the assumption that dark energy is constant, suggesting it may change over time. The study, the largest collection of Type Ia supernovae ever compiled, did not confirm the standard cosmological model and instead adds fresh evidence for a dynamic dark energy.
The research combines three decades of observations. It incorporates historical measurements and findings from the 2024 Dark Energy Survey (DES). The team had to link data from different telescopes and correct for cosmic dust and galaxy mass, both of which can alter the light that reaches Earth. They even included subtler effects like gravitational lensing, the bending of light by massive objects. The supernova data were then combined with other cosmic measurements, including relic light from the Big Bang and maps of galaxy distributions.
Global collaboration enables unprecedented supernova dataset
The work was led by scientists at the University of Queensland’s School of Mathematics and Physics, with PhD candidate Ryan Camilleri as a key contributor. It involved an international collaboration from multiple surveys, including the Dark Energy Survey, Foundation Supernova Survey, PanStarrs I, and the Sloan Digital Sky Survey. The dataset was created by revisiting older observations using updated analytical methods to improve consistency.
Ryan Camilleri said the project rebuilt those decades of observations into one consistent framework. "We’ve rebuilt 3 decades of astronomical observations into a single, consistent framework," he noted. The effort sets a new international standard for supernova cosmology and builds on the work of hundreds of astronomers worldwide.
Key findings and future expansion plans
The standard model of cosmology treats dark energy as a fixed, unchanging property of the universe. The new analysis offers a hint that this may be incorrect. The finding is not yet a proof, but it pushes against a central assumption. The Dark Energy Spectroscopic Instrument (DESI) had also found hints of variation in dark energy in its surveys of relic sound waves. These two datasets are completely independent and do not show exactly the same departure from the standard model.
Professor Tamara Davis noted that the 2024 DES supernova data first showed hints of time-varying dark energy. The findings may help reconcile gravity with quantum physics, a major unresolved problem in theoretical physics. The cosmology findings and a companion set of host galaxy mass measurements are available on the preprint server arXiv.
The researchers plan to expand the dataset as more observations arrive. Future data will come from the Dark Energy Bedrock All-Sky Supernova program (DEBASS), which is identifying hundreds of supernovae closer to Earth.
