Supernova study finds further signs that dark energy could change
A compilation covering 2,884 stellar explosions adds evidence against a constant dark energy model, though separate measurements suggest different departures.
Dark energy might evolve rather than remain constant, according to researchers who assembled measurements of 2,884 Type Ia supernovae. The international group, led by University of Queensland scientists, said its findings add to evidence questioning how standard cosmology describes the force behind the Universe’s accelerating expansion.
The work combines earlier observations with results published in 2024 by the Dark Energy Survey (DES). Type Ia supernovae, which occur when white dwarf stars explode, let astronomers gauge cosmic distances and investigate changes in the expansion of the Universe.
PhD candidate Ryan Camilleri said the researchers also used measurements of radiation remaining from the Big Bang and maps showing galaxy distribution. To make the supernova records comparable, they applied newer analytical techniques to older observations, accounting for telescope differences, dust, galaxy masses and gravitational lensing, which bends and magnifies light.
Astrophysicist Professor Tamara Davis said the compilation shows a departure from the standard model, but not quite in the direction indicated by the earlier DES findings. She said separate observations by the Dark Energy Spectroscopic Instrument (DESI), based on ancient sound waves, have also suggested variation in dark energy. The measurements do not agree on the precise departure.
Further additions to the dataset are planned, including observations from the Dark Energy Bedrock All-Sky Supernova program (DEBASS). That effort is finding hundreds of explosions nearer to Earth than the supernovae observed by DES.
