Astronomers analyzing a catalog of nearly 3,000 type Ia supernovas report that dark energy is changing over time rather than remaining fixed, challenging the standard model of cosmology and aligning with recent findings from the Dark Energy Spectroscopic Instrument.
A massive catalog of cosmic explosions is challenging the foundational assumption of modern cosmology. Researchers studying nearly 3,000 type Ia supernovas have found fresh evidence that dark energy, the mysterious force driving the accelerated expansion of the universe, is not constant as long believed.
Rebuilding Decades of Astronomical Observations Into a Single Framework
The new compilation draws on decades of work to standardize data from multiple telescopes, accounting for galaxy mass, cosmic dust, and gravitational lensing. By tracking white dwarfs that exploded after stripping material from binary companion stars, the team created a uniform set of standard candles to measure cosmic distances.
We've rebuilt 3 decades of astronomical observations into a single, consistent framework,
team member Ryan Camilleri of the University of Queensland said in a statement.
Camilleri noted that researchers also incorporated relic light from the Big Bang and large-scale galaxy distribution maps. These refinements allowed scientists to detect deviations from the standard model of cosmology, which treats dark energy as a fixed property of space.
Extensive work has been done to link observations from different telescopes with different capacities and take into account issues such as cosmic dust and galaxy mass which can affect the light coming from a supernova,
Camilleri explained. We also incorporated more subtle effects such as gravitational lensing, which is the bending and magnification of light around large objects as it travels from a supernova to Earth.
Aligning With Independent Surveys and Independent Measurements
The supernova findings directly support earlier results published in 2024 by the Dark Energy Spectroscopic Instrument (DESI), which analyzed relic sound waves from the early universe and similarly pointed toward a weakening influence of dark energy over time.
While both the Dark Energy Survey (DES) compilation and DESI point away from a static universe, researchers note that the respective deviations tilt in slightly different directions. Even so, the convergence of two independent techniques provides growing pressure against standard cosmological assumptions.
Our supernova data from DES in 2024 first showed hints that dark energy may be time-varying, and this new compilation also sees a deviation from the standard model, although in a slightly different direction,
Davis said. Similarly, results from DESI found hints of variations in dark energy in its surveys of relic sound waves from the early universe.
So, two completely independent measurements have found hints of time variation in dark energy, challenging the standard model that dark energy doesn't change, Davis added
Expanding the Hunt for Dark Energy With the Nancy Grace Roman Space Telescope
As astronomers push to confirm whether dark energy is truly evolving, hardware capabilities are expanding. NASA recently launched the $4.3 billion Nancy Grace Roman Space Telescope aboard a SpaceX Falcon Heavy rocket from the Kennedy Space Center in Florida.
Originally developed as a spy telescope for the National Reconnaissance Office before being transferred to NASA, the observatory features a field of view at least 100 times larger than the Hubble Space Telescope. Project scientists estimate that a one-month survey of the Milky Way by the Roman telescope would require roughly a century using Hubble.
Roman project scientist Julie McHenry noted that one month of observations to survey the Milky Way galaxy would take about a century with Hubble. Furthermore, Roman scientist Vanessa Bailey described the extreme technical hurdles of capturing direct images of planets orbiting distant stars, comparing it to trying to see a firefly next to a lighthouse hundreds of miles away and noting that engineers use a coronagraph inside the camera to block the light source.
The newly launched telescope will hunt for additional type Ia supernovas and use gravitational microlensing to discover distant planets. Currently traveling toward its parking spot at the Lagrange point roughly a million miles from Earth, the observatory faces a checkout period before its first operational images arrive, including spending the next 45 days checking out instruments and the 45 days after that checking out the telescope itself.
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