Analysis of nearly 3,000 supernovas points to possible change in dark energy
A group of researchers analyzed a catalog of nearly 3,000 Type Ia supernovas. The data indicate that dark energy, which is associated with the accelerated expansion of the Universe, may change over time, Space.com reports.
A unified observation catalog
The team combined three decades of astronomical observations into a single consistent system. It compared supernova data with other cosmological measurements, including relic radiation from the Big Bang and information on the distribution of galaxies in space.
Team member Ryan Camilleri of the University of Queensland said that the updated analysis provided more evidence that dark energy may change over time. This differs from the standard cosmological model, which assumes that dark energy is constant and unchanging.
Supernovas as cosmic signposts
Type Ia supernovas occur when a white dwarf in a close binary system accumulates matter from a companion star and exceeds the Chandrasekhar limit. Such explosions have sufficiently uniform brightness, so astronomers use them as “standard candles” to measure cosmic distances through the redshift of light.
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When compiling the catalog, the researchers accounted for differences between observations from different telescopes, the effects of cosmic dust, galaxy masses, and gravitational lensing. The latter means the distortion and amplification of light by massive objects along its path to Earth.
DES and DESI data
The new catalog supplements earlier hints of dark energy variability obtained through the Dark Energy Survey, as well as results from the Dark Energy Spectroscopic Instrument released in 2024. According to Davis, the new compilation and DESI data are independent measurements that showed possible deviations from the model of unchanging dark energy, although the directions of these deviations differ somewhat.
In the future, the catalog is planned to be supplemented with observations from the Dark Energy Bedrock All-Sky Supernova program, which detects hundreds of additional nearby supernovas. The results of the work are available in the arXiv repository.
