Dark energy surveys complete major observational milestones

Major astronomical surveys have reached significant observational milestones in the study of dark energy and the expansion of the universe.

The Dark Energy Spectroscopic Instrument (DESI) has completed its five-year observing campaign using the Mayall Telescope. The survey recorded spectra for over 47 million galaxies and quasars, alongside approximately 20 million stars in the Milky Way. While the data provides a three-dimensional map of cosmic history, researchers expect the first major results from the full five-year survey to be released in 2027. Previous DESI findings suggested dark energy might change over time, though this has not yet definitively challenged the standard cosmological model.

Separately, the Dark Energy Survey (DES), an international collaboration involving 35 institutions, has concluded a six-year analysis. Utilizing the Dark Energy Camera (DECam) in Chile, the project documented 669 million galaxies and thousands of supernovae. The findings strongly support the standard cosmological model, suggesting that dark energy acts as a stable cosmological constant. This research, supported by technical contributions from Argonne National Laboratory, provides a foundation for upcoming projects such as the Legacy Survey of Space and Time (LSST) at the Vera C. Rubin Observatory.