Largest universe map ever: 47M galaxies cataloged
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- DESI completed its main five-year sky survey at Kitt Peak National Observatory in Arizona, cataloging 47 million galaxies and quasars — far exceeding the original target of 34 million
- David Schlegel at Lawrence Berkeley National Laboratory noted previous cosmic maps covered a total of just 5 million galaxies, making DESI's contribution roughly 10 times larger than everything that came before
- An earlier DESI dataset from 2024 suggested dark energy is weakening over time, rather than remaining constant as the standard model assumes
- If confirmed, weakening dark energy would challenge the lambda-CDM standard model of cosmology, which describes the force that makes up roughly 70% of the universe
- Full analysis of the dataset will take another year, and DESI will continue collecting data for at least 2.5 more years — with hopes of upgrades extending operations into the 2030s
- The current map spans 14,000 square degrees of sky, with plans to expand to 17,000; the full sky totals over 41,000 square degrees, much of it obscured by the Milky Way
Why it matters: DESI's full dataset needs another year of analysis before release, and the project will collect data for at least 2.5 more years. With this volume, astronomers can rigorously test the 2024 finding that dark energy (~70% of the universe) is weakening — a result that, if confirmed, would force revisions to the lambda-CDM model underpinning modern cosmology. Schlegel projected every observable galaxy within 10 billion light-years could be mapped by 2061 at the current pace.
