The largest 3D map of the universe has been completed and will help study dark energy

The DESI survey mapped more than 47 million galaxies and quasars, creating the most detailed 3D view yet of the structure and expansion of the universe.

Scientists have reached a major milestone in the effort to understand dark energy with the completion of observations in the full target region of the DESI (Dark Energy Spectroscopic Instrument) 3D map of the universe.

The project was completed ahead of schedule and the data produced far exceeded expectations. The resulting map is the most detailed, high-resolution, 3D view of the universe ever created. Researchers will use it to study dark energy, the mysterious force believed to make up about 70% of the universe.

Mapping 47 million galaxies and quasars

Over five years, DESI has collected data on more than 47 million galaxies and quasars, as well as 20 million stars. These observations have already provided important insights into the structure of the universe and its evolution over time, said Professor Paul Martini, who was involved in building DESI.

Overcoming difficulties during the survey

Despite an ambitious schedule, the team encountered several obstacles in completing the survey. One of the most significant disruptions occurred in 2022, when the Contreras fire knocked out power and internet access at the observatory for months. Those problems were eventually resolved and the project continued, said Ashley Ross, a scientist at DESI.

"We found creative solutions to solve unexpected problems, and the high-quality data we collected each night was used rigorously and reliably to obtain the exciting cosmological constraints that DESI is now known for," said Ross.

New data changes understanding of the universe

Now, with the completion of the full dataset, scientists have a powerful new resource for testing long-held ideas about the balance between dark energy and matter. These findings could significantly change how researchers understand the universe and its future.

DESI has collected data on six galaxies and quasars, more than all previous measurements combined. The team plans to start processing the complete data soon, with the first results expected in 2027.

Next observation phase until 2028

Although the initial mission is complete, DESI will continue to collect data until 2028. Future observations will expand to areas of the sky that are harder to study: Creating an even more detailed map could help scientists examine nearby objects like dwarf galaxies and stellar streams, and offer a clear picture of the formation and evolution of the universe, said Klaus Hunschied, a scientist at DESI. 

In the meantime, researchers will continue to refine measurements of dark energy using data from the first three years, and also improve how the telescope is used to support new discoveries.

"A larger survey would greatly improve our constraints on cosmological parameters and enhance the dark matter program," said Hunshid. "But these achievements are only possible because of the hard work of the operating team to advance the survey."

More of the topic in Hayadan:

• Hidden change in dark energy could rewrite the laws of physics
• Dark energy: a map hints at what it is - but deepens the dispute over the expansion rate of the universe
• Physicists fight counterfeiters
• More evidence supports the existence of dark energy
• An X-ray photograph of a galaxy cluster supports the existence of dark energy