The Legacy Imaging Surveys from the Dark Energy Spectroscopic Instrument (DESI) have created the most extensive 2D map of the Universe, built on 13 years of observations using three of the most powerful telescopes globally. This initiative supports astronomers in their exploration of dark matter and dark energy, and the map is accessible online for everyone.
The project’s scale is beyond imagination. The vast 2D map of the Universe consists of 5.6 trillion pixels, resulting from 263,407 exposures that captured nearly four billion objects, which range from nearby asteroids to black holes located at great distances. A preliminary version released in 2023 has already been referenced in over 1,800 scientific publications.
This research has also analyzed the spectrum of 21 million stars and 48 million galaxies. Together with the redshifts of galaxies, this information contributes to the largest three-dimensional map of the Universe completed to date. The images, featuring both visible light and near-infrared, encompass roughly 75% of the sky, as reported by IFL Science.
What does the largest 2D map of the Universe include?
Dr. Arjun Dey from NOIRLab clarified that the absent region primarily corresponds to the plane of the Milky Way, where the dense concentration of stars, dust, and gas complicates the observation of the far-off Universe. “That’s why we primarily examine areas outside the disk. The ‘missing’ sections on our maps relate to the region covering the Milky Way’s plane,” said Dey.
Even though around 95% of the point sources on the map are likely to be stars, they do not represent the central focus of the project. DESI primarily targets distant galaxies to piece together the history of the Universe’s expansion. “DESI aims to decipher the enigmatic dark energy, which we suspect could be responsible for the accelerating expansion of the Universe,” Dey explained. The instrument tracks how cosmic expansion has evolved over the past roughly 11-12 billion years.
Data from DESI has already indicated that dark energy may be evolving, and its influence on the acceleration of the Universe’s expansion could be diminishing.
A deeper insight into the Universe
The map can be examined through the Legacy Survey Sky Viewer, allowing users to zoom and search for specific objects. Researchers can also detect gravitational lenses or transient phenomena like supernovae. For those seeking more information, a comprehensive catalog of DESI Legacy Survey data is available.
Upcoming observatories, including Vera C. Rubin and Nancy Grace Roman, are likely to create more detailed maps, but the data from DESI will remain indispensable. By comparing observations from various instruments, astronomers will gain a better understanding of the Universe and harness the unique benefits of each telescope.
