The Sky Map With Four Billion Objects
Thirteen years of telescope exposures have become a 5.6-trillion-pixel map covering roughly three-quarters of the sky. Nearly four billion objects are now open for anyone to inspect.
The Discovery
The DESI Legacy Imaging Surveys team has released what [NSF NOIRLab describes as the largest 2D map of the Universe](https://noirlab.edu/public/news/noirlab2620/). The 5.6-trillion-pixel dataset catalogs nearly four billion celestial objects across roughly 75 percent of the sky.
It took 13 years and 263,407 telescope exposures to assemble. The combined surveys used the Dark Energy Camera on the Blanco telescope, the Mayall telescope, the Bok telescope, and years of infrared data from NASA's WISE mission.
What Makes It Strange
This is not a finished portrait of the cosmos. It is a gigantic hunting ground containing stars, galaxies, black holes, asteroids, supernovae, and gravitational lenses, including rare objects that have not been singled out yet.
The map looks through visible and near-infrared light at the extragalactic sky beyond the dust and stars of the Milky Way. Researchers and citizen scientists can inspect the public data through the Legacy Survey Sky Viewer and Astro Data Lab.
The Implications
The 2D map records where objects appear and how bright they look. DESI then measures selected objects at different wavelengths to calculate distance and build a three-dimensional view of cosmic structure.
That structure lets scientists trace galaxy clustering over time and test how dark energy has shaped the Universe's expansion. The map is an atlas, but its unresolved details are an invitation: billions of points are now waiting to be recognized.