Astronomers have released the largest two-dimensional map of the universe ever built. The map charts nearly 4 billion stars, galaxies, and other objects across roughly 75% of the sky. Anyone can explore it for free through the Legacy Survey Sky Viewer.
A decade of sky surveys
The map came out of the DESI Legacy Imaging Surveys, a project that combined data from three telescopes. Two are in the United States and one is in Chile. Over about a decade, the telescopes captured hundreds of thousands of images in multiple colors.
Researchers stitched those images into a single digital atlas. The result covers an area of sky so large that it would take a lifetime to look at every object by eye. The team released the data in stages, and this version is the most complete yet.
What the map can do
The atlas is more than a pretty picture. Scientists can use it to hunt for gravitational lenses, where massive objects bend the light from distant galaxies. They can search for supernovae and other exploding stars. They can also study the large-scale structure of the universe, which holds clues about dark matter and dark energy.
Other telescopes are already using the map as a guide. When a new mission needs to know what lies in a patch of sky, it can look it up in the atlas first. That saves time and makes observations more efficient.
Science for everyone
The team behind the map made a point of keeping it public. The Legacy Survey Sky Viewer lets anyone zoom in on galaxies, nebulae, and star fields from a web browser. Astronomers hope the open data will draw new people into the field and speed up discoveries.
"The universe is big enough for everyone to explore," one researcher said. "Now the map is too."