Biggest 3D map of the universe ready, 47 million galaxies mapped

In a stunning milestone for science, astronomers have just finished the biggest 3D map of the universe ever created.
The cherry on top is the fact that they wrapped up the long, intricate process a full year early.
The project, called DESI, offers an unprecedented look at how galaxies and stars are spread across space and time, promising fresh clues about one of cosmology’s biggest puzzles. The mystery behind the force is called dark energy.
It sits on the Nicholas U Mayall 4-metre telescope at Kitt Peak National Observatory in Arizona, US. DESI is a super-smart camera with 5,000 tiny fiberoptic eyes that lock onto distant objects every 20 minutes.
Starting in May 2021, it spent five years collecting light from galaxies, the glowing hearts of faraway galaxies called quasars, and stars.
The result of the long, tedious endeavour is now a map of more than 47 million galaxies and quasars, which beat the original goal of 34 million. Also mapped were around 20 million stars.
The map covers 14,000 square degrees of sky, roughly one-third of the entire celestial dome. By studying how their light has stretched over billions of years, the map traces cosmic history back 11 billion years.
Most people know the universe is expanding after the Big Bang.
But about 25 years ago, scientists discovered something surprising. They discovered that this expansion is speeding up and the driver of the acceleration is dark energy, an invisible force that makes up roughly 70 percent of the universe.
DESI’s map can now help scientists and researchers understand dark energy better by letting them measure how galaxies clustered together at different times.
Early data from the first three years already hinted that dark energy might not be constant, that it could be changing as the universe ages.
The full five-year dataset, which contains six times more objects than all earlier surveys combined, will test that idea more precisely and help predict the universe’s ultimate fate.
Despite achieving this remarkable feat, the instrument is not planning to stop. DESI plans to keep observing through 2028, expanding the map by another 20 percent and filling in tricky areas near the Milky Way.
Scientists expect the first big results on dark energy in 2027, with more discoveries rolling out soon after.
“This moment feels like sitting on the edge of my seat,” said NSF NOIRLab astronomer Stephanie Juneau.