In a statement today, the DESI collaboration officially published the final results of the instrument’s first survey: a high-resolution 3D map of the universe spanning more than 11 billion years of cosmic history. Impressively, over five years DESI, based at Kitt Peak National Observatory in Arizona, collected cosmological data for “six times more galaxies and quasars than all previous measurements combined,” according to the release. Astronomers will use this dataset to study the effects of dark energy, a hypothetical force that drives the acceleration of the universe.
“DESI’s five-year survey has been a spectacular success,” DESI Director Michael Levy said in a statement. “We’re going to celebrate the completion of the original survey and then get to work churning through the data, as we’re all curious to see what new surprises await us.”
Very good
DESI recently made headlines in 2025, when the first batch of analyzes strongly indicated that dark energy changes over time. This contradicted traditional cosmological models, which maintained that dark energy was constant. While groundbreaking, the results were not technically “complete”, as the analysis was only based on the first three years of DESI data. Therefore, the final decision will have to wait until astronomers get the complete picture.
Well, the “whole picture” is now available. That said, the sheer volume of DESI data means scientists haven’t even completed studying the first batch, though the research team said the final dataset is already under investigation.
Additionally, it demonstrates DESI’s incredible potential in studying dark energy, which accounts for approximately 68.7% of the universe. Understanding how dark energy evolves has huge implications for how the universe evolves – and, most importantly, how it might end. We’ll likely hear more on this front once scientists have fully processed and analyzed the vast collection of data. So, stay tuned.
working overtime
To give quick observations, DESI is equipped with 5,000 fiber-optic “eyes” that allow it to capture detailed images of distant cosmic objects, equivalent to about 80 gigabytes of data each night. Then, it repeatedly visits the same area to record the full “footprint” of faint sky lights. Each data point is processed through ten spectrographs to determine its position, velocity, and chemical composition.
“There has been constant monitoring and intervention to make the whole thing go smoothly,” said Adam Myers, co-manager of DESI’s survey operations.
Overall, DESI finished Very Good at his work. As a result, the team added an entirely new side project, the “Bright-Time Survey”, in which DESI captured how light reflected from the Moon affects observations of faint, distant objects. In five years, DESI managed to cover about two-thirds of the northern lights sky.
in the unknown sky
Again, it is very likely that some important news regarding the nature of dark energy will be revealed soon. In the meantime, DESI will continue surveying the night sky until about 2028, when the instrument will focus on revisiting parts of the sky that the initial survey was not able to capture.
The team hopes the expanded map will help us understand other cosmic mysteries beyond dark energy, such as dark matter. But scientists also intend to gather clear data on nearby dwarf galaxies and things like stellar streams, bands of stars torn from smaller galaxies into the Milky Way. The sky is the limit—literally.
“We are now moving forward from our original plan,” Levy said. “We don’t know what we’ll find, but we think it’ll be pretty exciting.”
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