It took five years to build this cosmic map, but it’s already a challenge for Einstein.

Scientists using dark energy spectroscopy instruments have completed a five-year survey of the sky, mapping the universe beyond their original goals and asking new questions about the forces driving the expansion of the universe.

dark energy spectrometer known as Digihas completed its first five years of research, providing the most detailed three-dimensional map of the universe ever assembled. The instrument, mounted on the 4-meter Nicholas U. Mayall Telescope at Kitt Peak National Observatory in Arizona, has cataloged more than one location. 47 million galaxies and quasars, 13 million 20 million stars will be observed, more than the project originally planned. This dataset represents six times as many cosmological measurements of astronomical objects as all previous surveys combined.

The completion marks an important milestone in the broader effort to understand dark energy, a poorly understood force thought to be accelerating the expansion of the universe. Researchers have tracked how galaxies clustered in the past compared to the present to roughly trace that influence. 11 billion The history of the universe over several years. A complete analysis of the five-year dataset is expected to yield the first comprehensive dark energy results in 2027.

How DESI built the map

The device works by capturing light through the tip. 5,000 optical fibersEach is repositioned by a small robotic arm as the telescope sweeps successive areas of the sky. Each fiber collects light from an individual galaxy and sends it to a spectrometer, which separates the light into its constituent wavelengths. These spectra allow researchers to calculate each galaxy’s distance from Earth, allowing them to construct vast three-dimensional structures.

According to DESI Collaborative Project Scientist David Schlegel of Lawrence Berkeley National Laboratory, the study exceeded expectations due to a combination of steady technology improvements and minimal downtime. “We all know more about robots and motors than we did 10 years ago.” Schlegel said.Downtime is close to zeroMichael Levi, a Berkeley Lab scientist and lead researcher on the collaboration, said the device’s performance was better than expected and called the pace at which the team conducted the study “astounding.”

The completed map visualizes the large-scale structure of the universe: dense filaments of galaxies and galaxy clusters that come together under gravity and are separated by vast, relatively empty voids. Each point in the map represents one galaxy.

Dark energy results and future developments

DESI was designed to test whether dark energy behaves as a fixed object. cosmological constantan idea incorporated into Albert Einstein’s theory of general relativity. Early data from the first three years of the instrument suggest that the acceleration of the universe may have changed over time, indicating that dark energy may be variable rather than constant. Although the statistical significance of this result may still be low enough to preclude further scrutiny, it has led theorists to explore alternative frameworks.

Bhuvnesh Jain, a cosmologist at the University of Pennsylvania, said DESI’s interim findings have generated considerable interest. “It rules out the simplest physical description of dark energy and states that Occam’s razor may not be deployed prematurely.” he said.

Schlegel estimates that it will probably be about a year before the team can determine what the completed map reveals about dark energy. Meanwhile, DESI continues to collect data in more difficult-to-observe regions of the sky, including lower regions of the southern sky. 15 million Add galaxies to the dataset.

The study reflects contributions from a wide range of experts, instrument builders, software engineers, technicians, observatory staff, and many young researchers, said Dr. Stephanie Juneau, NSF’s NOIRLab project director. “Ultimately, we are doing this for all of humanity to better understand the universe and its ultimate destiny.” she said.This moment feels like sitting on the edge of your seat while analyzing a new map, after finding hints that dark energy may deviate from the stationary and change its fate” Collaboration publication schedule some additional papers The first three years of data will be available later this year, with the entire five-year dataset entering the processing pipeline.