Jan 25, 2026
3 min read
An international project has found more accurate measurements that limit the range of possible models for the evolution of the universe.The results combine weak gravitational lensing and galaxy clustering and, for the first time, combine four different quantifiers of dark energy in one experiment.
Find new clues about the expansion of the universe
A global project has found the right parameters to limit the number of possible models of global development.The results combine weak lensing and galaxy clustering and for the first time combine four different measurements of dark energy in one experiment.
About a century ago, astronomers noticed that distant galaxies were moving away from us.In fact, the farther away a galaxy is, the faster it is receding.It provided the first substantial evidence that the universe is expanding.But the mechanism that regulates it is under investigation.
That's what the International Scientific Collaboration's Dark Energy Survey (DES) has been doing since 2013. Now, for the first time, it will publish two references that combine six years of data from gravitational lensing and galaxy clusters as techniques for measuring the expansion of the universe.
The paper, which compiles 18 scientific papers and is still awaiting peer review, also presents the first results of the combination of four different measurements of dark energy - baryonic acoustic oscillations (BAOs), type Ia supernovae, galaxy clusters and weak gravitational lensing - as suggested in the original DES concept 25 years ago.
The study provides new and accurate parameters that narrow the range of possible models of the universe's evolution.These measurements are more than twice the limit as those found in previous DES analyzes and are consistent with previous results.
How to measure dark energy
Because the universe is governed by gravity - the force that attracts matter - astronomers expected the expansion of the universe to slow down over time.
In 1998, two independent teams of cosmologists discovered using distant supernovae that the expansion of the universe was accelerating rather than slowing down.To explain these observationsThey suggest a new type of energy is responsible for driving this accelerated expansion.which is dark energy. Astronomers currently believe that dark energy accounts for approximately 70% of the mass-energy density of the universe.However, we know very little about him.
In the following years, scientists began to design experiments to study dark energy, including dark energy.Today, DES is an international collaboration of more than 400 astronomers and scientists from 35 institutions in 7 countries, led by the Fermi National Accelerator Laboratory of the US Department of Energy.
To study dark energy, the DES collaboration mapped a large, deep region of the sky between 2013 and 2019. The DES collaboration built the ultra-sensitive 570-megapixel digital DECam camera, which was installed on the US National Science Foundation's Interero Tolonic Foundation on the 4-meter Blanco telescope.
Over 758 nights over six years, the DES collaboration recorded data from 669 million galaxies billions of light-years away from Earth, covering one-eighth of the sky.The Spanish institutions have been part of the project since its inception and, in addition to essential collaboration in the design, construction, testing, installation and data collection of DECam, today they assume the main responsibility for the scientific use of the data.
"From our images, we can measure the shapes and subtle gravitational distortions of the galaxies, as well as their positions and distributions on the sky. But to interpret these measurements, we also need to know how far away the galaxies are, which we do from their colors, the distances at which the observations are measured using different Energy Village D filters," explains Dark.I calibration team.
Julia Giannini, head of the DES Redshifts Working Group and a researcher at ICE-CSIC in Barcelona, said: "In this analysis, we bring the distance calibration to an unprecedented level of precision, allowing us to reliably link the observed galaxy distribution to the physics of dark energy."
6 billion years of history
To obtain these new results, DES scientists developed extensive methods that use weak gravity to reconstruct the distribution of matter in the universe.
By reconstructing the distribution of matter over 6 billion years of the universe's history, these measurements allow us to know how much dark matter and dark energy there is at any given time.
“The final DES gravitational lensing measurement includes about 150 million galaxies, a dataset of extraordinary size.This is very stimulating, but also comes with a great responsibility: to ensure that every step of the analysis is completely reliable," says Simon Samourov, IFAE PhD student who led the cosmological analysis of galaxy distortions.
In this analysis, DES compared its data to two cosmological models: the standard model ΛCDM, with a constant dark energy density, and an extended model, wCDM, in which this density evolves over time.
DES found that their data largely matched the Standard Model of the Universe.The data also fit the developed dark energy model, but not better than the standard model.
However, one element common to both models presents a striking difference.In the previous analysis, the parameter that describes how objects in the universe cluster showed a different value of the grouping observed in the early universe than predicted by both models.In this new analysis, that difference widens when the current data is included.The difference remains even when DES combines its data with other experiments.
See alternative models
DES will then combine this work with new measurements from other dark energy experiments to study alternative models of gravity and dark energy.This analysis is also important because it paves the way for the new Vera C. Rubin Observatory, funded by the U.S. National Science Foundation and the U.S. Department of Energy Science Office, to conduct similar studies through the Space and Time Heritage Survey (LSST).
Anna Boreton, co-chair of the DES Large-Scale Structures Group and senior scientist at CIEMAT in Madrid, said: "The measurements will be very clear in a few years."Next year".
Dark Energy Exploration (DES) is an international collaboration of more than 400 scientists from 25 organizations in seven countries, led by the Fermi National Accelerator (Fermilab) lab, the US National Laboratory dedicated to particle physics and accelerator research.Fermi Forward Discovery Group operates Fermilab for the US Energy Department Science Office.
Spain became the first international partner to join the United States in establishing the DES project in 2015. Spain's participation is expressed through three institutions: in addition to researchers from the Institute of Theoretical Physics, two institutions in Barcelona - the Institute of Space Sciences (ICE-CSIC) and the Institute of Physics of Other Energies (IFAE) - and one in Madrid - the Center for Energy, Environment andof Technological Research (CIEMAT) – (IFT/CSIC-UAM).
