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A major international research effort has confirmed the standard model of cosmology using data from 41 million galaxies.
The Kilo-Degree Survey (KiDS), which has been mapping the distribution of matter in the universe for over a decade, released its final dataset, known as 'KiDS-Legacy', on 18 March 2025.
This conclusion comes as a surprise to researchers, as previous KiDS results had suggested possible inconsistencies in our understanding of dark matter and the large-scale structure of the universe.
Our key contribution
We played a significant role in this pioneering research, with Dr Maximilian von Wietersheim-Kramsta from our top-rated Physics department contributing to the main cosmological analysis of weak gravitational lensing data.
Weak gravitational lensing, a phenomenon where light from distant galaxies is subtly distorted by massive objects, was the primary method used in the KiDS project to estimate the distribution of dark matter.
Since its inception in 2011, the KiDS survey, carried out with the Very Large Telescope Survey Telescope in Chile, has mapped the shapes of over 40 million galaxies.
Our involvement helped refine the data analysis, ultimately leading to more precise conclusions about the structure of the universe.
Cosmological mystery
Earlier KiDS studies suggested that dark matter was distributed more smoothly than predicted by the standard cosmology model, challenging data from the Planck satellite.
However, the final KiDS-Legacy results, using improved calibration methods and more sophisticated analysis techniques, now align with the standard model.
The research team utilised enhanced redshift measurements and included more distant galaxies in their study—extending their observations to 10.4 billion light-years from Earth.
The study findings have important implications for future space missions like Euclid, which aims to study dark energy and the expansion of the universe.
Dr Maximilian said: "The Kilo-Degree Survey has said its last word on one of the most polarising tensions in cosmology! The final KiDS results reconcile early- and late-Universe measurements of the distribution of dark matter in the Universe.
"As we enter the golden era of gravitational lensing with surveys such as Euclid, this analysis drives the state-of-the-art of weak lensing cosmology and teaches us important lessons for the future."
Image: The Kilo-Degree Survey has taken images of 41 million galaxies in its eight years of observation. This image shows a section of the data set.
