The universe is entering its twilight era, according to new research conducted by an international team of 175 astronomers using data from the European Space Agency’s Euclid and Herschel telescopes. The findings confirm that the rate of star formation has peaked, and from now on, the cosmos will become progressively colder, darker, and less active.
By analyzing a massive catalog of observations from both telescopes, scientists have produced the most comprehensive temperature measurements of the universe to date. They examined the heat emitted by stellar dust in over two million galaxies, revealing that during the past 10 billion years, galaxies have cooled slightly and star formation has steadily declined.
According to Douglas Scott, cosmologist at the University of British Columbia and co-author of the study, this trend signals that “the peak of cosmic evolution is behind us.” The team estimates that while the universe may still exist for tens of billions—or even quintillions—of years, its energetic phase is effectively over. “From this point on, the universe will become colder and more lifeless,” Scott said. “The amount and temperature of dust in galaxies have been dropping for billions of years, meaning we’ve passed the era of maximum star formation.”
The Euclid telescope, launched by ESA in 2023, released its first major dataset in March 2025, including observations of 26 million galaxies stretching over 10.5 billion light-years. Its ultimate goal is to map 1.5 billion galaxies, covering nearly one-third of the visible night sky. To achieve this breakthrough, researchers combined Euclid’s data with archival measurements from Herschel, ESA’s far-infrared observatory that operated from 2009 to 2013. While Euclid captures visible and near-infrared light, Herschel focused on far-infrared wavelengths, enabling a deeper understanding of the thermal properties of galactic dust.
This combination allowed scientists to obtain the most precise temperature readings of galaxies ever recorded. Their analysis revealed that the average galactic temperature has fallen by about 10 Kelvin over the last ten billion years. Early galaxies observed in the study had average dust temperatures of 35 K (−238°C). Though modest, these changes are crucial, as dust temperature strongly correlates with star formation rates — hotter galaxies tend to form more stars because they contain greater amounts of massive, energetic stellar material.
As galaxies age, they gradually exhaust their star-forming fuel. Some lose gas during mergers, while others have their material expelled by supermassive black hole outbursts. Once deprived of sufficient gas and dust, galaxies fade into dormancy — their stars burn out, and their ability to create new ones disappears.
Conclusion:
This new research offers one of the clearest confirmations yet that the universe is slowly dying. Although the process will unfold over an unimaginably long timescale, the decline in star formation marks the end of an era. The cosmos, once teeming with fiery activity and the birth of countless stars, is now entering a quiet, fading phase — a testament to the inevitable cooling and darkening of everything that exists.
