Earlier this year, the European Space Agency’s Euclid telescope began sending home tons of data from billions of light-years away. Astronomers digging through the numbers found evidence that the universe is cooling off, and the golden age of star-making is over.The universe is old, in other words. Over the hill. Past its prime. It’s no longer of baby-making age.A team of 175 astronomers used Euclid’s fresh data and archival infrared readings from the retired Herschel telescope to build the most detailed heat map of the universe to date. Their conclusion, published as a preprint on arXiv, reads like a galactic obituary: star formation peaked billions of years ago. Galaxies are now running low on cosmic fuel. “The Universe will just get colder and deader from now on,” said Douglas Scott, a cosmologist at the University of British Columbia.The Universe Is Middle-Aged, Tired, and Probably Needs a Nap, Scientists SayAs reported by Live Science, the team analyzed emissions from 2.6 million galaxies stretching across 10 billion light-years. They tracked how stardust radiated heat across time, adjusting for redshift as galaxies drifted farther away. They found a slow, measurable cooling trend.Ten billion years ago, the average dust temperature sat around 35 Kelvin (-396°F). Now it’s about 25 Kelvin. That’s a tiny but still significant cooldown that signals that galaxies are losing their spark.Hotter galaxies are where stars are born; cooler ones are more like retirement homes. The data suggest we’re solidly in the shuffleboard-and-bingo phase. The universe, once an energetic, energizing upstart that spawned countless blazing-hot young suns, is now coasting toward a quieter, colder future.We down here won’t notice a thing. This slow fade will unfold over tens of billions of years. We have other things to worry about, like how our planet is getting hotter faster. The universe won’t be dying tomorrow, next year, or anytime soon, but its prime is over.The post The Universe Is Officially Past Its Prime, According to Astronomers appeared first on VICE.