International scientists explain why universe forms fewer stars

The latest observations indicate that whilst neutral hydrogen is abundant, the process by which gas is converted into stars has slowed down, altering our understanding of galaxy evolution

An international team of astronomers led by the Chinese Academy of Sciences analysed data collected by the "Chinese Sky Eye" (FAST) and the Dark Energy Spectroscopic Instrument (DESI), covering approximately 2.5 million galaxies across about one-third of the sky. Using spectral line stacking – a technique that combines faint 21-centimetre radio signals from approximately 2.5 million galaxies – the scientists have, for the first time, traced the evolution of neutral atomic hydrogen (the primary fuel for stars) on cosmic timescales with sufficient statistical precision.