国际研究团队近日发现，过去45亿年间宇宙的星形成率下降了50%以上，但中性氢的供应量仅下降约30%1。具体而言，45亿年前的星形成率约为现在的2.5倍，而同期中性氢密度仅为现在的1.4倍1。这表明星形成衰退的幅度远超气体供应的减少幅度，质疑了气体耗尽是导致星形成衰退主要原因的既有理论1。
该研究由中科院国家天文台、上海天文台和上海交通大学主导，利用中国FAST射电望远镜和DESI项目数据进行分析1。研究团队对约250万个星系进行了观测，样本覆盖天空约三分之一的区域1。研究成果已于2026年9月1日发表在《自然天文学》期刊上1。这项发现改变了天文学家对宇宙气体循环的理解1。
An international research team has discovered a puzzling mismatch between declining star formation and the availability of hydrogen fuel in the universe. Using data from China's FAST radio telescope and the DESI project, scientists found that over the past 4.5 billion years, the cosmic star formation rate has dropped by more than 50%, yet the supply of neutral hydrogen has declined by only approximately 30% 1.
The disparity challenges conventional explanations for the slowdown in stellar birth. Stars form from neutral hydrogen gas, so the dramatic difference in these decline rates suggests that gas depletion alone cannot account for the observed collapse in star formation 1. The research, led by institutions including the National Astronomical Observatories of the Chinese Academy of Sciences, Shanghai Astronomical Observatory, and Shanghai Jiao Tong University, analyzed approximately 2.5 million galaxies spanning roughly one-third of the sky 1. The findings, published in Nature Astronomy on September 1, 2026, indicate that the cosmic star formation rate was approximately 2.5 times higher 4.5 billion years ago, while neutral hydrogen density was only about 1.4 times higher during the same period 1. These results reshape current understanding of how gas cycles through the universe 1.
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