过去45亿年间宇宙原子氢的微弱演化

通过对超过250万个星系的光谱学观测，研究发现宇宙在过去45亿年间保留了大部分原子氢。尽管恒星形成率急剧下降，但这一结果表明气体转化效率低下，而非原子气体储备耗尽所致。

Nature Astronomy, Published online: 01 September 2026; doi:10.1038/s41550-026-02965-9 Spectroscopy from over 2.5 million galaxies shows that the Universe has retained most of its atomic hydrogen over the past 4.5 billion years even as star formation fell sharply, pointing to inefficient gas conversion rather than depletion of the atomic gas reservoir.