Star Births Plummet 50%
New stars form at less than half the rate of 4.5 billion years ago, despite ample hydrogen fuel.
Star formation across the universe has fallen dramatically over the past 4.5 billion years, despite the supply of neutral hydrogen, a key ingredient for making stars, barely declining. The rate of new star formation has fallen to less than half its previous level over the same period.
The research, led by scientists from the Chinese Academy of Sciences (CAS), used China's Five hundred meter Aperture Spherical radio Telescope (FAST) and data from roughly 2.5 million galaxies observed by the Dark Energy Spectroscopic Instrument (DESI) project. The findings, published online in Nature Astronomy on September 1, reveal a striking mismatch between the decline in star formation and the modest decrease in neutral atomic hydrogen.
Star formation was about 2.5 times higher 4.5 billion years ago, while neutral hydrogen levels were only about 1.4 times higher. This suggests that the decline in star formation is not solely due to a lack of fuel, but rather a more complex interplay of factors.
## Why it matters The decline in star formation has significant implications for our understanding of galaxy formation and evolution. As the universe ages, the rate at which new stars form is a key indicator of its overall health and activity. The findings of this research team highlight the need for further study into the underlying causes of this decline, and the role of neutral hydrogen in the star formation process.
The research team's use of cutting-edge technology, including the FAST radio telescope, has provided unprecedented insights into the evolution of the universe. As scientists continue to explore the mysteries of the cosmos, this study serves as a reminder of the complex and dynamic nature of the universe, and the need for ongoing research and discovery.
