A cosmic 'leaf blower': Light-propelled winds help explain early universe's bright galaxies
When astronomers looked at photos of the early universe taken by the James Webb Space Telescope, they found something odd: an overabundance of bright galaxies. Based on what they knew about the early universe, such galaxies should have been far less common in the few hundred million years following the Big Bang.
When astronomers studied early universe photos from the James Webb Space Telescope, they noticed an unexpected abundance of bright galaxies. Given their understanding of the early cosmos, such galaxies should have been scarce in the first few hundred million years after the Big Bang. To explain this phenomenon, researchers at the Simons Foundation's Flatiron Institute in New York City and the University of Texas at Dallas turned to advanced simulations.
They discovered that powerful ultraviolet radiation, known as Lyman-alpha radiation, produced by clusters of young stars, acts like a cosmic leaf blower. This radiation pushes away light-absorbing gas and dust, making the galaxies appear brighter. While Lyman-alpha radiation can repel low-density gas and dust effectively, its impact on star formation is limited in dense regions where gravity is strong.
However, in less dense areas, the radiation generates explosive winds that can eject material from galaxies, contributing to their increased brightness. The study, published in The Astrophysical Journal on November 4, 2026, suggests that understanding the role of Lyman-alpha radiation pressure in the early universe could provide crucial insights into galaxy formation and evolution.
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