Groundbreaking JWST observations reveal the pivotal role of low-mass galaxies in the early universe’s reionization, challenging existing cosmic evolution theories.
Scientists working with data from NASA’s James Webb Space Telescope (JWST) have obtained the first full spectra of some of the earliest starlight in the universe. The images provide the clearest picture yet of very low-mass, newborn galaxies, created less than a billion years after the Big Bang, and suggest the tiny galaxies are central to the cosmic origin story.
The international team of researchers, including two Penn State astrophysicists, published their results recently in the journal Nature. The spectra reveal some of the first visible light from a period in the universe known as reionization, which was powered by the arrival of the earliest stars and galaxies.
The Primordial Universe: A Transition From Darkness to Light
Normal matter in the universe started as a hot, dense fog made almost entirely of hydrogen and helium nuclei, explained Joel Leja, assistant professor of astronomy and astrophysics at Penn State and author on the paper. As it expanded and cooled, lone protons and electrons started bonding, forming neutral hydrogen for the first time. Then, roughly 500 to 900 million years after the DOI: 10.1038/s41586-024-07043-6
Bingjie Wang, a postdoctoral scholar in astrophysics, is the other Penn State co-author on the study. A full list of authors and their respective institutions is available on the published paper. The researchers acknowledge funding and support from CNES, the Programme National Cosmology and Galaxies, CEA, the Cosmic Dawn Center, the Danish National Research Foundation, the Australian Research Council, the NOW, the European Commission’s and University of Groningen’s CO-FUND Rosalind Franklin program, the United States-Israel Binational Science Foundation, the U.S. National Science Foundation (NSF), the Ministry of Science & Technology, Israel and