Paris, France – Scientists have made a groundbreaking discovery that sheds light on the early Universe and its evolution. Through data gathered by the Hubble and James Webb Space Telescopes, researchers have uncovered the origins of the free-flying photons in the cosmic dawn – small dwarf galaxies. These galaxies played a crucial role in transforming neutral hydrogen into ionized plasma during cosmic reionization, a process that shaped the Universe’s history.
At the dawn of the Universe, space was filled with a dense fog of ionized plasma, making it dark and devoid of light. However, as the Universe cooled, protons and electrons combined to form neutral hydrogen and helium gas. The first stars born from this gas emitted radiation that reionized the gas, leading to the Universe becoming illuminated approximately 1 billion years after the Big Bang.
While scientists previously believed that powerful sources like black holes and large galaxies were responsible for reionization, recent observations from the James Webb Space Telescope suggest a different story. Through detailed analysis of dwarf galaxies, researchers found that these small galaxies outnumber large galaxies and collectively emit more ionizing radiation than previously assumed.
The research, spearheaded by astrophysicist Hakim Atek of the Institut d’Astrophysique de Paris, focused on the galaxy cluster Abell 2744. Using data from the James Webb Space Telescope and Hubble, the team identified tiny dwarf galaxies near the cosmic dawn and discovered that these galaxies are far brighter and more abundant than expected.
Despite their small size, these low-mass galaxies are powerful producers of energetic radiation, playing a significant role in transforming the state of the Universe. Further studies are planned to ensure the sample of dwarf galaxies examined is representative of the entire population in the cosmic dawn, but these initial findings are promising in unraveling the mysteries of reionization.
As researchers delve deeper into the early Universe with the James Webb Space Telescope, new questions arise about the evolutionary history of our beginnings. The work being done provides a glimpse into uncharted territory, offering exciting prospects for uncovering more secrets of the Universe’s formation.