Produced by: Manoj Kumar
Data from the James Webb Space Telescope (JWST) has revealed that tiny dwarf galaxies lit up the early Universe, bringing light to the once dark, hydrogen-filled cosmos, according to Nature.
Astrophysicist Iryna Chemerynska of the Institut d’Astrophysique de Paris explains that these ultra-faint galaxies produced ionizing photons that transformed hydrogen, driving the early Universe’s reionization.
The Universe initially filled with a dense plasma fog after the Big Bang, making it dark and murky. As the Universe cooled, protons and electrons combined to form neutral hydrogen gas, setting the stage for cosmic dawn.
After 300,000 years, the first stars formed, emitting powerful radiation that reionized the gas and allowed light to travel freely. By the end of cosmic dawn, the Universe was fully illuminated.
Scientists initially believed massive black holes and large galaxies cleared the cosmic fog. However, JWST observations reveal that dwarf galaxies were the true catalysts for reionization.
Using JWST and Hubble data, researchers studied the galaxy cluster Abell 2744. The dense cluster magnified light from distant dwarf galaxies, allowing scientists to analyze them more closely.
Dwarf galaxies, despite their size, were surprisingly bright and abundant. These small galaxies outshined larger ones by producing four times the ionizing radiation per unit, according to astrophysicist Hakim Atek.
Credit : NASA
Dwarf galaxies outnumbered large galaxies by 100 to 1 during the early Universe, emitting enough collective energy to drive reionization and transform the state of the cosmos.
Astrophysicist Themiya Nanayakkara notes, “We’ve entered uncharted territory with the JWST.” The findings mark a major breakthrough, yet many questions remain as researchers aim to explore more cosmic regions.