Hubble Finds Stellar Winds Block, Not Clear, Early Cosmic Fog

Hubble observations show that winds from early supernovae may have trapped, rather than released, ionizing radiation, overturning a key assumption about the universe’s reionization. Astronomers used Hubble’s ultraviolet imaging to study galaxies about 13 billion years old, when the intergalactic medium was still opaque to light. The data reveal that the outflows from massive star explosions create dense shells that absorb high‑energy photons, preventing them from escaping into space. This contradicts the prevailing view that such winds cleared the cosmic fog, allowing the universe to become transparent. The result compels scientists to revisit models of the epoch of reionization and explore alternative sources, such as early quasars or exotic processes, that could have driven the transition. The study, published in ScienceDaily, underscores the need for new observations with next‑generation telescopes to map the early universe’s ionization state.