James Webb finds early galaxies spewing oxygen, carbon and silicon within 500 million years of the Big Bang
JWST observations reveal that galaxies as early as 500 million years after the Big Bang were already ejecting oxygen, carbon and silicon into surrounding space.
Using nearly 30 hours of JWST exposure, astronomers identified blueshifted absorption signatures of oxygen, carbon and silicon in the gas surrounding three galaxies observed at redshifts between 7.2 and 9.3. The blueshifts imply that metal-laden gas is flowing outward at speeds of about 50-250 km/s, consistent with winds powered by supernovae and massive stars. This demonstrates that heavy-element production and distribution began within the first 500 million years after the Big Bang, earlier than previously thought.
The result revises the picture of the early universe from a largely untouched hydrogen-helium mix to one already undergoing baryon cycling and chemical complexity. It also offers a possible explanation for the difficulty in detecting truly pristine Population III stars, as early enrichment may have quickly contaminated primordial gas. Further JWST studies are needed to gauge how widespread such outflows were and how they influenced later galaxy evolution.
Why it matters
It shows the universe became chemically complex far sooner, affecting models of early galaxy formation and the search for primordial stars.
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