JWST finds early galaxies were already seeding the universe with heavy elements

When the universe was still in its infancy—only 500 million years after the Big Bang, or about 3% of its current age—some of the universe's earliest stars and galaxies had already formed. Astronomers have long predicted that much of the gas surrounding these young galaxies must have remained relatively pristine, composed mostly of hydrogen and helium, the primordial ingredients available in the newborn cosmos.