What is the significance of lower metallicity findings in galaxies observed shortly after the Big Bang?
It suggests fewer generations of stars had lived and died to create heavy elements
Metallicity refers to the abundance of elements heavier than hydrogen and helium—often called 'metals' by astronomers. These heavier elements are forged inside stars through fusion and then dispersed into the interstellar medium when those stars die, often in supernova explosions. A galaxy observed just a billion years after the Big Bang is expected to have significantly lower metallicity because it has not yet undergone the extensive cycles of star birth, element creation, and death that enrich later-generation galaxies like the Milky Way. Low metallicity directly constrains the types of stars active in that early environment and confirms that the enrichment processes require substantial cosmic time to accumulate heavy elements.
