Significant primordial star formation at redshifts z ≈ 3–4

Four recent anomalous results obtained during observation of high-redshift galaxies can be resolved at a stroke if a simple modification is made to the current models of galaxy formation. The modification is the assumption that 10–30% of the stars in many galaxies at redshifts of z = 3 to z = 4 are ‘primordial’. That is, they have not been enriched by metals — which to cosmologists means anything heavier than helium. Previously it had been assumed that micromixing of the heavier elements would have been extensive at the giga-year timescales implicit at these relatively low redshifts.