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The James Webb Space Telescope picked up radiation from ionized helium — a telltale sign that the early Universe was lit by stars composed only of hydrogen and helium, the very first suns.
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400 million years after the Big Bang, the James Webb Space Telescope noticed a bright spot near the galaxy GN-z11 — like a distant lighthouse whose light pushed through the primordial darkness. Splitting the glow into colors, astronomers found a clear line of extremely hot helium, its atoms stripped of electrons by unimaginable heat.
Such a glow is produced only by stars almost entirely made of hydrogen and helium, with no heavy elements — the so-called first generation of stars (Population III). They lived short lives but shone with furious brightness, then exploded, scattering the first specks of carbon and oxygen.
A twist: the spot turned out to be not a single star, but an entire cluster — a collective beacon whose combined brilliance we see. Without these first suns, the cosmos would have remained a sterile sea of hydrogen and helium forever.
The first generation stars were likely hundreds of times more massive than the Sun and burned out in just a couple of million years — on cosmic timescales, less than a blink of an eye.