Are you one of the authors of this paper? Email us from your institutional or work email address mentioning this article's arXiv ID and we'll verify you and give you edit access to this page.
Are you an author who sees something we missed or got wrong? Write to us — the subject line already carries the paper id. We read every note and correct the write-up.
Are you an author of this paper and would prefer our analysis not to be published? Email us from your institutional address; once confirmed, we will take the page down.
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.
📄 Showing the "Simple" version — "Advanced" is not ready yet. Add it to favorites to help prioritize it.
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.