The space telescope James Webb has for the first time caught light from stars of pure hydrogen and helium — just what the very first stars after the Big Bang are believed to have been made of. A giant cluster of galaxies MACS J0416 helped to see them: its gravity acted as a cosmic magnifying glass, amplifying the faint glimmer of the distant galaxy LAP1-B.

The newborn stars inside it fit theoretical predictions perfectly. They arise in tiny clumps of dark matter — the invisible framework of the cosmos. Each star is a true heavyweight, a hundred times more massive than the Sun, while the whole cluster weighs in at only a couple of thousand solar masses. Some of them have already exploded as supernovae, enriching the surrounding gas with heavier elements.

Here's the twist: the very, very first stars ignited even earlier, but their light is so faint that even Webb couldn't spot them. LAP1-B isn't the absolute beginning, but a rare chance to see an almost pristine past. According to calculations, only one such object appears in the entire sky.