The universe had to make stars before it could make almost everything familiar. Carbon, oxygen, silicon and iron were not present in meaningful quantities after the Big Bang. They had to be forged inside stars and returned to space before later generations of stars, rocky planets and living chemistry could exist.<\/p>\n
That logic requires a first generation, yet no individual member of it has been conclusively identified. Astronomers call these hypothetical pioneers Population III stars: objects born from essentially pristine hydrogen and helium, before previous stars had enriched their surroundings with heavier elements.<\/p>\n
The often quoted interval of 100 to 250 million years after the Big Bang is a useful model-based bracket, not an observed timestamp. NASA says the first stars may have formed as early as 100 million years after the Big Bang. A galaxy observed much later has provided evidence that substantial star formation was already under way by about 250 million years. Some current simulations permit the earliest examples even sooner.<\/p>\n
The title\u2019s second apparent contradiction is real only at first glance. A massive first star could die after a few million years while the photons it released kept travelling for more than 13 billion years. Webb would see the star during its brief life, not as it exists now.<\/p>\n
The date is inferred rather than observed<\/p>\n
About 380,000 years after the Big Bang, the universe cooled enough for electrons to join atomic nuclei. Space became transparent, leaving neutral hydrogen and helium gas, dark matter and small density variations. There were no stars yet. The period before the first sustained sources of light is known as the cosmic dark ages.<\/p>\n
Gravity slowly amplified those variations. Gas collected inside small dark-matter haloes, and molecular hydrogen allowed some of it to lose heat. Once a dense core could no longer support itself, it collapsed towards a protostar. The sequence is physically plausible, but its timing depends on assumptions about halo growth, chemistry, turbulence, radiation and how rapidly the gas fragments.<\/p>\n
A major 2023 review of first-star formation<\/a> by Ralf Klessen and Simon Glover describes a field in which increasingly detailed simulations have replaced the simplest one-halo, one-star picture. Discs can fragment into several protostars. Those objects can merge, eject one another or keep accreting. Feedback from one growing star changes what its neighbours can become.<\/p>\n This is why the formation window should not be treated like a historical date. The 100-million-year edge is close to NASA\u2019s \u201cas early as\u201d summary. The 250-million-year figure also appears in a 2018 Nature analysis of MACS1149-JD1<\/a>, whose oxygen and stellar population implied star formation at that cosmic age. That galaxy was not the first stellar nursery, and its inferred history did not reveal the universe\u2019s first individual star. It established how early an already evolving system had to begin building stars.<\/p>\n Population III describes chemistry, not age alone<\/p>\n The Big Bang produced overwhelmingly hydrogen and helium, plus traces of lithium. Astronomers refer to every element heavier than helium as a metal. A genuine Population III star therefore begins with effectively zero metals, rather than merely being very old.<\/p>\n The distinction matters because metals alter how a gas cloud cools. Carbon, oxygen and dust can radiate energy efficiently, helping enriched clouds break into many small dense pieces. Pristine gas has fewer cooling routes. Early calculations consequently favoured very massive first stars, often tens or hundreds of times the Sun\u2019s mass.<\/p>\n The modern picture is wider. Simulations still tend to produce a top-heavy mass distribution, meaning more massive stars relative to a modern stellar population, but fragmentation can also make lower-mass objects. A star\u2019s age, location or low iron content cannot by itself establish Population III status. The decisive condition is that it formed before any earlier stellar generation polluted its birth material.<\/p>\n A few million years is the massive-star answer<\/p>\n Massive stars spend fuel at extraordinary rates. NASA\u2019s detailed guide to the first stars<\/a> notes that a 60-solar-mass star would shine for less than one million years. A 100-solar-mass example could reach a surface temperature near 100,000 kelvins and radiate with roughly a million times the Sun\u2019s power.<\/p>\n Such objects do not fade gently. Depending on mass and internal evolution, they may explode and leave neutron stars or black holes, undergo pair-instability supernovae that destroy the whole star, or collapse directly into black holes. Their ultraviolet radiation also ionises surrounding hydrogen, while their explosions distribute the first heavy elements. One short life can change the chemistry and temperature of the next stellar nursery.<\/p>\n The phrase \u201cdied within a few million years\u201d therefore applies to the massive stars expected to dominate the first generation\u2019s light. It is not a claim about every possible metal-free star. Physics allows a Population III star below roughly 0.9 solar masses to survive until today. None has been found, which is one reason a first generation dominated by much higher masses remains plausible, but the absence is not proof that no low-mass examples formed.<\/p>\n A dead star\u2019s light can still be arriving<\/p>\n A star\u2019s lifetime and its light\u2019s travel time are separate clocks. Imagine a star shining for three million years and then collapsing. Photons released during those three million years continue moving outward after the source has gone dark. If some reach Webb today, the telescope records the star as it was more than 13 billion years ago.<\/p>\n This is not a delayed view of a surviving object. Astronomy supplies a lookback time. The more distant the source, the earlier the chapter being observed. And because the universe expanded while the light travelled, wavelengths that began mainly in the ultraviolet have been stretched into the visible and infrared bands that Webb can detect.<\/p>\n Distance nevertheless leaves very few photons for a telescope. An individual first star is much fainter than the combined stellar and nebular light of a young galaxy. Its apparent position may also blend with nearby sources. Webb\u2019s large mirror and infrared instruments make the measurement less impossible, but not routine.<\/p>\n The best current candidates remain systems<\/p>\n LAP1-B shows how close the search has come, and how careful the wording must be. In 2025, Eli Visbal, Ryan Hazlett and Greg Bryan argued in The Astrophysical Journal Letters<\/a> that the highly magnified object agreed with three theoretical expectations for Population III stars. It occupied a suitably small halo, could contain a top-heavy population and had the low total stellar mass expected for a tiny primordial system.<\/p>\n That made LAP1-B a serious candidate, not a confirmed isolated first star. A 2026 Nature study<\/a> measured its gas-phase oxygen abundance at about 0.0042 times the solar value, with substantial uncertainty. That is extraordinarily primitive, but not zero. The system may preserve material enriched by the first stars shortly after they died. It does not supply an unambiguous spectrum from one pristine star.<\/p>\n SpaceDaily\u2019s earlier account of the attempt to see first-born stars<\/a> described the same basic evidential problem. A missing metal line can indicate a pristine source, or it can mean the observation was not sensitive enough. A compact glow may come from one star, a cluster, ionised gas, an accreting black hole or some combination of them.<\/p>\n Earendel showed what a foreground cluster can do<\/p>\n Gravity offers a way around the shortage of photons. A massive foreground galaxy cluster bends space-time and redirects light from a more distant source. Under the right alignment, the cluster acts as a natural telescope, magnifying and sometimes multiplying the image behind it.<\/p>\n Earendel is the clearest proof that this can expose an individual star at extreme distance. It appears in the Sunrise Arc galaxy as seen when the universe was about one billion years old. NASA\u2019s Webb follow-up<\/a> says the star was magnified by at least 4,000 and identifies it as a massive B-type star roughly one million times as luminous as the Sun.<\/p>\n Earendel is not a confirmed Population III star. It lived too late, in a galaxy that had already experienced chemical evolution. Its importance here is methodological. Hubble and Webb isolated a stellar point that would have been far below their normal detection limits. Nature supplied most of the effective magnifying power.<\/p>\n The useful lensing events are exceptionally narrow<\/p>\n