Stars that should have vanished billions of years ago, still burning
In the ancient architecture of the cosmos, the James Webb Space Telescope has illuminated something that defies the expected order of stellar time: supermassive stars, each ten thousand times the mass of our Sun, still burning within globular clusters billions of years after they should have gone dark. Discovered by researchers including astrophysicist Corinne Charbonnel of the University of Geneva, these apparent 'fossil' stars suggest that the universe's earliest moments were far stranger and more creative than our models have allowed. Their improbable survival — made possible, it seems, through the merging of smaller stars — invites us to reconsider not only how stars are born and die, but how the universe itself first learned to build.
- Stars that should have burned out two million years into their lives appear to still exist inside clusters that are over ten billion years old — a contradiction that has shaken foundational assumptions in astrophysics.
- Between 100,000 and 1 million of these ancient giants have been detected, each roughly 10,000 times the mass of the Sun, hiding in plain sight within globular clusters until Webb's instruments made the invisible visible.
- The leading explanation — that smaller stars collided and merged, gifting the resulting object extra fuel and extra time — reframes stellar death as something that can, under the right conditions, be negotiated.
- Researchers at the University of Geneva and the University of Barcelona are now pressing toward confirmation, knowing that verifying this collision-merger scenario would fundamentally rewrite the story of globular cluster formation and early cosmic structure.
O Telescópio Espacial James Webb detectou algo que, segundo os modelos existentes, não deveria mais existir: estrelas supermassivas com até 10.000 vezes a massa do Sol, ainda ativas dentro de aglomerados globulares com mais de dez bilhões de anos. A astrofísica Corinne Charbonnel, da Universidade de Genebra, descreveu essas estrelas como extraordinárias, e os dados que sustentam sua existência foram publicados na revista Astronomy & Astrophysics. Para ela e sua equipe, esses objetos podem guardar pistas sobre como o universo se organizou em seus primeiros momentos.
O problema central é de tempo. Estrelas tão massivas deveriam esgotar seu combustível em apenas dois milhões de anos — uma fração ínfima da idade dos aglomerados onde foram encontradas. O pesquisador Mark Gieles, da Universidade de Barcelona, apontou a contradição: se essas estrelas existiram nesses aglomerados tão antigos, deveriam ter desaparecido há muito tempo, deixando apenas rastros indiretos.
A resposta pode estar em colisões. Dentro desses aglomerados densos, estrelas menores podem colidir com objetos mais massivos, fundindo-se e transferindo massa e energia. O resultado é uma estrela que ganha combustível extra e, com ele, tempo extra de vida — uma espécie de sobrevivência por absorção. Seus núcleos queimam em temperaturas extremas, alimentados por fusão intensa de hidrogênio.
Agora, o que resta é a confirmação. Se observações futuras validarem esse cenário de fusões e colisões, as implicações se expandem para além da astrofísica estelar, tocando a própria compreensão de como o universo tomou forma nos instantes iniciais após o seu começo.
The James Webb Space Telescope has detected something that shouldn't exist—or at least, shouldn't exist in the way astronomers thought it did. Somewhere in the ancient cosmos, between 100,000 and 1 million stars are burning that are each roughly 10,000 times the mass of our Sun. They live in what researchers call globular clusters, and they appear to be fossils from the universe's infancy, formed all at roughly the same moment billions of years ago.
These are not ordinary stars. Astrophysicist Corinne Charbonnel of the University of Geneva describes them as extraordinary, and the data supporting their existence comes from observations that would have been impossible just a few years ago. "Today, thanks to data collected by the James Webb Space Telescope, we believe we have found the first evidence of the presence of these extraordinary stars," Charbonnel said in research published in Astronomy & Astrophysics. The discovery matters because these objects may hold clues about how the universe assembled itself in its earliest moments.
What makes this discovery puzzling is a fundamental problem of time. Globular clusters themselves are ancient—between 10 and 13 billion years old. But supermassive stars of this magnitude should burn out quickly, exhausting their fuel in just two million years or so. Mark Gieles, a researcher now at the University of Barcelona, laid out the contradiction plainly: if these stars existed in clusters that old, they should have vanished long ago, leaving only indirect traces behind. Yet here they appear to be, detected by one of humanity's most powerful observatories.
The explanation lies in collision and merger. Smaller stars within these dense clusters can collide with more massive ones, combining their mass and energy in the process. When this happens, the merged star gains extra fuel and extra time—a reprieve from the normal death sentence that awaits such massive objects. In essence, these ancient stars found a way to cheat mortality, at least temporarily, by absorbing the material and energy of their neighbors. The cores of these merged objects burn hotter than ordinary stars, likely due to the intense hydrogen fusion happening at extreme temperatures.
What matters now is confirmation. If future observations can verify that this scenario is real—that these supermassive stars truly formed through collisions in globular clusters—the implications ripple outward. Understanding how these objects came to be would reshape what we know about globular cluster formation itself, and more broadly, about how supermassive stars develop anywhere in the universe. Gieles noted that confirmation "would provide an important step forward for our understanding of globular clusters and for the formation of supermassive stars in general, with numerous important implications." The ancient light reaching us now may be the key to understanding not just how stars form, but how the universe itself took shape in those first, crucial moments after the beginning.
Citas Notables
Thanks to data collected by the James Webb Space Telescope, we believe we have found the first evidence of the presence of these extraordinary stars.— Corinne Charbonnel, astrophysicist, University of Geneva
If the scenario of supermassive stars can be confirmed by future studies, this would provide an important step forward for our understanding of globular clusters and the formation of supermassive stars in general, with numerous important implications.— Mark Gieles, researcher, University of Barcelona
La Conversación del Hearth Otra perspectiva de la historia
Why does it matter that these stars are so much larger than our Sun?
Because size determines everything about a star's life. A star ten thousand times the Sun's mass burns through its fuel in a blink—two million years. Finding them in clusters that are billions of years old shouldn't be possible. It's like finding a mayfly that's lived for a century.
So how are they still there?
They're not, not really. What we're seeing is evidence they collided with other stars and merged. When smaller stars crash together, they pool their mass and energy. The resulting object gets more fuel to burn and more time to exist.
That sounds almost like they're feeding on each other.
In a way, yes. In the dense cores of these clusters, stars are close enough that collisions happen. The smaller ones don't survive as individuals, but their material doesn't go to waste—it extends the life of the merged star.
Why does this help us understand the early universe?
These clusters are among the oldest structures we can observe. If we can understand how these massive stars formed within them, we're reading a record written in the first moments of cosmic history. They're witnesses to how the universe assembled itself.
What happens if the theory is wrong?
Then we have to rethink how globular clusters work entirely. But the James Webb data is strong. The real work now is getting other telescopes to confirm what we're seeing.