For years, scientists have chased a dream: discover the first stars in the universethose who illuminated the darkness immediately after the big Bangmore than 13 billion years ago. Now, a group of astronomers led by Ari Visbalfrom the University of Toledo (Ohio), thinks he has finally found them.
The clue comes from a very distant galaxy, called LAP1-Bobserved by James Webb Space Telescope (JWST). Analyzing its light, scholars noticed something different than usual: traces of primordial starsthe mysterious ones Population III stars.
These stars were nothing like the ones we know today. They were only made up of hydrogen, helium and a pinch of lithiumthe only elements born from the Big Bang. No iron, no carbon, no “metal” that we also find in our bodies today. In practice, they were the cosmic mothers of all the stars that came after.
The first lights of the cosmos
The stars of Population III they were gigantic, until a thousand times more massive than the Sunand they lived very little: they burned quickly, exploding like supernovae and leaving behind the first traces of heavy elements. But until now no one had been able to find clear proof of this.
This is why the discovery of LAP1-B causes so much talk. The galaxy is located within a halo of dark matter about 50 million times more massive than the Sun – just as theoretical models predicted. And the gas that surrounds it contains very few metalsa sign that we are faced with a system so young that it still preserves the memory of the first stars.
In other words, we may be watching the dawn of the universethe moment when matter began to shine for the first time.
A new way to explore the universe’s past
The discovery, published on The Astrophysical Journal Lettersit is not yet a definitive confirmation. Astronomers want to make sure they don’t misinterpret the data: we need to understand, for example, how much matter the first supernovae really dispersed and whether current models are accurate.
But one thing is certain: the method works. Combining the power of JWST with the technique of gravitational lensing – an effect that amplifies the light of the most distant galaxies thanks to the gravity of the closest ones – opens up new possibilities for exploring the primordial cosmos.
As the researchers write, LAP1-B may be just the first of many more galaxies to be discovered. Perhaps out there, beyond the fog of time, the remnants of the universe’s first stars still shine.
