The James Webb Space Telescope (JWST) may have made a groundbreaking discovery: the first generation of stars born shortly after the Big Bang. These primordial stars, known as Population III (POP III) stars, are theorized to have formed in the universe’s infancy, and evidence suggests they may have been observed within a distant galaxy called LAP1-B.
The Significance of Population III Stars
POP III stars are crucial to understanding the universe’s early evolution. They formed before the universe was enriched with heavier elements, meaning they were composed almost entirely of hydrogen and helium. These stars were likely massive, potentially hundreds of times the mass of our Sun, and their existence helps explain how the first galaxies emerged from the “cosmic dark ages” – the period before the universe was illuminated by starlight.
How the Discovery Was Made
The light from LAP1-B has traveled for 13 billion years to reach JWST, meaning we are observing the galaxy as it existed just 800 million years after the Big Bang. The extreme distance makes the galaxy faint, but a phenomenon called gravitational lensing enabled the observation. Predicted by Albert Einstein, gravitational lensing occurs when the gravity of a massive object (in this case, a galaxy cluster 4.3 billion light-years away) bends and magnifies the light from a more distant object. This “magnifying glass” effect made LAP1-B visible to JWST’s powerful infrared sensors.
Evidence Points to Primordial Stars
Researchers believe the stars within LAP1-B are POP III based on several key indicators:
- Low Metallicity: The gas surrounding the stars contains almost no heavy elements, consistent with the expected composition of primordial stars.
- Massive Clusters: The stars appear to be grouped in clusters of around 1,000 times the mass of our Sun, which aligns with theoretical models of how POP III stars formed.
- Epoch of Reionization: The galaxy is observed during the “epoch of reionization,” when the first stars and galaxies were transforming neutral gas into plasma, marking the end of the cosmic dark ages.
Why This Matters
Identifying POP III stars has been a major goal in cosmology. These stars provide clues about the earliest stages of galaxy formation, the properties of dark matter, and the universe’s initial conditions. The discovery suggests that gravitational lensing could be a powerful tool for finding more POP III stars at extreme distances.
“If indeed then stars of LAP1-B are Pop III, this is the first detection of these primordial stars,” said Eli Visbal, the team leader from the University of Toledo.
Next Steps
Researchers are planning more detailed simulations to confirm the findings and explore the transition from POP III to later generations of stars. This discovery opens a new window into the universe’s earliest history, promising further insights into the origins of galaxies and the evolution of the cosmos
