The Oldest Stars Reveal the Age of the Universe ✦
Scientists estimated the age of the universe based on the age of the oldest stars in our Galaxy, using data on chemical composition and distances — much like determining the age of a forest from its oldest trees. It turned out that the oldest star has lived about 13.7 billion years, which almost matches cosmological calculations (13.8 billion). But could stars be older than the universe itself?
Tree rings tell the age of a forest. In a similar way, the oldest stars serve as cosmic chronometers. Studying the light of 155,600 stars in the vicinity of the Sun, astronomers found a record-breaker: a star 13.73 billion years old—it has just begun to swell, preparing to become a red giant. That's three times older than Earth.
After the Big Bang, it took stars 0.2 billion years to ignite. The sum—13.93 billion years—matches the predictions of the standard cosmological model, which includes dark matter (invisible scaffolding) and dark energy (the acceleration of expansion). But the Hubble tension (the discrepancy in expansion rate measurements) hints at a younger Universe—12.9 billion years. Such a young Universe is hard to reconcile with the existence of ancient stars right here in our Galaxy. Probably, the solution lies not in the past, but in observation methods.
Stars are living witnesses, whose chemical pattern preserves traces of supernova explosions and the effects of time dilation. The foundations were laid by Georges Lemaître, Edwin Hubble and Vera Rubin—their ideas are confirmed literally in our cosmic backyard.
🎯 The most ancient star turned out to be the same age as the galaxy, but is only now beginning to swell into a red giant. We caught it on the threshold of a grand transformation, though it's three times older than Earth itself.
🎬 In Poul Anderson's novel 'Tau Zero', time almost freezes for the crew of a ramped-up ship, while billions of years rush by outside. Studying ancient stars is a far more accessible, yet no less poignant way to touch the abyss of time without leaving our home Galaxy.