'Milky Way has a twin': JWST finds fully formed galaxy 1 billion years after Big Bang
Produced by: Mohsin Shaikh
Cosmic twin
Zhúlóng, a spiral galaxy spotted by JWST, mirrors the Milky Way—despite forming just 1 billion years after the Big Bang.
Ancient spiral
Complete with sweeping arms and a dense star bulge, Zhúlóng’s structure defies what we expect from galaxies in the early universe.
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Size shock
At 60,000 light-years across and weighing 100 billion solar masses, Zhúlóng rivals modern galaxies in scale and complexity.
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Fast forward
Galaxies were thought to evolve slowly, but Zhúlóng’s rapid development throws cosmic timelines into question.
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Model mismatch
The discovery challenges the dominant Lambda-CDM model, which assumes galaxies form over billions of years via mergers.
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Theory tension
Researchers now wonder if existing models are incomplete—or if early galaxies grew via unknown mechanisms like rapid gas cooling.
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Element clue
Future tests will measure Zhúlóng’s metallicity, revealing how many star generations have lived and died within its disk.
Black hole?
Astronomers will also look for a central black hole, which could explain the galaxy’s unexpected structural maturity.
Rethink time
Zhúlóng isn’t just a discovery—it’s a cosmic curveball forcing scientists to rewrite how galaxies grow in the early universe.