Astronomers find galaxy similar to Milky Way more than 12 billion light-years away

This ancient galaxy, SPT0418-47, has a surprising level of order and stability, defying theories about early cosmic chaos.

5 Key Takeaways

1. A galaxy similar to the Milky Way, named SPT0418-47, has been discovered over 12 billion light-years away, revealing surprising structure during the early universe.
2. The discovery was made using ALMA (Atacama Large Millimeter/submillimeter Array) in Chile, showing the galaxy as it appeared when the universe was only 1.4 billion years old.
3. SPT0418-47 has two significant features: a rotating disk and a central star bulge, challenging previous models of galaxy formation.
4. Gravitational lensing and computer modeling played key roles in reconstructing the true appearance of SPT0418-47.
5. The unexpected order and structure found in the galaxy indicate that well-ordered disks may have been present earlier in the universe than previously thought.

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Astronomers have made a groundbreaking discovery with the help of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. They have located a galaxy named SPT0418-47 more than 12 billion light-years away, capturing its appearance when the universe was just 1.4 billion years old. The light from this galaxy has traveled for over 12 billion years, giving researchers a unique glimpse into the distant past, when the universe was a mere 10% of its current age.

The discovery, published in the journal Nature, showcases a remarkable similarity between SPT0418-47 and our own Milky Way galaxy. The young universe was previously thought to be a chaotic realm where galaxies were still forming and developing unstable structures. However, this galaxy’s features challenge those long-held assumptions.

Surprising Structure in the Early Universe

SPT0418-47 exhibits two notable characteristics typically associated with more mature galaxies: a rotating disk structure and a dense central star bulge. These are hallmarks of the Milky Way, suggesting that structured, ordered galaxies existed much earlier than previously believed. Study author Francesca Rizzo from the Max Planck Institute for Astrophysics in Germany expressed that this discovery marks a significant advancement in understanding galaxy formation. “This result represents a breakthrough…showing that the structures we observe in nearby spiral galaxies and in our Milky Way were already in place 12 billion years ago,” Rizzo said.

Filippo Fraternali, a professor of gas dynamics and coauthor from the University of Groningen, added, “The big surprise was to find that this galaxy is actually quite similar to nearby galaxies, contrary to all expectations from the models and previous, less detailed, observations.”

Techniques and Future Implications

To observe such a distant galaxy, astronomers utilized a method called gravitational lensing. This natural phenomenon uses the gravitational pull of a nearby galaxy to bend and magnify the light from SPT0418-47, creating an image that appears as a ring of light surrounding another galaxy. With the help of computer modeling, scientists reconstructed the actual shape of SPT0418-47, which revealed its surprising level of order.

Simona Vegetti, another coauthor and leader at the Max Planck Institute, highlighted the anomaly, noting that despite the galaxy’s high star formation rate, it displayed the most ordered disk structure ever seen in the early universe. This observation hints at possible new theories about how early galaxies evolved over time.

Although SPT0418-47 likely developed into an elliptical galaxy, different from the Milky Way’s spiral form, this finding opens new avenues for understanding the early cosmos. Future studies using more advanced telescopes may determine whether similarly well-ordered galaxies were common soon after the Big Bang or whether SPT0418-47 was an exception.