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How would the Milky Way have looked in the early universe?
An international team of astronomers has spotted a candidate for the most distant spiral galaxy known. And, they said on April 16, 2025, it might be a peek at what our own Milky Way galaxy looked like in its youth. The Webb space telescope captured this galaxy as it existed just 1 billion years after the Big Bang. Originally, astronomers thought spiral galaxies grew over billions of years from chaotic, irregular masses. But with more and more evidence mounting, it appears spiral galaxies obtained their structure much earlier than once thought.
The scientists published their peer-reviewed research in the journal Astronomy & Astrophysics on April 16, 2025.
The Torch Dragon galaxy
The astronomers bestowed a pretty cool name on this galaxy, calling it Zhúlóng, or Torch Dragon. As lead author Mengyuan Xiao of the University of Geneva explained:
We named this galaxy Zhúlóng, meaning ‘Torch Dragon’ in Chinese mythology. In the myth, Zhúlóng is a powerful red solar dragon that creates day and night by opening and closing its eyes, symbolizing light and cosmic time.
Similarities to the Milky Way
The universe is nearly 14 billion years old. And we see Torch Dragon as it was 1 billion years after the Big Bang, or close to 13 billion years ago. Its light has traveled so far for so long across the universe to reach us that it has redshifted – or moved toward the red end of the spectrum – to a high degree. In fact, it has a redshift of 5.2, which makes it the highest redshift for any candidate spiral galaxy yet.
Despite what must be the galaxy’s young age, the researchers said it already shows:
a surprisingly mature structure: a central old bulge, a large star-forming disk, and spiral arms … features typically seen in nearby galaxies.
Xiao said:
What makes Zhúlóng [Torch Dragon] stand out is just how much it resembles the Milky Way in shape, size and stellar mass.
The Milky Way spans about 100,000 light-years across, comparable to Torch Dragon’s 60,000 light-years. And the newly discovered galaxy has more than 100 billion solar masses in stars. The scientists called it one of the most compelling analogues for our galaxy ever found so early in the universe.
Co-author Christina Williams of NSF NOIRLab said:
It is really exciting that this galaxy resembles a grand-design spiral galaxy like our Milky Way. It is generally thought that it takes billions of years for this structure to form in galaxies, but Zhúlóng shows that this could also happen in only one billion years.
What’s next?
The researchers found this galaxy in a wide-area survey, which Williams said:
… is essential for discovering massive galaxies, as they are incredibly rare.
The scientists hope that future observations with Webb and the and Atacama Large Millimeter Array (ALMA) will help them learn more about the galaxy. They’d like to confirm their observations and gain more information so they can understand how it formed. And, of course, they’d also like to find more giant spiral galaxies in the early universe.
Bottom line: Astronomers have discovered a grand-design spiral galaxy, similar to our own Milky Way galaxy, that existed 1 billion years after the Big Bang.
Source: PANORAMIC: Discovery of an ultra-massive grand-design spiral galaxy at z ~ 5.2
Via Université de Genève
Via NOIRLab