Milky Way-like galaxy spotted in early universe raises fresh questions on cosmic evolution

Indian astronomers have identified one of the earliest known spiral galaxies in the universe — a massive, well-structured cosmic system that existed when the universe was barely 1.5 billion years old.

The discovery challenges current models of galaxy formation, which suggest early galaxies should be chaotic, clumpy and unstable rather than orderly and mature.

The galaxy, named Alaknanda, features two clean spiral arms wrapping around a luminous central bulge, mirroring the architecture of the Milky Way. At roughly 30,000 light-years across, it displays a level of refinement scientists believed would take billions of years to emerge.

“We have named it Alaknanda, after the Himalayan river,” said Professor Yogesh Wadadekar of the National Centre for Radio Astrophysics (NCRA-TIFR) in Pune, announcing the breakthrough on December 2.

Lead researcher and PhD scholar Rashi Jain, who first identified the galaxy, said the clarity of its structure took the team by surprise. “The galaxy looks remarkably similar to our own Milky Way despite being present when the universe was only 10 per cent of its current age,” she said.

Their findings have been published in the peer-reviewed European journal Astronomy and Astrophysics.

Alaknanda was detected using data from NASA’s James Webb Space Telescope (JWST) — the most advanced observational instrument ever deployed in space. Since its launch in 2021, JWST has steadily upended earlier assumptions about the early cosmos, revealing that many ancient galaxies appear more evolved than theoretical models predicted.

Jain said the name carries symbolic significance. “Just as the Alaknanda river is a sister to Mandakini — which is also the Hindi name for the Milky Way — this galaxy felt like a distant cosmic sibling.”

The team is now preparing for the next phase of investigation: mapping the internal motion of gas and stars to understand how such a well-formed spiral could exist so early in cosmic history.

“Whether the motion is chaotic or orderly will help us uncover how the spiral arms were built,” Wadadekar explained. Upcoming observations will combine JWST data with measurements from the ALMA observatory in Chile.

The discovery could reshape how astronomers understand galaxy evolution. If more such galaxies are found, scientists may need to rethink whether the early universe followed multiple evolutionary pathways rather than one predictable timeline.

“Alaknanda tells us that the universe was building complex structures far earlier than we imagined,” Jain said. “It’s a reminder that the cosmos still has surprises — and many of them may be waiting just beyond what we’ve been able to see.”