Pune: Two astronomers from Pune-based National Centre for Radio Astrophysics, using the powerful James Webb Space Telescope (JWST), have discovered what could be one of the earliest spiral galaxies ever detected, complete with clearly observable arms, just like our own Milky Way.It’s a surprising discovery, said astronomers Rashi Jain and Yogesh Wadadekar, who named the galaxy ‘Alaknanda’, after the Himalayan river in Uttarakhand. In their findings, they note Alaknanda — which is located 12 billion light years away and is 30,000 light years across — likely formed when the Universe was only about 1.5 billion years old, which means the galaxy took shape in record time. Their discovery then challenges known models of galaxy formation as scientists believe galaxies that formed this quickly after the Big Bang should be chaotic and irregular in design.“But Alaknanda has the textbook grand spiral design, two clear spiral arms wrapped around a bright centre,” said Jain. “It looks surprisingly similar to the Milky Way even though it came into existence when the Universe was only 10% of its present age,” she added.Wadadekar, the study’s co-author, said: “It looks like a regular, well-structured system. Such galaxies should take at least three billion years to develop stable spiral arms. Here, we are seeing a galaxy that seems to have completed this entire construction process in half that time.”The Milky Way, in comparison, took billions of years to form its spiral discs.Jain and Wadadekar’s discovery was recently published in the journal Astronomy and Astrophysics.During Tuesday’s press conference at NCRA, held to announce their findings, the two scientists said they will continue to study Alaknanda as it has shown another “remarkable” property — it’s forming new stars at an extremely rapid rate, nearly 30 times higher than the Milky Way today. In fact, observations suggest the galaxy contains around 10 billion times the mass of the Sun in stars. “Its spiral arms show a beads-on-a-string pattern that signals active star formation,” Jain said.Originally from Bharatpur in Rajasthan, Jain is a PhD researcher who has been studying galaxies using the James Webb Space Telescope. For one-and-half-years now, she’s been working with Wadadekar as his doctoral student. Wadadekar himself is an astronomer who has studied the evolution of galaxies using ground- and space-based telescopes. Their research on Alaknanda was published on Nov 10.He said the team’s next goal would be to study the motion of stars and gas within the newly discovered galaxy. “If we can measure their velocities using JWST’s spectroscopic instruments, we will be able to understand how this galaxy assembled so fast,” he said. “We have one remarkable example today. Now we need to find more such galaxies to understand the bigger picture.”Alaknanda’s discovery has already provided a vital clue to suggest the early Universe was a far more complex space than previously thought. Scientists earlier believed the early Universe was filled with chaotic and clumpy galaxies and that stable spiral structures would only appear much later.“That idea was based on theories that young galaxies were too turbulent and hot to settle into rotating discs. But JWST has repeatedly revealed well-formed discs. And Alaknanda is the clearest such example so far that suggests the Universe matured faster than expected,” Wadadekar said.He added: “The low contribution of light from its central bulge suggests Alaknanda grew mainly through smooth gas accretion rather than through major collisions. But such a process is expected to take about a billion years to create spiral arms, longer than the 600-million-year timespan in which the galaxy formed most of its stars. This mismatch points to gaps in our understanding of spiral galaxy formation.”