A team of researchers has identified a large, spiral galaxy named Alaknanda, located approximately 12 billion light-years away. This discovery, made using NASA’s James Webb Space Telescope, reveals a galaxy that formed shortly after the Big Bang, when the universe was only about 1.5 billion years old. Observations indicate that Alaknanda displays a remarkably structured spiral shape, challenging previous assumptions about early galaxy formation.
For many years, astronomers believed that galaxies in the early universe were too chaotic to develop into orderly spiral formations. Previous observations from the Hubble Space Telescope supported this view, suggesting that such galaxies became scarce beyond approximately 11 billion years in look-back time. The emergence of Alaknanda raises critical questions about the dynamics of galaxy formation during this period.
Yogesh Wadadekar, a co-author of the study from the Tata Institute of Fundamental Research in India, remarked, “Alaknanda reveals that the early universe was capable of far more rapid galaxy assembly than we anticipated.” He noted that this galaxy has managed to gather a mass equivalent to 10 billion solar masses into a well-defined spiral disk in just a few hundred million years, which is remarkably swift in cosmic terms.
Galactic Features and Formation Insights
The James Webb Space Telescope’s advanced capabilities have allowed for the detection of both disk-shaped and spiral galaxies from the early universe. Alongside Alaknanda, other spiral galaxies such as CEERS-2112 and REBELS-25 were identified in 2023 and 2024, respectively. This growing body of evidence suggests that early galaxies may have formed structures much earlier than previously predicted.
Alaknanda spans around 32,000 light-years across and features a well-defined, rotating disk with two distinct spiral arms. These arms display smooth, symmetrical characteristics, categorizing Alaknanda as a “grand-design” spiral galaxy. The presence of bright chains of newborn stars along these arms indicates intense star formation, where gas has collapsed into denser regions, igniting new stellar bodies.
The researchers utilized a phenomenon known as gravitational lensing to observe Alaknanda in unprecedented detail. The gravity of a massive galaxy cluster acts similarly to a magnifying glass, amplifying the light from Alaknanda and making it appear significantly brighter. By examining the galaxy across various wavelengths, the team estimated that its stars have an average age of approximately 200 million years, with about half formed in a rapid burst after the universe reached over 1 billion years old.
Future Research Directions
Alaknanda continues to evolve, currently forming new stars at a rate equivalent to around 63 suns per year, which is dozens of times faster than the Milky Way’s current star formation rate. The study’s lead author, Rashi Jain, emphasized the implications of their findings: “The physical processes driving galaxy formation can operate far more efficiently than current models predict.”
Despite this progress, the exact mechanisms behind the rapid formation of spiral arms in such ancient galaxies remain unclear. Some theories propose that these structures arise from slow-moving density patterns within the disks, while others suggest gravitational influences from nearby galaxies or large gas clumps. Alaknanda may even have a small neighboring galaxy that could contribute to its spiral structure, though further evidence is necessary to confirm such claims.
Future observations using the James Webb Space Telescope, paired with radio telescopes, aim to map the motions of stars and gas within Alaknanda, potentially revealing whether its disk has stabilized into a final form or if the spiral arms represent an early developmental phase. The ongoing research into Alaknanda not only illuminates the characteristics of early galaxies but also encourages a reevaluation of our understanding of cosmic evolution.
