A galaxy spiral shaped, Similar to the Milky Wayappeared at a time when such an organization should not exist according to current models. Two Indian astronomers have identified a surprisingly mature system “only” 1.5 billion years after the Big Bang, a discovery that challenges what was thought about galactic evolution.
he James Webb Space Telescope (JWST), capable of detecting the faintest light in the early universe, allowed researchers Rashi Jain and Yogesh Wadekar to observe a galaxy that is strikingly similar to our own.
They baptized her Alaknandasuch as the Himalayan River, one of the twin tributaries of the Ganges River whose name in Hindi also refers to the Milky Way. The study was conducted at the National Center for Radio Astrophysics of the Tata Institute of Fundamental Research (NCRA-TIFR) in Pune, and was published in the journal Astronomy and Astrophysics.
For decades, astronomers have maintained that “highly designed” spiral galaxies, with well-defined, symmetrical arms, require billions of years to form. According to this opinion, The early universe must have been populated by chaotic structuresirregular, still in the assembly process.
Alaknanda It contradicts these ideas. It has two spiral arms that wrap around a huge core, extending about 30,000 light-years. In addition, it forms new stars at a rapid pace: lThe mass is equivalent to 60 suns per year, about twenty times more than the current Milky Way. It is estimated that half of its stars were born within only 200 million years.
“Alaknanda has the structural maturity that we associate with galaxies billions of years older.”Jain explains. “Finding such a well-organized spiral disk at this time tells us that the physical processes driving galaxy formation can operate much more efficiently than current models predict. It forces us to rethink our theoretical framework.”
The galaxy is located in the direction of the Abell 2744 cluster, also called the Pandora cluster. The cluster’s enormous gravity acts as a natural lens, amplifying light coming from distant objects, a phenomenon known as gravitational lensing. Thanks to this effect, the James Webb Space Telescope was able to clearly capture the spiral structure of Alaknanda.
Jain and Wadekar analyzed images taken through 21 different filters, allowing them to accurately estimate the galaxy’s distance, its dust content, the number of its stars, and the speed at which these stars are forming. The data belongs to the Uncover and MegaScience programs of JWST.
This discovery adds to other recent observations that reveal this The early universe was much more mature than previously assumed. Although other disk-shaped galaxies at similar distances have already been identified, Alaknanda stands out as one of the clearest examples of highly designed spiral galaxies at such an early stage.
“Alaknanda reveals that the early universe was able to assemble galaxies much faster than we expected.”Wadadkar said. He added: “Somehow, this galaxy managed to pack ten billion solar masses into stars and organize them into a beautiful spiral disk in just a few hundred million years. This is very fast in cosmological terms, and is forcing astronomers to rethink how galaxies form.”
formation Its spiral arms remain a mystery. One possibility is that the galaxy grew stably by feeding on streams of cold gas, allowing density waves to form the arms. Another possibility is that gravitational interaction with a smaller galaxy led to the formation of the structure.
Future observations using JWST spectrographs or the ALMA radio telescope could measure the disk’s rotational speed and the level of its internal order, thus determining whether its dynamics are “cold” or “hot,” a key to understanding its origin.
But beyond the structural mystery, Alaknanda’s presence redraws the timeline of the universe. It suggests that the conditions necessary to form complex structures – and ultimately worlds like ours – may have appeared much earlier than we imagine.
Written by Alejandra Lopez Plaza