Astronomers have identified an ancient galaxy that challenges our understanding of cosmic evolution. The newly observed galaxy, J0107a, remarkably resembles our Milky Way in structure, yet it is vastly more massive and existed in the universe's infancy.
The galaxy, named J0107a, dates back 11.1 billion years, placing it in a time when the universe was just about a fifth of its current age. This makes it one of the earliest-known examples of a barred spiral galaxy, a structure that was thought to be uncommon during such an early epoch.
Using observational data from both NASA's James Webb Space Telescope (JWST) and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, researchers uncovered a galaxy that shares many structural similarities with the Milky Way but vastly outpaces it in mass and star-forming activity.
Mass: J0107a's total mass (stars + gas) is more than 10 times that of the Milky Way.
Star Formation Rate: It forms stars at a rate about 300 times greater than the Milky Way.
Size: Despite being more massive, it is more compact than our galaxy.
Bar Structure: The bar at the galaxy's center stretches about 50,000 light years.
“The galaxy is a monster galaxy with a high star formation rate and plenty of gas, much more than present-day galaxies,” said astronomer Shuo Huang of the National Astronomical Observatory of Japan, lead author of the study published in Nature.
One of the most intriguing aspects of the discovery is that J0107a is not undergoing a galactic merger, which is the typical explanation for high star formation rates in present-day galaxies of similar scale.
“This discovery,” said study co-author Toshiki Saito, an astronomer at Shizuoka University in Japan, “raises the important question: How did such a massive galaxy form in such an early universe?”
In the turbulent billions of years following the Big Bang (13.8 billion years ago), galaxies were often irregular and chaotic in form due to frequent collisions and a high abundance of gas.
“Compared to other monster galaxies in the distant universe (dating to an earlier cosmic epoch) whose shapes are usually disturbed or irregular, it is unexpected that J0107a looks very similar to present-day spiral galaxies,” Huang said.
The discovery could lead to a significant shift in how astronomers understand the development of structured galaxies.
“Theories about the formation of present-day galactic structures may need to be revised,” Huang added.
The bar structure, seen in about two-thirds of spiral galaxies today, plays a vital role in star formation. It channels gas from spiral arms into the galaxy’s core, where it forms molecular clouds, which then collapse under gravity to birth new stars.
“The Webb telescope has been studying the morphology of early massive galaxies intensely recently. However, their dynamics are still poorly understood,” Saito said.
Thanks to the unprecedented resolution and sensitivity of the James Webb Space Telescope, astronomers are now able to peer deeper into the early universe, uncovering well-structured galaxies like J0107a much earlier than previously assumed.
|
Feature |
J0107a |
Milky Way |
|
Age Observed |
11.1 billion years ago |
Present day |
|
Mass |
10x greater than the Milky Way |
— |
|
Star Formation Rate |
300x higher |
— |
|
Bar Length |
50,000 light years |
Comparable, but with more time to form |
|
Merger Activity |
No signs of collision or merger |
— |
The discovery of galaxy J0107a, a barred spiral galaxy from the early universe, challenges long-standing theories about galactic evolution. Despite existing 11.1 billion years ago, this "monster galaxy" shares striking similarities with our Milky Way, yet surpasses it in mass and star formation rate.
Its organized structure defies expectations for galaxies of that cosmic era, suggesting that spiral formations may have emerged much earlier than previously believed.
As telescopes like James Webb and ALMA continue to unlock deep space mysteries, such findings could reshape our understanding of how galaxies formed and evolved in the early universe.