Astronomers have discovered a remarkably orderly distant galaxy named REBELS-25 using the Atacama Large Millimetre/submillimetre Array (ALMA) telescope, which shows surprising similarities to the Milky Way despite being much younger.
REBELS-25 exhibits a rotation-dominated structure, unlike expectations that early systems would appear clumpy and chaotic. “According to our understanding of galaxy formation, we expect most early systems to be small and messy-looking,” said Jacqueline Hodge, an astronomer at Leiden University, as per CNN. Thus, this discovery challenges the current understanding of cosmic formation.
Dave Clements, an astrophysicist from Imperial College London, called the galaxy's disc-like structure unexpected for such an early stage in the universe's development. “The universe back then is thought to be a lot more chaotic,” Mr Clements explained. He questioned whether REBELS-25 is an outlier or indicative of flawed galaxy formation theories.
The galaxy is seen as it was when the Universe was only 700 million years old. This relatively short timeline for REBELS-25's formation contradicts the traditional view of galaxies evolving slowly over billions of years. “Seeing a galaxy with such similarities to our own Milky Way... challenges our understanding of how quickly galaxies in the early Universe evolve,” noted Lucie Rowland, the study's lead author and a doctoral student at Leiden University.
Andrew Blain, a professor of astrophysics at the University of Leicester, described the discovery as “a bit unusual,” saying that it is not revolutionary but noteworthy. He explained how ALMA has played a crucial role in finding these galaxies, which would otherwise be too faint to detect. Mr Blain said, “ALMA also reveals details finer than earlier telescopes.”
The research has been accepted for publication in the Monthly Notices of the Royal Astronomical Society, and further observations are planned to confirm the presence of spiral arms and other advanced structures.
