New discoveries Mysterious Activity Detected in Galaxy M83 Read time: 3 minutes How are stars born? This is a fascinating phenomenon that the scientific community has been studying for many years. We know that atoms come together, creating molecular clouds with high-density cores that then turn into a star. To understand how particles attract each other, try to picture a lot of dust floating through space whose mass attracts other particles due to gravity, just as Earth does with us. As these “dust” particles come together, creating a denser gas that is easier to see, it condenses into what we call molecular clouds. Within these molecular clouds, there is a denser area known as a core, and it is there where star formation begins. This process is very common in the inner part of galaxies, but as we move away from the center and go to its edges, we can see that it is much more difficult for this process to occur. Despite this, there are a large number of young stars. This contradiction makes the origin and formation of these stars a great mystery. Recent observations led to first-time identifications of small molecular cloud cores in the outskirts of the galaxy M83. They are rare because there is no molecular cloud around them, something completely out of the ordinary. These data will help us better understand how stars form in the outermost regions of galaxies. Finally, it was discovered that in these regions, far from the galactic center, there is a huge amount of diffuse atomic gas, but it does not turn into molecular clouds. In other words, it does not behave as previously described, in which the “dust” condenses and turns into cores where the stars will be born, raising more questions than answers about the behavior of this star-forming gas. What was observed? 23 molecular cloud cores on the outer border of the galaxy M83. There, two new discoveries were made: a new type of molecular cloud and a large reservoir of diffuse atomic gas. Who observed this? An international scientific team led by Jin Koda, an astronomer at Stony Brook University. The results were presented at the American Astronomical Society (AAS) 243rd meeting in New Orleans (Louisiana, USA). To carry out this study, observations were made with the Atacama Large Millimeter/submillimeter Array (ALMA), the Karl G. Jansky Very Large Array (VLA), and the NRAO Green Bank Telescope (GBT), as well as the Subaru telescope of the National Astronomical Observatory of Japan (NAOJ) and NASA's Galaxy Evolution Explorer (GALEX). ALMA URL