The galaxies become more chaotic as they grow

Important are the conclusions reached for the international research team, led by the Australian research center ASTRO 3D, in the magazine “Monthly Notices of the Royal Astronomic Society” (MNRAS). According to this age it is the driving force that changes the way stars move within galaxies that become more chaotic. The galaxies begin their lives with their stars spinning into an organized pattern, however in some the movement of stars is more random. So far scientists have not been sure what causes this, possibly the environment or mass of the galaxy itself. The new study finds that the most important factor is none of these two. It shows that the tendency of stars to have random movement is determined primarily by the age of the galaxy. “If you find a young galaxy, it will revolve in whatever environment it is, while if you find an old galaxy, it will have more random orbits, whether it is in a dense environment or in a vacuum,” points out the first writer, professor at the University of Sydney, Scott Krum. Second writer Jesse van de Sad explains that the previous work proposed by the environment or mass as more important factors is not necessarily incorrect. New galaxies are super-productive star production units, while in older galaxies star formation ceases. “We know that age is influenced by the environment. If a galaxy falls into a dense environment it will tend to stop star formation. Thus, galaxies in denser environments are, on average, older in age,” he says and adds: “Our analysis underlines that it is not living in dense environments that reduce their rotation, but the fact that they are older at age”.