What causes the ongoing star formation in Spiral galaxy arms?
Answer
Density waves moving through the galactic disk compressing gas and dust
Spiral galaxies are dynamically active environments precisely because of the structure of their arms. These arms are not static collections of stars but are manifestations of density waves—regions where material rotates slightly slower or faster than the general disk rotation, causing a momentary compression. When interstellar gas and dust encounter these compressed regions, they are squeezed together significantly. This increased density and pressure are the direct triggers for gravitational collapse within the clouds, leading to the birth of new stars, which typically appear bright and blue due to their youth and high temperature.
Related Questions
What specific classification is the Milky Way galaxy given in the Hubble scheme?How are Elliptical galaxies classified based on their apparent flatness?What causes the ongoing star formation in Spiral galaxy arms?What characterizes the stellar population and resulting hue of Elliptical galaxies?What is the most common reason for a galaxy developing an Irregular shape?What function is attributed to the central bar structure in Barred Spirals like the Milky Way?Which three main components make up a typical Spiral galaxy structure?What morphology is predicted for the resulting galaxy after the Milky Way and Andromeda merge?Where is the Solar System located within the Milky Way's disk structure?What key compositional element is notably lacking in Elliptical galaxies compared to Spirals?