Interstellar Medium
This cosmic material fills the vast gaps between star systems, serving as a reservoir of gas and dust that shapes galactic evolution.
This substance constitutes the matter and energy residing in the regions of space between stellar populations. It functions as a dynamic laboratory where gravity, radiation pressure, and supernova shocks interact to cycle matter between various physical states. Understanding its fluid behavior is critical because it dictates how stars are born and how galaxies evolve over billions of years. While it was once viewed as a passive vacuum, recent mapping reveals it to be a turbulent environment, contrasting sharply with the traditional perception of a static, empty void. Also abbreviated as ISM.