Galaxies Dying: Scientists Uncover Cosmic Culprit

Astronomers have identified a phenomenon called ram-pressure stripping as a primary cause of galaxy death. This process involves superheated intergalactic plasma violently sweeping gas from galaxies as they move through large dark matter halos. This removal of gas, essential for star formation, effectively 'kills' the galaxy by preventing the birth of new stars.

The new research, utilizing extensive optical and radio surveys, demonstrates that ram-pressure stripping is far more common than previously understood. While known to affect galaxies in dense clusters, the study reveals it also impacts galaxies in smaller groups. This suggests that the stripping of gas is a dominant mechanism for galaxy quenching across the local Universe.

Another process, known as strangulation, also leads to galaxies running out of gas. However, ram-pressure stripping is a much faster, more aggressive event, removing a galaxy's fuel in tens of millions of years. This rapid gas depletion dictates the galaxy's lifespan, ultimately turning it into a dormant object.