The fate of massive gas outflows observed by ALMA depends largely on the velocity of the gas and the gravitational pull of the host galaxy. These outflows occur when intense energy from starburst activity or an active galactic nucleus pushes huge amounts of gas out of the galactic disk.
If the gas travels faster than the galaxy's escape velocity, it will indeed escape into intergalactic space. This process can deplete the galaxy of its star-making material, effectively quenching star formation and slowing down the growth of the galaxy over time.
However, in many observed cases, the gas does not reach escape velocity. This material eventually loses its momentum and falls back toward the galactic plane in a process often referred to as a galactic fountain. Once this gas returns, it can cool and settle, providing a fresh supply of fuel that triggers new rounds of star formation. This cycle plays a critical role in regulating how galaxies evolve and how quickly they consume their available gas reservoirs.
