Galaxy mergers and interactions are fundamental drivers of morphological transformation, starbursts, and the growth of supermassive black holes.

Galaxies are not static entities; they are constantly interacting within the cosmic web. Collisions and mergers between galaxies are common events, especially in dense regions like galaxy clusters. These gravitational encounters can dramatically reshape galaxies, stripping away gas, triggering intense bursts of star formation (starbursts) as gas clouds collide and compress, and often leading to the eventual merger of their central supermassive black holes. The 'Antennae Galaxies' and the 'Tadpole Galaxy' are iconic examples of galaxies caught in the act of merging. Major mergers are thought to be a primary pathway for the formation of large elliptical galaxies from spiral progenitors. The chaotic dynamics of a merger disrupt the ordered disks of spirals, scattering stars into a more randomized, elliptical distribution. Such mergers also funnel gas towards the galactic center, fueling the growth of the central supermassive black hole and often igniting an Active Galactic Nucleus. Observations from telescopes like the Hubble Space Telescope and the James Webb Space Telescope provide compelling visual evidence of these transformative processes.