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Why are distant young galaxies often irregular and asymmetrical?

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Whirlpool Galaxy (M51); NGC 5195 — Galaxy The Whirlpool Galaxy (left), also known as M51, an Sc galaxy accompanied by a small irregular companion galaxy, NGC 5195 (right).

Distant, young galaxies appear irregular and asymmetrical because they represent the early building blocks of the universe, rather than the mature, structured systems seen today.1

In the early universe, galaxies did not evolve in isolation; instead, they grew through the frequent collision and merger of smaller entities. Observations from deep surveys, such as those conducted by the Hubble Space Telescope, reveal that the early universe was populated by small, fragmented objects rather than grand spirals or giant elliptical galaxies. These irregular shapes are the result of these ongoing gravitational interactions and the amalgamation of smaller galactic pieces.1

Furthermore, these young galaxies often exhibit high rates of star formation, which contributes to their chaotic appearance. As these smaller building blocks eventually merged over time, they formed the larger, more stable galaxies observed in the modern universe.1