Which galaxy type lacks a regular shape and often appears chaotic?

• A. Spiral
• B. Elliptical
• C. Lenticular
• D. Irregular

Answer: (D)

Galaxies vary in how regular their shapes are, and the one that lacks a well-defined, symmetric structure is described as irregular. An irregular galaxy doesn’t show the orderly features of a disk with spiral arms or a smooth ellipsoidal glow; it often looks chaotic, with an uneven distribution of stars, gas, and dust. This irregular appearance can come from gravitational interactions with other galaxies, causing distortions, or from uneven, patchy star formation within the galaxy itself. By contrast, spiral galaxies have a flat disk with bright spiral arms and a central bulge, elliptical galaxies are smooth and rounded, and lenticular galaxies have a disk-like shape but no prominent spiral arms. So the description of lacking a regular shape and appearing chaotic best fits irregular galaxies.