Spiral
A rotating disk system with a central concentration and spiral structure; bars may also cross the center.
Flagship system · Variation Comparator
Variation
Morphology is a disciplined way to describe visible form. It becomes misleading when treated as destiny, age, value or a complete causal history.
sourced NASA’s overview distinguishes spirals, ellipticals, lenticulars and irregulars, while active galaxies are classified by energetic central activity rather than by shape alone.
Sources: GX-SRC-002 · GX-SRC-004
Elliptical
A round-to-oval stellar system that usually shows less obvious large-scale structure in visible light than a spiral disk.
Lenticular
A disk-and-bulge morphology without obvious spiral arms, bridging visual features commonly associated with spirals and ellipticals.
Irregular
A galaxy without a clear spiral or elliptical morphology; interactions, star formation and small size can all contribute to complex appearances.
Active galaxy
A galaxy whose central region emits unusually strong energy associated with matter around a supermassive black hole; activity can occur across different morphologies.