A Universe of Galaxy Shapes

Galaxy classification reveals how structure connects to history:

• Spirals have rotating disks with density-wave arms and active star formation
• Barred spirals channel gas inward through a central bar
• Ellipticals are smooth, old, and often formed from galaxy mergers
• Irregulars are shaped by gravitational interactions with neighbors
• Dwarfs are the most common type but the hardest to spot

Galaxy shape is not permanent: spirals can become ellipticals through mergers as the universe keeps reshaping its galaxies.