Galaxies

n. gal·ax·y: An enormous collection of stars,
with some gas and dust added in.

Four Classes of Galaxies

Elliptical Galaxy Elliptical
Vary in size, show no spiral structure at all and range from flattened cigar shapes to spheres.

Spiral Galaxy Spiral
Spiral arms traced out by bright, young stars surrounding a nuclear bulge.

Barred Spiral Galaxy Barred spiral
Similar to Spiral. Instead they feature a bar across the nuclear region, with the spiral arms trailing off the ends of the bar.

Irregular Galaxy Irregular
No definite form; shapeless.

Clusters: Collection of near galaxies

Local group: Collection of nearest galaxies (contains about 30 of them)

Peculiar Galaxies: Any galaxy that seems to have suffered some kind of severe disturbance.

Seyfert Galaxies: Great spiral systems with bright centers. Part of a continuum of "active" galaxies with unusual, often violent, core activity.