2. Elliptical galaxies [1]are spheroid-shaped. We can see only 2 of 3 dimensions of them from earth, so they look like elliptical disks. They have no particular axis of rotation. There is a complicated classification system within it. The galaxy could be ranked from E0 – E7, E0 being perfectly circular and E7 being flattened. ELLIPTICAL
5. Spiral Galaxies [2] are made up of 3 main parts – the nucleus/bulge, disk, and the halo. The bulge, in the center of the galaxy, is spherical and contains older stars. SPIRAL
10. S0 Galaxies [3], also called Lenticular galaxies, are between an E7 and a “true” spiral SA. They are different than elliptical galaxies because they have a bulge AND thin disk, yet NO spiral structure of any kind. S0 GALAXIES
12. Irregular Galaxies [4] have no regular or symmetrical structure. The two types are IrrI and IrrII. Irr type 1 have HII (elemental hydrogen gas and young hot stars) regions, whereas Irr type 2 galaxies have large amounts of dust that block starlight, making it hard to distinguish stars. IRREGULAR