Hubble's Galaxy Classification

Spiral galaxies are best described as

• irregular in shape with random star movement.

• regular in shape with mostly orderly star movement.

• having a huge round shape with mostly very old stars.

• having a galactic bulge with a huge central black hole.

Spiral galaxies also contain massive lanes of gas & dust which leads to

• supermassive black holes.

• quasars.

• large regions of new star formation.

• aliens.

"Barred" spiral galaxies are called that because

• they have very little material at the center.

• they are really elliptical in shape.

• they have a massive bar of material at the center.

• of massive supernovae explosions near the center.

Barred spirals (SB) are further classified as "SBa" & "SBb" etc. based on

• the size of the central supermassive black hole.

• the distances of stars to the supermassive black hole.

• the amount of stars near the galactic bulge.

• stars that make up the bar size & shape.

Astronomers currently classify the Milky Way as a(n)

• "SBa" barred spiral.

• "SBc" barred spiral.

• "SBb" barred spiral.

• "SBd" barred spiral.

Elliptical galaxies can be described as having

• no spiral arms and mostly very old stars.

• a circular or elongated shape.

• some spiral structure with lots of gas & dust.

• an irregular shape with mostly old stars.

Compared to most elliptical galaxies, spiral galaxies are

• very large by comparison.

• very small by comparison.

• about the same size.

• are similar in size and shape to irregular galaxies.

The formation of giant elliptical galaxies may have been created by

• collisions of supermassive black holes.

• supernovae explosions and star mergers.

• collisions and mergers of small irregular galaxies.

• collisions and mergers of spiral galaxies.

Irregular galaxies are defined as having

• very little star formation.

• no real shape and are comparatively very small.

• massive star formation.

• supermasive black holes.

Examples of irregular galaxies include

• the LMC and SMC.

• M31 & IC 1101.

• the Milky Way and Andromeda.

• the LMC & the Milky Way.