Structure of Galaxies

The classification of spiral galaxies are based on  tightness of spiral arms and 

• how many stars are in galaxy
• brightness of galaxy
• size of nuclear bulge
• velocity of galaxy

Who came up with the classification scheme for galaxies?

• Carl Sagan
• Edwin Hubble
• Neil Armstrong
• Neil Tyson

What type of galaxy is this?

• Spiral
• Elliptical
• Irregular
• Irrational

What type of galaxy is this?

• Spiral
• Elliptical
• Irregular 
• Irrational

What type of galaxy is this?

• Spiral
• Elliptical
• Irregular
• Irrational

What type of galaxy is this?

• Spiral
• Elliptical
• Irregular
• Irrational

What type of galaxy is this?

• Spiral
• Elliptical
• Irregular
• ring

How are galaxies held together.

• gas
• dust
• stars
• gravitational attraction

What type of galaxy is this?

• Spiral
• Elliptical
• Irregular
• Irrational

Our Galaxy is called the

• M38
• Milky Way Galaxy
• Andromeda Galaxy
• Pinwheel Galaxy